INITIALIZATION Knowledgebase: ki-dev-large Base Query: Schreib mir eine zusammenfassung von Öle und Lacke Model: gpt-4o Use Curl?: ================================================== **Elapsed Time: 0.00 seconds** ================================================== ROUTING Query type: summary ================================================== **Elapsed Time: 1.68 seconds** ================================================== PRIMER Primer: You are Simon, a highly intelligent personal assistant in a system called KIOS. You are a chatbot that can read knowledgebases through the "CONTEXT" that is included in the user's chat message. Your role is to act as an expert at summarization and analysis. In your responses to enterprise users, prioritize clarity, trustworthiness, and appropriate formality. Be honest by admitting when a topic falls outside your scope of knowledge, and suggest alternative avenues for obtaining information when necessary. Make effective use of chat history to avoid redundancy and enhance response relevance, continuously adapting to integrate all necessary details in your interactions. Use as much tokens as possible to provide a detailed response. ================================================== **Elapsed Time: 0.37 seconds** ================================================== FINAL QUERY Final Query: CONTEXT: ########## File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 2 Context: I'm unable to process the image you mentioned. Please provide the text directly so I can help you with the Markdown formatting. Image Analysis: ### Comprehensive Examination of the Attached Visual Content #### 1. Localization and Attribution - **Image Identified**: Single image provided. - **Image Number**: Image 1. #### 4. Text Analysis - **Text Detected and Extracted**: - Upper Portion: "14", "TECHNOLOGY" - Middle Portion: "Artificial Intelligence and Machine Learning" - Lower Portion: "Outputs of AI in different environments" - Text in the diagram: - Center of diagram: "AI and ML" - 6 connected nodes: "Healthcare", "Finance", "Retail", "Education", "Transportation", "Manufacturing" - **Text Content Analysis**: - The headings suggest the image focuses on the impact and application of Artificial Intelligence (AI) and Machine Learning (ML) in various sectors. - "Outputs of AI in different environments" indicates that the diagram illustrates AI's applications or results in different domains. #### 5. Diagram and Chart Analysis - **Diagram Description**: - The diagram is a central node labeled "AI and ML" connected to six outer nodes with directional arrows pointing away from the center. - **Nodes' Labels**: - Different sectors: "Healthcare", "Finance", "Retail", "Education", "Transportation", "Manufacturing". - **Insights**: - This diagram represents how AI and ML are applied or impacting various key industries, suggesting a wide range of use cases and benefits across these sectors. #### 6. Product Analysis - **Products Depicted**: - Not applicable. #### 7. Anomaly Detection - **Possible Anomalies**: - No notable anomalies were detected in the image. All elements appear consistent with the intended message and layout of the illustration. #### 8. Color Analysis - **Color Composition**: - The image uses a color scheme primarily involving shades of blue and white. - The center "AI and ML" node is highlighted in blue, while the outer nodes use blue text, creating a cohesive visual theme. - This color scheme gives a technological, modern feel to the infographic. #### 9. Perspective and Composition - **Perspective Description**: - The image is a 2D diagram seen from a direct, head-on perspective. - **Composition Analysis**: - The composition centers around a main node labeled "AI and ML" with equal spacing and connections to six outer nodes representing different sectors. - The layout is symmetrical and ensures that each industry related to AI and ML is easily readable and visually connected to the central theme. ### Summary This image (Image 1) is an infographic focusing on the applications and impacts of Artificial Intelligence (AI) and Machine Learning (ML) across various industries. The arranged sectors include Healthcare, Finance, Retail, Education, Transportation, and Manufacturing. The visual employs a consistent blue and white color scheme to convey a modern, technological theme, with text and arrows providing clarity on the relationships. The image’s structure is balanced and aims to inform viewers about the diverse areas where AI and ML are influential. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 3 Context: # Contents 1. **Preface** 1.1 About the author ................................................................................................................ 4 2. **Part 1: Introduction** 2.1 Introduction ..................................................................................................................... 5 2.2 Services and protocols .................................................................................................... 11 2.3 The reference models ...................................................................................................... 21 2.4 Organisation of the book ................................................................................................ 26 3. **Part 2: The Application Layer** 3.1 The application Layer ..................................................................................................... 27 3.2 Principles ....................................................................................................................... 27 3.3 The transport services ..................................................................................................... 30 3.4 Application-level protocols ............................................................................................. 31 3.5 Writing simple networked applications ......................................................................... 55 3.6 Summary ........................................................................................................................ 61 3.7 Exercises ........................................................................................................................ 61 4. **Part 4: The Transport Layer** 4.1 Principles of a reliable transport protocol ...................................................................... 67 4.2 The User Datagram Protocol .......................................................................................... 87 4.3 The Transmission Control Protocol ............................................................................... 94 4.4 Exercises ........................................................................................................................ 114 4.5 Practice ........................................................................................................................... 119 5. **Part 5: The Network Layer** 5.1 The network layer .......................................................................................................... 129 6. **Part 6: The datalink layer and the Local Area Networks** 6.1 The datalink layer and the Local Area Networks ......................................................... 215 7. **Part 7: Appendices** 7.1 Glossary ........................................................................................................................... 253 7.2 Bibliography ................................................................................................................... 257 7.3 Indices and tables ........................................................................................................... 257 **Bibliography** **Index** #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 4 Context: I'm unable to view or analyze images. If you provide the text you want formatted, I can assist with that. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 5 Context: # Computer Networking ## Principles, Protocols and Practice --- Contents 1. Introduction 2. Networking Concepts 3. Protocols 4. Implementation 5. Future Perspectives --- Image Analysis: ### Comprehensive Examination of the Attached Visual Content #### Image Localization and Attribution - **Image 1** is the only image on the page, located centrally. #### Object Detection and Classification - **Image 1** contains the following objects: - Network devices such as routers, servers, and switches. - A computer monitor, a document, and some networking cables. - Text elements. #### Scene and Activity Analysis - **Image 1** depicts an illustrative and schematic representation of a computer network. - **Main Actors and Actions:** - Various network devices connected to each other, suggesting data flow and communication between them. #### Text Analysis - **Image 1** contains the following text: - "Computer Networking" - "Principles Protocols and Practice" - **Significance:** - The text indicates the topic of the image, which is centered around computer networking and its various principles, protocols, and practices. #### Color Analysis - **Image 1** uses a combination of blue, black, and red colors: - **Dominant Colors:** - Blue: used for the text "Computer Networking... Practice" and some network devices, symbolizing trust and technology. - Black: used for the circuit/flow diagram. - Red: used for certain network devices, drawing attention to important components. #### Perspective and Composition - **Image 1** is created from a front orthogonal view which is typical for schematic diagrams, allowing clear visibility of all components. - **Composition:** - The elements are arranged in a structured manner with network devices interlinked, depicting an orderly network structure. - The text is placed on the left side and the illustrative diagram on the right ensures readability and clear association with the concepts mentioned in the text. #### Contextual Significance - **Image 1** is evidently the cover or introductory page of a document titled "Computer Networking: Principles, Protocols, and Practice." - **Contribution to Overall Message:** - Sets the tone for the document by providing a visual summary of the subject matter. - Immediately informs the viewer that the document will cover principles, protocols, and practice related to computer networking. This analysis concludes that **Image 1** acts as an engaging and informative introduction to a document on computer networking, effectively using visual elements to represent key concepts in the field. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 6 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Contents 1. **Introduction** - Overview of computer networking - Importance of networking in modern society 2. **Types of Networks** - Local Area Network (LAN) - Wide Area Network (WAN) - Metropolitan Area Network (MAN) - Personal Area Network (PAN) 3. **Network Protocols** - Definition of protocols - Types of protocols - Transmission Control Protocol (TCP) - Internet Protocol (IP) - User Datagram Protocol (UDP) 4. **Networking Models** - OSI Model - TCP/IP Model 5. **Network Hardware** - Routers - Switches - Hubs - Modems 6. **Wireless Networking** - Wi-Fi Standards - Security Issues in Wireless Networks 7. **Network Security** - Types of threats - Security protocols 8. **Future of Networking** - Emerging trends in networking ## References - Additional reading materials and resources ## Acknowledgements - Contributors and collaborators involved in the project #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 7 Context: # CHAPTER 1 ## Preface This textbook came from a frustration of its main author. Many authors chose to write a textbook because there are no textbooks in their field or because they are not satisfied with the existing textbooks. This frustration has produced several excellent textbooks in the networking community. At a time when networking textbooks were mainly theoretical, Douglas Comer chose to write a textbook entirely focused on the TCP/IP protocol suite (Comer 1988), a difficult choice at that time. He later extended his textbook by describing a complete TCP/IP implementation, adding practical considerations to the theoretical descriptions in (Comer 1988). Richard Stevens approached the Internet like an explorer and explained the operation of protocols by looking at all the packets that were exchanged on the wire [Stevens 1994]. Jim Kurose and Keith Ross reinvented the networking textbooks by starting from the applications that the students use and later explained the Internet protocols by removing one layer after the other [KuroseRoss 2009]. The frustrations that motivated this book are different. When I started to teach networking in the late 1990s, students were already Internet users, but their usage was limited. Students were still using reference textbooks and spent time in the library. Today’s students are completely different. They are avid and experimented web users who find lots of information on the web. This is a positive attitude since they are probably more curious than their predecessors. Thanks to the information that is available on the Internet, they can check or obtain additional information about the topics explained by their teachers. This abundant information creates several challenges for a teacher. Until the end of the nineteenth century, a teacher was by definition more knowledgeable than his students and it was very difficult for the students to verify the lessons given by their teachers. Today, given the amount of information available at the fingertips of each student through the Internet, verifying a lesson requires more information about a given topic is sometimes only a few clicks away. Websites such as Wikipedia provide lots of information on various topics and students often consult them. Unfortunately, the organization of the information on these websites is not well suited to allow students to learn from them. Furthermore, there are huge differences in the quality and depth of the information that is available for different topics. The second reason is that the computer networking community is a strong participant in the open-source movement. Today, there are high-quality and widely used open-source implementations for most networking protocols. This includes the TCP/IP implementations that are part of Unix, freedos or the uIP stack running on 8bits controllers, but also for routers such as bind, unbound, apache or sendmail and implementations of routing protocols such as xorp or quagga. Furthermore, the documents that define almost all of the Internet protocols have been developed within the Internet Engineering Task Force (IETF) using an open process. The IETF publishes its protocol specifications in the publicly available RFC and new proposals are described in the Internet drafts. This open textbook aims to fill the gap between the open-source implementations and the open-source network specifications by providing a detailed but pedagogical description of the key ideas behind the operation of the Internet. The book is released under a creative commons license. Such an open-source license is motivated by two reasons. The first is that I hope that other teachers will reuse, adapt and improve it. Time will tell if it is possible to build a community of contributors to improve and develop the book further. As a starting point, the first release contains all the material for a one-semester first year undergraduate networking course. As of this writing, most of the text has been written by Olivier Bonaventure, Laurent Vanbever, Virginie Van den #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 8 Context: Schrieck, Damien Sauzec, and Mickael Hoerdt have contributed to exercises. Pierre Reinbold designed the icons used to represent switches and Nipaloo Long has redrawn many figures in the SVG format. Stéphane Bortzmeyer sent many suggestions and corrections to the text. Additional information about the textbook is available at [http://info.ucl.ac.be/CNP3](http://info.ucl.ac.be/CNP3). **Note:** *Computer Networking: Principles, Protocols and Practice,* (c) 2011, Olivier Bonaventure, Université catholique de Louvain (Belgium) and the collaborators listed above, used under a Creative Commons Attribution (CC BY) license made possible by funding from The Saylor Foundation’s Open Textbook Challenge in order to be incorporated into Saylor.org’s collection of open courses available at [http://www.saylor.org](http://www.saylor.org). Full license terms may be viewed at: [http://creativecommons.org/licenses/by/3.0/](http://creativecommons.org/licenses/by/3.0/) # 1.1 About the author Olivier Bonaventure is currently professor at Université catholique de Louvain (Belgium) where he leads the IP Networking Lab and is vice-president of the ICTEAM institute. His research has been focused on Internet protocols for more than twenty years. Together with his Ph.D. students, he has developed traffic engineering techniques, performed various types of Internet measurements, improved the performance of routing protocols such as BGP and IS-IS and participated to the development of new Internet protocols including shim6, LISP and Multipath TCP. He frequently contributes to standardisation within the IETF. He was on the editorial board of IEEE/ACM Transactions on Networking and is Education Director of ACM SIGCOMM. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 9 Context: # Chapter 2 ## Part 1: Introduction ### 2.1 Introduction When the first computers were built during the Second World War, they were expensive and isolated. However, after about twenty years, as their prices gradually decreased, the first experiments began to connect computers together. In the early 1960s, researchers including Paul Baran, Donald Davies, or Joseph Licklider independently published the first papers describing the idea of building computer networks [Baran1964][Licklider1963]. Given the cost of computers, sharing them over a long distance was an interesting idea. In the US, the ARPANET started in 1969 and continued until the mid-1980s [LCCDP]. In France, Louis Pouzin developed the Cyclades network [Pouzin1975]. Many other research networks were built during the 1970s [Morse]. At the same time, the telecommunication and computer industries became interested in computer networks. The telecommunication industry bet on the X.25. The computer industry took a completely different approach by designing Local Area Networks (LAN). Many LAN technologies such as Ethernet or Token Ring were designed at that time. During the 1980s, the need to interconnect more and more computers led most computer vendors to develop their own suite of networking protocols. Xerox developed [XNS], DEC chose DCN [Mallalieu1991], IBM developed SNA [McFadyen1976]. Microsoft introduced NetBIOS [Winston2003], Apple set up AppleTalk [SAA1990]. In the research community, ARPANET was decommissioned and replaced by TCP/IP [LCCDP] and the reference implementation was developed inside BSD Unix [McKusick1999]. Universities who were already running Unix could adopt TCP/IP easily and vendors of Unix workstations such as Sun or Silicon Graphics included TCP/IP in their variant of Unix. In parallel, the ISO, with support from the governments, worked on developing an Open Systems Interconnection suite of networking protocols. In the end, TCP/IP became the de facto standard that is not only used within the research community. During the 1990s and early 2000s, the growth of the usage of TCP/IP continued, and today proprietary protocols are seldom used. As shown by the figure below, this provides the estimation of the number of hosts attached to the Internet, the Internet has sustained large growth throughout the last 20+ years. Recent estimations of the number of hosts attached to the Internet show a continuing growth since 20+ years. However, although the number of hosts attached to the Internet is high, it should be compared to the number of mobile phones that are in use today. More and more of these mobile phones will be connected to the Internet. Furthermore, thanks to the availability of TCP/IP implementations requiring limited resources such as [Dunkels200320], we can expect to see a growth of TCP/IP embedded embedded devices. Before looking at the services provided by computer networks, it is useful to agree on some terminology that is widely used in networking literature. First of all, computer networks are often classified in function of the geographical area that they cover: - **LAN**: A local area network typically interconnects hosts that are up to a few tens of kilometers apart. - **MAN**: A metropolitan area network typically interconnects devices that are up to a few hundred kilometers apart. *Open in 1960s was in contrast with the proprietary protocols whose specifications were not always publicly available. The US government even mandated the usage of the OSI protocols (see RFC 1169), but this was not sufficient to encourage end users to switch to the OSI protocol suite that was considered by many as no complex compared to other protocol suites.* #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 10 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Estimation of Hosts on the Internet ![Estimation of the number of hosts on the Internet](path/to/image1) _Figure 2.1: Estimation of the number of hosts on the Internet._ ![Estimation of the number of mobile phones](path/to/image2) _Figure 2.2: Estimation of the number of mobile phones._ - **WAN**: A wide area network interconnects hosts that can be located anywhere on Earth. Another classification of computer networks is based on their physical topology. In the following figures, physical links are represented as lines while boxes show computers or other types of networking equipment. Computer networks are used to allow several hosts to exchange information between themselves. To allow any host to send messages to any other host in the network, the easiest solution is to organize them as a full-mesh, with a direct and dedicated link between each pair of hosts. Such a physical topology is sometimes used, especially when high performance and high redundancy are required for a small number of hosts. However, it has two major drawbacks: 1. For a network containing *n* hosts, each host must have *n - 1* physical interfaces. In practice, the number of physical interfaces on a node will limit the size of a full-mesh network that can be built. 2. For a network containing *n* hosts, *n(n-1)/2* links are required. This is possible when there are a few nodes in the same room, but rarely when they are located several kilometers apart. The second possible physical organization, which is also used inside computers to connect different extension cards, is the bus. In a bus network, all hosts are attached to a shared medium, usually a cable through a single interface. When one host sends an electrical signal on the bus, the signal is received by all hosts attached to the bus. A drawback of bus-based networks is that if the bus is physically cut, then the network is split into two isolated networks. For this reason, bus-based networks are sometimes considered to be difficult to operate and maintain, especially when the cable is long and there are many places where it can break. Such a bus-based topology was used in early Ethernet networks. A third organization of a computer network is a star topology. In such topologies, hosts have a single physical interface and there is one physical link between each host and the center of the star. The node at the center of the star is the hub. Image Analysis: ### Analysis of the Attached Visual Content --- #### 1. Localization and Attribution - **Figure 2.1**: Located at the top of the page. - **Figure 2.2**: Located below Figure 2.1. The images are presented in sequence from top to bottom. --- #### 2. Object Detection and Classification - **Image 1 (Figure 2.1)**: Graph showing "Internet Domain Survey Host Count". - **Objects Detected**: - Graph plot with data points. - Axis labels. - Data legend. - **Image 2 (Figure 2.2)**: Graph showing "Estimation of the number of mobile phones". - **Objects Detected**: - Graph plot with data points. - Axis labels. - Data legend. --- #### 3. Scene and Activity Analysis - **Image 1 (Figure 2.1)**: - **Scene Description**: Line graph depicting the survey count of internet domain hosts over time. - **Main Activity**: Tracking the growth of internet hosts. - **Image 2 (Figure 2.2)**: - **Scene Description**: Line graph showing the estimated number of mobile phones globally. - **Main Activity**: Demonstrating the increase in mobile phone usage. --- #### 4. Text Analysis - **Image 1 (Figure 2.1)**: - **Text Extracted**: "Internet Domain Survey Host Count", year labels, numerical values on the y-axis. - **Significance**: Provides a visual depiction of the growth trend in the number of internet hosts over several years. - **Image 2 (Figure 2.2)**: - **Text Extracted**: "Estimation of the number of mobile phones", "Millions GSM worldwide", year labels, numerical values on the y-axis. - **Significance**: Shows the trend of increasing mobile phone adoption over time. --- #### 5. Diagram and Chart Analysis - **Image 1 (Figure 2.1)**: - **Axes**: - X-axis: Years ranging from 1995 to 2005. - Y-axis: Number of hosts ranging from 0 to approximately 600,000,000. - **Key Insights**: The graph indicates a sharp upward trend in the number of internet hosts, particularly after 1997. - **Image 2 (Figure 2.2)**: - **Axes**: - X-axis: Years ranging from 1994 to 2007. - Y-axis: Millions of mobile phones, ranging from 0 to 3,000. - **Key Insights**: There is a steep increase in the number of mobile phones starting from the early 2000s. --- #### 9. Perspective and Composition - **Image 1 (Figure 2.1)**: - **Perspective**: Frontal view of a line graph. - **Composition**: Focus on the trajectory of the number of internet hosts over time. - **Image 2 (Figure 2.2)**: - **Perspective**: Frontal view of a line graph. - **Composition**: Emphasis on the growth pattern of mobile phone numbers globally. --- #### 13. Graph Numbers - **Image 1 (Figure 2.1)**: Data not explicitly provided, but the trend shows an increase from near 0 to over 500,000,000. - **Image 2 (Figure 2.2)**: Exact data points are not given, but the visual shows an increase from just under 0 to 3,000 million GSM mobile phones. --- #### Trend and Interpretation - **Internet Hosts (Figure 2.1)**: The number of internet domain hosts escalated exponentially from roughly 1997 to 2005, indicating rapid internet adoption. - **Mobile Phones (Figure 2.2)**: The rise in mobile phone adoption is significant, particularly from around 2000 onwards, reflecting global technological and communication advancements. --- #### Contextual Significance - **Image Contribution**: Both graphs highlight critical growth areas in internet and mobile technology, essential for understanding the broader context of computer networking principles. - **Document Message**: The visuals support the text's discussion on the expanding scope of networks and communication technologies. --- This comprehensive analysis covers the key aspects requested, providing detailed insights into the content and context of each visual element. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 11 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## 2.1. Introduction ### Figure 2.3: A Full Mesh Network ``` [Node 1]---[Node 2] | | [Node 3]---[Node 4] ``` ### Figure 2.4: A Network Organised as a Bus ``` [Node 1]---[Node 2]---[Node 3]---[Node 4] ``` The star can be either a piece of equipment that amplifies an electrical signal, or an active device, such as a piece of equipment that understands the format of the messages exchanged through the network. Of course, the failure of the central node implies the failure of the network. However, if one physical link fails (e.g., because the cable has been cut), then only one node is disconnected from the network. In practice, star-shaped networks are easier to operate and maintain than bus-shaped networks. Many network administrators also appreciate the fact that they can control the network from a central point. Administered from a web interface, or through a console-like connection, the center of the star is a useful point of control (enabling or disabling devices) and an excellent observation point (usage statistics). ### Figure 2.5: A Network Organised as a Star ``` [Node 1] / \ [Node 2] [Node 3] \ / [Node 4] ``` A fourth physical organisation of a network is the Ring topology. Like the bus organisation, each host has a single physical interface connecting it to the ring. Any signal sent by a host on the ring will be received by all hosts attached to the ring. From a redundancy point of view, a single ring is not the best solution, as the signal only travels in one direction on the ring; thus if one of the links composing the ring is cut, the entire network fails. In practice, such rings have been used in local area networks, but are now often replaced by star-shaped networks. In metropolitan networks, rings are often used to interconnect multiple locations. In this case, two parallel links, composed of different cables, are often used for redundancy. With such a dual ring, when one ring fails all the traffic can be quickly switched to the other ring. A fifth physical organisation of a network is the tree. Such networks are typically used when a large number of customers must be connected in a very cost-effective manner. Cable TV networks are often organised as trees. In practice, most real networks combine part of these topologies. For example, a campus network can be organised as follows: ``` (Tree Structure) [Root] / \ [Branch 1] [Branch 2] / \ / \ [Leaf1] [Leaf2] [Leaf3] [Leaf4] ``` Image Analysis: ### 1. **Localization and Attribution:** - **Image 1:** Located in the top part of the page. - **Image 2:** Located below Image 1, directly in the middle of the page. - **Image 3:** Located at the bottom part of the page. ### 2. **Object Detection and Classification:** - **Image 1:** - **Objects:** Network nodes (illustrated as rectangles linked by lines). - **Key Features:** Six nodes connected in such a way that each node is directly linked to every other node. - **Image 2:** - **Objects:** Network nodes (illustrated as rectangles linked in a linear fashion). - **Key Features:** Five nodes connected sequentially in a line (bus topology). - **Image 3:** - **Objects:** Network nodes (illustrated as rectangles connected to a central node). - **Key Features:** Five nodes connected to a single central node (star topology). ### 3. **Scene and Activity Analysis:** - **Image 1:** Represents a full mesh network where all nodes are interconnected. This ensures high redundancy and reliability since every node has a direct connection to every other node. - **Image 2:** Illustrates a bus network topology with nodes connected sequentially to a single communication line. This type of network is simpler but can be prone to failure if the main line gets disrupted. - **Image 3:** Depicts a star network topology. All nodes are connected to a central node, making it easy to manage but creating a single point of failure at the central node. ### 4. **Text Analysis:** - **Image 1:** Caption reads "Figure 2.3: A Full mesh network." - **Image 2:** Caption reads "Figure 2.4: A network organized as a Bus." - **Image 3:** Caption reads "Figure 2.5: A network organized as a Star." ### 5. **Diagram and Chart Analysis:** - **Diagram (Image 1):** Full mesh network diagram showing each node directly connected to every other node. - **Diagram (Image 2):** Bus network diagram showing nodes connected in a sequential manner. - **Diagram (Image 3):** Star network diagram with a central node to which all other nodes are connected. ### 8. **Color Analysis:** - **Image 1:** Dominant colors include blue for nodes and black for connecting lines. - **Image 2:** Dominant colors include blue for nodes and black for the central line. - **Image 3:** Dominant colors include blue for nodes and black for connecting lines. ### 9. **Perspective and Composition:** - **All Images:** The perspective is a straightforward, 2-dimensional schematic view that clearly shows the layout of the nodes and how they are connected. ### 10. **Contextual Significance:** - The images contribute to illustrating different network topologies discussed in the text. Each image visually represents a type of network structure, making it easier for the reader to understand the concepts. ### 13. **Graph Numbers:** - **Image 1:** - **Nodes:** 6 Nodes - **Connections:** 15 Connections (Using the formula for connections in a full mesh network: n(n-1)/2 where n=6) - **Image 2:** - **Nodes:** 5 Nodes - **Connections:** 4 Connections (Sequential connections between 5 nodes) - **Image 3:** - **Nodes:** 5 Nodes (including the central node) - **Connections:** 4 Connections (Each peripheral node connected to the central node) #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 12 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Chapter 2: Part 1: Introduction ### Figures #### Figure 2.6: A network organised as a Ring ![Figure 2.6](link_to_image) #### Figure 2.7: A network organised as a Tree ![Figure 2.7](link_to_image) Image Analysis: ### Comprehensive Examination of Attached Visual Content #### 1. **Localization and Attribution:** - **Image 1:** Positioned at the top half of the page. - **Image 1 Number:** Image 1. - **Image 2:** Positioned at the bottom half of the page. - **Image 2 Number:** Image 2. #### 2. **Object Detection and Classification:** - **Image 1:** - **Objects:** Five network devices. - **Classification:** Network topology devices (presumably switches or routers) arranged in a circle. - **Key Features:** Circular connection, indicating a ring network. - **Image 2:** - **Objects:** Seven network devices. - **Classification:** Network topology devices arranged in a hierarchical manner. - **Key Features:** Hierarchical structure, indicating a tree network. #### 3. **Scene and Activity Analysis:** - **Image 1:** - **Scene:** A visual representation of a ring network topology. - **Activities:** In a ring network, each device is connected to two other devices, forming a circular data path. - **Image 2:** - **Scene:** A visual representation of a tree network topology. - **Activities:** In a tree network, devices are connected in a hierarchical, parent-child structure. #### 4. **Text Analysis:** - **Image 1:** - **Extracted Text:** "Figure 2.6: A network organised as a Ring." - **Significance:** This text labels and describes the network topology depicted in the image. - **Image 2:** - **Extracted Text:** "Figure 2.7: A network organised as a Tree." - **Significance:** This text labels and describes the network topology depicted in the image. #### 5. **Diagram and Chart Analysis:** - **Image 1:** - **Description:** Diagram showing a ring network topology with devices connected in a circular manner. - **Insight:** Ensures redundant paths but can be costly if the number of devices increases. - **Image 2:** - **Description:** Diagram showing a tree network topology with a hierarchical structure. - **Insight:** Efficient for hierarchical data processes and easy to expand. #### 10. **Contextual Significance:** - **Overall Context:** These images are from a textbook titled "Computer Networking: Principles, Protocols and Practice, Release 0.25." - **Contribution to Message:** The images illustrate different types of network topologies, providing a visual aid to understand the concepts discussed in the chapter. #### 13. **Graph Numbers:** - Not applicable as there are no graphs with data points in the images. ### Summary: - **Image 1** illustrates a ring network topology, where each device is connected in a circle, labeled as Figure 2.6. - **Image 2** illustrates a tree network topology, showing a hierarchical structure of devices, labeled as Figure 2.7. - The text under each diagram provides a brief explanation of the depicted network topology. - These visual aids are integral in helping readers understand distinct network organization structures within the broader context of a computer networking principles book. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 13 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 as a ring between the key buildings, while smaller buildings are attached as a tree or a star to important buildings. Or an ISP network may have a full mesh of devices in the core of its network, and trees to connect remote users. Throughout this book, our objective will be to understand the protocols and mechanisms that are necessary for a network such as the one shown below. ![A simple internetwork](image-placeholder) *Figure 2.8: A simple internetwork* The figure above illustrates an internetwork, i.e., a network that interconnects other networks. Each network is illustrated as an ellipse containing a few devices. We will explain throughout the book the different types of devices and their respective roles enabling all hosts to exchange information. As well as this, we will discuss how networks are interconnected, and the rules that guide these interconnections. We will also analyse how the bus, ring and mesh topologies are used to build real networks. The last point of terminology we need to discuss is the transmission modes. When exchanging information through a network, we often distinguish between three transmission modes. In TV and radio transmission, **broadcast** is often used to indicate a technology that sends a video or radio signal to all receivers in a given geographical area. Broadcast is sometimes used in computer networks, but only in local area networks where the number of recipients is limited. 1. The first and most widespread transmission mode is called **unicast**. In the unicast transmission mode, information is sent by one sender to one receiver. Most of today’s Internet applications rely on the unicast transmission mode. The example below shows a network with two types of devices: hosts (drawn as computers) and intermediate nodes (drawn as cubes). Hosts exchange information via the intermediate nodes. In the example below, when host S uses unicast to send information, it sends it via three intermediate nodes. Each of these nodes receives the information from its upstream node or host, then processes and forwards it to its downstream node or host. This is called **store and forward** and we will see later that this concept is key in computer networks. 2. A second transmission mode is **multicast transmission**. This mode is used when the same information must be sent to a set of recipients. It was first used in LANs but later became supported in wide area networks. When a sender requests to send information to N receivers, the sender sends a single copy of the information and the network nodes duplicate this information whenever necessary, so that it can reach all recipients belonging to the destination group. To understand the importance of multicast transmission, consider source S that sends the same information to destinations A, C, and E. With unicast, the same information passes three times on intermediate nodes 1 and 2 twice on node 4. This is a waste of resources on the intermediate nodes and on the links between them. With multicast transmission, host S sends the information to node I that forwards it downstream to node 2. This node creates a copy of the received information and sends one copy directly to host E and the other downstream to node 4. Upon reception of the information, node 4 produces a copy and forwards one to node A and another to node C. ## 2.1. Introduction 9 Image Analysis: ### Image Analysis #### 1. Localization and Attribution: - **Image 1**: Located at the center of the page. - **Figure Reference**: Figure 2.8: A simple internetwork. #### 2. Object Detection and Classification: - **Objects Identified**: - Various types of network devices such as hosts (represented as computers), routers (represented as circles with arrows), and network links (lines connecting devices). - Text labels identifying different components, such as "ISP1," "ISP2," "alpha.com," "beta.be," and "societe.fr." #### 3. Scene and Activity Analysis: - **Scene Description**: The image depicts a simple internetwork, where multiple networks are interconnected using various devices and networks. - **Activities**: The main activities depicted are data transmission and communication between different network segments. Hosts communicate via routers and ISPs. #### 4. Text Analysis: - **Detected Text**: - Labels within the network diagram: "alpha.com," "beta.be," "societe.fr," "ISP1," "ISP2," "PSTN," "ADSL." - Title: Figure 2.8: A simple internetwork. - **Analysis**: The labels indicate different network segments and service providers. The URLs might represent different internet domains managed by those networks. ISP labels denote Internet Service Providers, and PSTN (Public Switched Telephone Network) indicates traditional telephony. #### 5. Diagram and Chart Analysis: - **Analysis**: - The diagram shows different network connections between various ISPs and hosts. - Data flow is illustrated using arrows. - It visually explains how different parts of a network can be connected and interact with each other. #### 6. Product Analysis: - **Description**: The diagram primarily features typical network elements like routers, hosts, and different types of network links (wired and wireless connections). #### 8. Color Analysis: - **Dominant Colors**: Blue, red, green, and black are used to represent different network segments and devices. - **Impact**: The use of colors helps differentiate between various network components and highlights the different areas of the internetwork. #### 9. Perspective and Composition: - **Perspective**: The diagram is presented in a straightforward, top-down view, typical of network diagrams. - **Composition**: Elements are arranged in a clear manner to show the interconnections between different network segments. #### 10. Contextual Significance: - **Contribution to Document**: The image provides a visual aid to understand the concept of an internetwork as described in the text. It helps readers visualize how different network components connect and interact. - **Overall Theme**: The image supports the theme of the document, which is a detailed exploration of computer networking principles, protocols, and practice. #### 13. Graph Numbers: - **Example Interpretation**: The network diagram can be used to discuss the flow of information between nodes, types of networks, and networking topologies. #### Additional Aspect: - **Ablaufprozesse (Process Flows)**: - Process depicted shows data flow from one computer through various routers and ISPs to reach its destination. - **Prozessbeschreibungen (Process Descriptions)**: - The processes involve sending, receiving, and relaying data packets within an interconnected network. - **Typen Bezeichnung (Type Designations)**: - ISP1, ISP2, host systems, routers, and domain labels (alpha.com, beta.be, societe.fr). - **Trend and Interpretation**: - The trend indicates the modern network’s reliance on different ISPs to manage interconnected systems. - It reflects the complexity and hierarchical structure of internet-based communications. ### Text Analysis (Below Diagram): - **Content**: The text explains the concept of internetworks, transmission modes (broadcast, multicast, unicast), and details how information is transmitted between interconnected networks. - **Significance**: Helps in understanding the theoretical background behind the illustrated network diagram, giving readers both visual and verbal explanations. This detailed analysis covers various requested aspects, providing an in-depth understanding of the visual and contextual elements present in the image. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 14 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Chapter 2: Part 1: Introduction ### Figures **Figure 2.9: Unicast transmission** ![Unicast transmission](path/to/unicast-transmission-image) **Figure 2.10: Multicast transmission** ![Multicast transmission](path/to/multicast-transmission-image) Image Analysis: ### Analysis of the Attached Visual Content #### 1. Localization and Attribution - **Image 1**: Figure 2.9 (Unicast transmission) is located near the top half of the page. - **Image 2**: Figure 2.10 (Multicast transmission) is located below Image 1 in the bottom half of the page. #### 2. Object Detection and Classification - **Image 1**: - Objects: Computers, network switches. - Key Features: - Arrows indicating data transmission. - Labeled computers (A, B, C, D, E). - **Image 2**: - Objects: Computers, network switches. - Key Features: - Arrows indicating data transmission. - Labeled computers (A, B, C, D, E). #### 3. Scene and Activity Analysis - **Image 1**: - Scene Description: A network diagram illustrating unicast transmission. - Main Actors and Actions: Computer labeled 'S' sending data to computer 'A' via network switches. - **Image 2**: - Scene Description: A network diagram illustrating multicast transmission. - Main Actors and Actions: Computer labeled 'S' sending data to multiple computers (A, B, C) simultaneously via network switches. #### 4. Text Analysis - **Image 1**: - Detected Text: "Figure 2.9: Unicast transmission". - Significance: Indicates the type of network communication being illustrated. - **Image 2**: - Detected Text: "Figure 2.10: Multicast transmission". - Significance: Indicates the type of network communication being illustrated. #### 12. Graph and Trend Analysis - **Image 1 & Image 2**: - Both images are diagrams depicting different transmission methods (unicast vs. multicast) in a network setting. - Unicast involves direct one-to-one data transfer, while multicast involves one-to-many data transfer. ### Insights: - **Unicast (Image 1)**: Efficient for one-to-one communication but could cause redundancy if the same data is sent to multiple recipients separately. - **Multicast (Image 2)**: Efficient for one-to-many communications as it sends data once to multiple recipients simultaneously, reducing network load. #### 13. Graph Numbers - No numerical data points, as both images are conceptual diagrams rather than traditional graphs. ### Summary Both figures effectively illustrate different networking transmission methods, providing clear visual differentiation between unicast and multicast data transmission. These diagrams facilitate understanding the principles of network communication within this context. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 15 Context: C. Thanks to multicast, the same information can reach a large number of receivers while being sent only once on each link. The last transmission mode is the **anycast** transmission mode. It was initially defined in [RFC 1542](https://tools.ietf.org/html/rfc1542). In this transmission mode, a set of receivers is identified. When a source sends information towards this set of receivers, the network ensures that the information is delivered to one receiver that belongs to this set. Usually, the receiver closest to the source is the one that receives the information sent by this particular source. The anycast transmission mode is useful to ensure redundancy, as when one of the receivers fails, the network will ensure that information will be delivered to another receiver belonging to the same group. However, in practice supporting the anycast transmission mode can be difficult. ![Figure 2.11: Anycast transmission](image-url) In the example above, the three hosts marked with * are part of the same anycast group. When host S sends information to this anycast group, the network ensures that it will reach one of the members of the anycast group. The dashed lines show a possible delivery via nodes 2, 1, and 4. A subsequent anycast transmission from host S to the same anycast group could reach the host attached to intermediate node 3 as shown by the plain line. An anycast transmission reaches a member of the anycast group that is chosen by the network in function of the current network conditions. ## 2.2 Services and Protocols An important aspect to understand before studying computer networks is the difference between a **service** and a **protocol**. In order to understand the difference between the two, it is useful to start with real-world examples. The traditional Post provides a service where a postman delivers letters to recipients. The Post defines precisely which types of letters (size, weight, etc.) can be delivered by using the Standard Mail service. Furthermore, the format of the envelope is specified (position of the sender and recipient addresses, position of the stamp). Someone who wants to send a letter must either place the letter at a Post Office or inside one of the dedicated mailboxes. The letter will then be collected and delivered to its final recipient. Note that for the regular service the Post usually does not guarantee the delivery of each particular letter; some letters may be lost, and some letters are delivered to the wrong mailbox. If a letter is important, then the sender can use the registered service to ensure that the letter will be delivered to its recipient. Some Post services also provide an acknowledged service or an express mail service that is faster than the regular service. In computer networks, the notion of service is more formally defined in [X200]. It can be better understood by considering a computer network, whatever its size or complexity, as a black box that provides a service to **users**, as shown in the figure below. These users could be human users or processes running on a computer system. Many users can be attached to the same service provider. Through this provider, each user must be able to exchange messages with any other user. To be able to deliver these messages, the service provider must be able to unambiguously identify each user. In computer networks, each user is identified by a unique **address**, we will Image Analysis: ### Localization and Attribution - **Image 1**: - Location: Center of the page. - Caption: "Figure 2.11: Anycast transmission" ### Object Detection and Classification #### Image 1: - **Objects Detected**: - Multiple computer nodes connected by lines, representing a network. - Labels indicating specific nodes (e.g., S, 1, 2, 3, 4, 5). - Dashed lines indicating possible data transmission paths. - A symbol (*) marking three specific nodes. ### Scene and Activity Analysis #### Image 1: - **Scene Description**: - The image illustrates a computer network using anycast transmission mode. - **Activity**: - A host sends data intended to be received by one of the receivers in the anycast group. - The network ensures that the data is delivered to the closest or optimal receiver among the specified group. ### Text Analysis - **Text on Page**: - Title: "Computer Networking: Principles, Protocols and Practice, Release 0.25" - Figure 2.11 caption explains anycast transmission. - Descriptive text about multicast transmission, with emphasis on the anycast transmission mode according to RFC 1542. - Example explaining the scenario in which network nodes marked with * are part of the anycast group. - Section title: "2.2 Services and protocols" - Explanation on the differences between a service and a protocol in computer networking. ### Diagram and Chart Analysis #### Image 1: - **Data Representation**: - Nodes labeled with letters and numbers. - Dashed lines and solid connections showing potential network paths. - **Key Insights**: - The dashed lines represent multiple possible routes for data delivery. - Solid connections leading to specific intermediate nodes based on optimal path selection. ### Color Analysis #### Image 1: - **Color Composition**: - Predominantly grayscale for the nodes' symbols. - Blue dashed and solid lines indicating network paths. - Red and black labels marking node identifiers and specific groups. ### Perspective and Composition #### Image 1: - **Perspective**: - The image uses a standard, straightforward perspective suitable for technical diagrams. - **Composition**: - Nodes are evenly distributed. - Connecting lines are clearly differentiated between primary and secondary paths, aiding in comprehension. ### Contextual Significance #### Image 1: - **Context**: - The image supports the textual explanation of different transmission modes in computer networks. - It provides a visual aid to better understand anycast transmission. ### Diagram Numbers - **Data Points**: - Nodes: S, 1, 2, 3, 4, 5 - Marked nodes (*): 1, 2, 4 - Intermediate nodes: 3 ### Textual Content - **Process Descriptions**: - The text provides an explanation and an example of anycast transmission where multiple receivers are in the same anycast group, and the network delivers the data to the closest group member. ### Tables - **Not Applicable**: No tables are present in the provided content. ### Anomaly Detection - **No noticeable anomalies**: The image and text appear consistent and appropriately formatted for the context of a technical document. ### Trend and Interpretation - **Trends**: - Anycast transmission ensures redundancy and optimizes data delivery paths based on network conditions and receiver proximity. This comprehensive examination aligns with the provided aspects and describes the key elements relevant to the visual content and its context. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 16 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Figure 2.12: Users and service provider Discuss later how these addresses are built and used. At this point, and when considering unicast transmission, the main characteristic of these addresses is that they are unique. Two different users attached to the network cannot use the same address. Throughout this book, we will define a service as a set of capabilities provided by a system (and its underlying elements) to its user. A user interacts with a service through a **service access point**. Note that as shown in the figure above, users interact with one service provider. In practice, the service provider is distributed over several hosts, but these are implementation details that are not important at this stage. These interactions between a user and a service provider are expressed in [X200] by using primitives, as shown in the figure below. These primitives are an abstract representation of the interactions between a user and a service provider. In practice, these interactions could be implemented as system calls, for example. ## Figure 2.13: The four types of primitives Four types of primitives are defined: - **X.request**. This type of primitive corresponds to a request issued by a user to a service provider. - **X.indication**. This type of primitive is generated by the network provider and delivered to a user (often related to an earlier and remote **X.request** primitive). - **X.response**. This type of primitive is generated by a user to answer to an earlier **X.indication** primitive. - **X.confirm**. This type of primitive is delivered by the service provider to confirm to a user that a previous **X.request** primitive has been successfully processed. Primitives can be combined to model different types of services. The simplest service in computer networks is called the **connectionless service**. This service can be modeled by using two primitives: - **Data.request(source,destination,SDU)**. This primitive is issued by a user that specifies, as parameters, the (source) address, the address of the recipient of the message and the message itself. We will use **Service Data Unit** (SDU) to name the message that is exchanged transparently between two users of a service. - **Data.indication(source,destination,SDU)**. This primitive is delivered by a service provider to a user. It contains as parameters a **Service Data Unit** as well as the addresses of the sender and the destination users. When discussing the service provided in a computer network, it is often useful to be able to describe the interactions between the users and the provider graphically. A frequently used representation is the time-sequence diagram. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 17 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 In this chapter and later throughout the book, we will often use diagrams such as the figure below. A time-sequence diagram describes the interactions between two users and a service provider. By convention, the users are represented in the left and right parts of the diagram while the service provider occupies the middle of the diagram. In such a time-sequence diagram, time flows from the top to the bottom of the diagram. Each primitive is represented by a plain horizontal arrow, to which the name of the primitive is attached. The dashed lines are used to represent the possible relationship between two (or more) primitives. Such a diagram provides information about the ordering of the different primitives, but the distance between two primitives does not represent a precise amount of time. The figure below provides a representation of the connectionless service as a time-sequence diagram. The user on the left, having address S, issues a `Data.request` primitive containing SDU M that must be delivered by the service provider to destination D. The dashed line between the two primitives indicates that the `Data.indication` primitive that is delivered to the user on the right corresponds to the `Data.request` primitive sent by the user on the left. ![A simple connectionless service](#) **Figure 2.14:** A simple connectionless service ## 2.2 Services and Protocols There are several possible implementations of the connectionless service, which we will discuss later in this book. Before studying these realizations, it is useful to discuss the possible characteristics of the connectionless service. ### Reliable Connectionless Service A **reliable connectionless service** is one where the service provider guarantees that all SDUs submitted in `Data.request` by a user will eventually be delivered to their destination. Such a service would be very useful for users, but guaranteeing perfect delivery is difficult in practice. For this reason, computer networks usually support an **unreliable connectionless service**. ### Unreliable Connectionless Service An **unreliable connectionless service** may suffer from various types of problems compared to a reliable connectionless service. First of all, an unreliable connectionless service does not guarantee the delivery of all SDUs. This can be expressed graphically by using the time-sequence diagram below. ![Time-sequence diagram for unreliable connectionless service](#) In practice, an unreliable connectionless service will usually deliver a large fraction of the SDUs. However, since the delivery of SDUs is not guaranteed, the user must be able to recover from the loss of any SDU. A second imperfection that may affect an unreliable connectionless service is that it may duplicate SDUs. Some unreliable connectionless service providers may deliver an SDU sent by a user twice or even more. This is illustrated by the time-sequence diagram below. ![Time-sequence diagram for duplicated SDUs](#) Finally, some unreliable connectionless service providers may deliver to a destination a different SDU than the one that was supplied in the `Data.request`. This is illustrated in the figure below. ![Time-sequence diagram for different SDUs](#) When a user interacts with a service provider, it must precisely know the limitations of the underlying service to be able to overcome any problem that may arise. This requires a precise definition of the characteristics of the underlying service. Another important characteristic of the connectionless service is whether it preserves the ordering of the SDUs. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 18 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Chapter 2: Part 1: Introduction ### Figures **Figure 2.15:** An unreliable connectionless service may lose SDUs | Source | Provider | Destination | |-------------------|---------------------|----------------------| | | | | | DATA.request(S, D, "Msg") | | | | | | | | | | | | | | | | | | | | | | | --- **Figure 2.16:** An unreliable connectionless service may duplicate SDUs | Source | Provider | Destination | |-------------------|---------------------|----------------------| | | | | | DATA.request(S, D, "Msg") | | | | | DATA.indication(S, D, "Msg") | | | | DATA.indication(S, D, "Msg") | | | | | | | | | | --- #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 19 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## 2.2. Services and Protocols **Figure 2.17:** An unreliable connectionless service may deliver erroneous SDUs. ``` Source Provider Destination | DATA.request(S, D, "Msg") | V DATA.indication(S, D, "XYZ") ``` Sent by one user. From the user's viewpoint, this is often a desirable characteristic. This is illustrated in the figure below. **Figure 2.18:** A connectionless service that preserves the ordering of SDUs sent by a given user. ``` Source Provider Destination | DATA.request(S, D, "A") | | DATA.request(S, D, "B") | V DATA.indication(S, D, "A") V DATA.indication(S, D, "B") ``` However, many connectionless services, and in particular the unreliable services, do not guarantee that they always preserve the ordering of the SDUs sent by each user. This is illustrated in the figure below. The connectionless service is widely used in computer networks as we will see later in this book. Several variations to this basic service have been proposed. One of these is the confirmed connectionless service. This service uses a `Data.confirm` primitive in addition to the classical `Data.request` and `Data.indication` primitives. This primitive is issued by the service provider to confirm to a user the delivery of a previously sent SDU to its recipient. Note that, like the registered service of the post office, the `Data.confirm` primitive only indicates that the SDU has been delivered to the destination user. The `Data.confirm` primitive does not indicate whether the SDU has been processed by the destination user. This confirmed connectionless service is illustrated in the figure below. The connectionless service we have described earlier is frequently used by users who need to exchange small SDUs. Users needing to either send or receive several different and potentially large SDUs, or who need structured exchanges often prefer the connection-oriented service. An invocation of the connection-oriented service is divided into three phases. The first phase is the establishment of a connection. A connection is a temporary association between two users through a service provider. Several Image Analysis: ### Comprehensive Examination of the Attached Visual Content #### 1. Localization and Attribution - **Image 1**: The first diagram detailing an unreliable connectionless service is placed at the top of the page. - **Image 2**: The second diagram illustrating a connectionless service that preserves the ordering of SDUs is located below the first image. #### 2. Object Detection and Classification - **Image 1**: - **Objects**: - Three sections: Source, Provider, and Destination. - Arrows indicating data flow. - Labels: "DATA.request(S, D, 'Msg')" and "DATA.indication(S, D, 'XYZ')". - **Key Features**: - The dashed arrow indicating an unreliable path. - The solid arrow representing the data delivery. - **Image 2**: - **Objects**: - Three sections similarly labeled as Source, Provider, and Destination. - Arrows showing ordered data flow. - Labels: "DATA.request(S, D, 'A')", "DATA.request(S, D, 'B')", "DATA.indication(S, D, 'A')", "DATA.indication(S, D, 'B')". - **Key Features**: - Sequential solid arrows indicating ordered data delivery. #### 3. Scene and Activity Analysis - **Image 1**: - **Scene**: Demonstrates an unreliable connectionless service where a message "Msg" requested from the source does not arrive correctly at the destination, resulting in data labeled "XYZ". - **Activities**: Data request and indication processes. - **Image 2**: - **Scene**: Illustrates a connectionless service that accurately delivers messages in the order they were sent. - **Activities**: Sequential data request and corresponding indication processes. #### 4. Text Analysis - **Text Detected**: - **Figure 2.17 Caption**: "An unreliable connectionless service may deliver erroneous SDUs". - **Figure 2.18 Caption**: "A connectionless service that preserves the ordering of SDUs sent by a given user". - **Main Text Analysis**: Explains the difference between unreliable and reliable connectionless services and their characteristics and importance. #### 5. Diagram and Chart Analysis - **Image 1 Analysis**: - **Axes and Labels**: No specific axes labeled but time is implied on the horizontal plane. - **Data Insights**: Unreliable data transfer where the content sent is different from the content received. - **Image 2 Analysis**: - **Axes and Labels**: Similar to Image 1, time is implied on the horizontal plane. - **Data Insights**: Ordered delivery of data from source to destination showing reliability. #### 8. Color Analysis - Both images primarily use black and white with clear text and arrows, making the diagrams easy to read and understand. The color scheme is kept minimalistic to focus on the content. #### 9. Perspective and Composition - **Perspective**: 2D planar view. - **Composition**: - **Image 1**: Elements arranged to show the concept of unreliable data transmission interactively. - **Image 2**: Elements arranged to illustrate the reliability of ordered data transmission clearly. #### 10. Contextual Significance - **Overall Document Theme**: Focused on principles and protocols in computer networking. - **Image Contribution**: Helps in understanding the distinction between different types of connectionless services and their functioning which is crucial in networking contexts. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 20 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Chapter 2: Part 1: Introduction ### Figure 2.19: A connectionless service that does not preserve the ordering of SDUs sent by a given user | Source | Provider | Destination | |---------|----------|--------------| | | | | | DATA.request(S, D, "A") | | | | DATA.request(S, D, "B") | | | | | | DATA.indication(S, D, "B") | | | | DATA.indication(S, D, "A") | --- ### Figure 2.20: A confirmed connectionless service | Source | Provider | Destination | |---------|----------|--------------| | | | | | DATA.request(S, D, "M") | | | | | DATA.confirm | | | | | DATA.indication(S, D, "M") | #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 21 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## 2.2. Services and Protocols Connections may exist at the same time between any pair of users. Once established, the connection is used to transfer SDUs. Connectors usually provide one bidirectional stream supporting the exchange of SDUs between the two users that are associated through the **connection**. This stream is used to transfer data during the second phase of the connection called the **data transfer phase**. The third phase is the termination of the connection. Once the users have finished exchanging SDUs, they request to the service provider to terminate the connection. As we will see later, there are also some cases where the service provider may need to terminate a connection itself. The establishment of a connection can be modeled by using four primitives: **Connect.request**, **Connect.indication**, **Connect.response**, and **Connect.confirm**. The **Connect.request** primitive is used to request the establishment of a connection. The main parameter of this primitive is the address of the destination user. The service provider delivers a **Connect.indication** primitive to inform the destination user of the connection attempt. If it accepts to establish a connection, it responds with a **Connect.response** primitive. At this point, the connection is considered to be open and the destination user can start sending SDUs over the connection. The service provider processes the **Connect.response** and will deliver a **Connect.confirm** to the user who initiated the connection. The delivery of this primitive terminates the connection establishment phase. At this point, the connection is considered to be open and both users can send SDUs. A successful connection establishment is illustrated below. ``` Source Provider Destination CONNECT.request CONNECT.indication --------------- CONNECT.response CONNECT.confirm Time ``` *Figure 2.21: Connection establishment* The example above shows a successful connection establishment. However, in practice, not all connections are successfully established. One reason is that the destination user may not agree, for policy or performance reasons, to establish a connection with the initiating user at this time. In this case, the destination user responds to the **Connect.indication** primitive by a **Disconnect.request** primitive that contains a parameter to indicate why the connection has been refused. The service provider will then deliver a **Disconnect.indication** primitive to inform the initiating user. A second reason is when the service provider is unable to reach the destination user. This might happen because the destination user is not currently attached to the network or due to congestion. In these cases, the service provider responds to the **Connect.request** with a **Disconnect.indication** primitive whose reason parameter contains additional information about the failure of the connection. Once the connection has been established, the service provider supplies two data streams to the communicating users. The first data stream can be used by the initiating user to send SDUs. The second data stream allows the responding user to send SDUs to the initiating user. The data streams can be organized in different ways. A first organization is the **message-mode transfer**. With the message-mode transfer, the service provider guarantees that one and only one **Data.indication** will be delivered to the endpoint of the data stream for each **Data.request** primitive issued by the other endpoint. The message-mode transfer is illustrated in the figure below. The main advantage of the **message-transfer mode** is that the recipient receives exactly the SDUs that were sent by the other user. If each SDU contains a command, the receiving user can process each command as soon as it receives a SDU. Unfortunately, the **message-mode transfer** is not widely used on the Internet. On the Internet, the most popular... #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 22 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Chapter 2: Part 1: Introduction ### Figure 2.22: Two types of rejection for a connection establishment attempt | Source | Provider | Destination | |----------------------|-----------------------|----------------------| | `CONNECT.request` | | `CONNECT.indication` | | | | `DISCONNECT.request` | | | | **Connection rejected by destination** | | `DISCONNECT.indication` | | | | `CONNECT.request` | | | | | `DISCONNECT.indication` | | | | | **Connection rejected by provider** | | **Time** | | | --- ### Figure 2.23: Message-mode transfer in a connection oriented service | Source | Provider | Destination | |----------------------|-----------------------|----------------------| | `CONNECT.request` | | `CONNECT.indication` | | | | `CONNECT.response` | | | `CONNECT.confirm` | | | `DATA.request("A")` | | `DATA.indication("A")` | | `DATA.request("B")` | | `DATA.indication("B")` | | `DATA.request("C")` | | `DATA.indication("C")` | | **Time** | | | #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 23 Context: connection-oriented service transfers SDUs in stream-mode. With the stream-mode, the service provider supplies a byte stream that links the two communicating users. The sending user sends bytes by using `Data.request` primitives that contain sequences of bytes as SDUs. The service provider delivers SDUs containing consecutive bytes to the receiving user by using `Data.indication` primitives. The service provider ensures that all the bytes sent at one end of the stream are delivered correctly in the same order at the other endpoint. However, the service provider does not attempt to preserve the boundaries of the SDUs. There is no relation enforced by the service provider between the number of `Data.request` and the number of `Data.indication` primitives. The stream-mode is illustrated in the figure below. In practice, a consequence of utilizing the stream-mode is that if the users want to exchange structured SDUs, they will need to provide the mechanisms that allow the receiving user to separate successive SDUs in the byte stream that it receives. As we will see in the next chapter, application layer protocols often use specific delimiters such as the end of line character to delineate SDUs in a byte stream. ``` Figure 2.24: Stream-mode transfer in a connection-oriented service ``` | Source | Provider | Destination | |----------------|-------------|--------------------| | CONNECT.request | | | | CONNECT.indication | | | | CONNECT.response | | | | DATA.request("AB") | | DATA.indication("A")| | DATA.request("CD") | | DATA.indication("B")| | DATA.request("EF") | | DATA.indication("C")| | | | DATA.indication("D")| The third phase of a connection is when it needs to be released. A connection involves three parties (two users and one service provider), and only one of them can request the termination of the connection. Usually, connections are terminated upon request of one user once the data transfer is finished. However, sometimes the service provider may be forced to terminate a connection. This can be due to lack of resources inside the service provider or because one of the users is not reachable anymore through the network. In this case, the service provider will use `Disconnect.indication` primitives to both users. These primitives will contain, as a parameter, some information about the reason for the termination of the connection. Unfortunately, as illustrated in the figure below, when a service provider is forced to terminate a connection it cannot guarantee that all SDUs sent by each user have been delivered to the other user. This connection release is said to be abrupt as it can cause losses of SDUs. An abrupt connection release can also be triggered by one of the users. If a user needs, for any reason, to terminate a connection quickly, it can issue a `Disconnect.request` primitive and request an abrupt release. The service provider will process the request, stop the two data streams and deliver the `Disconnect.indication` primitive to the remote user as soon as possible. As illustrated in the figure below, this abrupt connection release may cause losses of SDUs. To ensure a reliable delivery of the SDUs sent by each user, we need to consider the two streams that compose a connection as independent. A user should be able to release the stream that it uses to send SDUs once it has sent all the SDUs that it planned to send over this connection, but still continue to receive SDUs over the opposite stream. This graceful connection release is usually performed as shown in the figure below. One user issues a `Disconnect.request` primitive to its provider once it has issued all its `Data.request` primitives. The service provider will wait until all `Data.indication` primitives have been delivered to the receiving user before issuing the `Disconnect.indication` primitive. This primitive informs the receiving user that it will no longer receive SDUs over this connection, but it is still able to issue `Data.request` primitives on the stream in the opposite direction. Once the user has issued all of its `Data.request` primitives, it issues a `Disconnect.request` primitive to request the termination of the remaining stream. The service provider will process the request and deliver the corresponding #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 24 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Chapter 2: Part 1: Introduction ### Figure 2.25: Abrupt connection release initiated by the service provider | Source | Provider | Destination | |--------------------------|----------|--------------------------| | Connection opened | | Connection opened | | DATA.request("A") | | DATA.indication("A") | | DATA.request("B") | | DATA.indication("C") | | | | | | DISCONNECT.indication | | DISCONNECT.indication | | **Time** | | **Time** | ### Figure 2.26: Abrupt connection release initiated by a user | Source | Provider | Destination | |--------------------------|----------|--------------------------| | Connection opened | | Connection opened | | DATA.request("A") | | DATA.indication("A") | | DATA.request("B") | | DATA.request("C") | | | | | | DISCONNECT.req(abrupt) | | | | **Time** | | **Time** | #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 25 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 Disconnect.indication to the other user once it has delivered all the pending Data.indication primitives. At this point, all data has been delivered and the two streams have been released successfully and the connection is completely closed. ![Figure 2.27: Graceful connection release](#) --- **Note:** Reliability of the connection-oriented service An important point to note about the connection-oriented service is its reliability. A connection-oriented service can only guarantee the correct delivery of all SDUs provided that the connection has been released gracefully. This implies that while the connection is active, there is no guarantee for the actual delivery of the SDUs exchanged as the connection may need to be released abruptly at any time. ## 2.3 The reference models Given the growing complexity of computer networks, during the 1970s network researchers proposed various reference models to facilitate the description of network protocols and services. Of these, the Open Systems Interconnection (OSI) model [Zimmermann80] was probably the most influential. It served as the basis for the standardisation work performed within the ISO to develop global computer network standards. The reference model that we use in this book can be considered as a simplified version of the OSI reference model. ### 2.3.1 The five layers reference model Our reference model is divided into five layers, as shown in the figure below. Starting from the bottom, the first layer is the Physical Layer. Two communicating devices are linked through a physical medium. This physical medium is used to transfer an electrical or optical signal between two directly connected devices. Several types of physical mediums are used in practice: - **Electrical cable:** Information can be transmitted over different types of electrical cables. The most common ones are the twisted pairs that are used in the telephone network, but also in enterprise networks and coaxial cables. Coaxial cables are still used in cable TV networks, but are no longer used in enterprise networks. - **Optical fiber:** Optical fibers are frequently used in public and enterprise networks when the distance between the communication devices is larger than one kilometer. There are two main types of optical fibers. *A more interesting historical discussion of the OSI-TCP/IP debate may be found in [Russell60].* ## 2.3 The reference models 21 #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 26 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Chapter 2: Part 1: Introduction ### Figure 2.28: The five layers of the reference model ``` Application Transport Network Datalink Physical ``` #### Physical transmission medium Multimode and monomode: Multimode is much cheaper than monomode fiber because a LED can be used to send a signal over a multimode fiber while a monomode fiber must be driven by a laser. Due to the different modes of propagation of light, monomode fibers are limited to distances of a few kilometers while multimode fibers can be used over distances greater than several tens of kilometers. In both cases, repeaters can be used to regenerate the optical signal at one endpoint of a fiber to send it over another fiber. - **Wireless**: In this case, a radio signal is used to encode the information exchanged between the communicating devices. Many types of modulation techniques are used to send information over a wireless channel and there is a lot of innovation in this field with new techniques appearing every year. While most wireless networks rely on radio signals, some use a laser that sends light pulses to a remote detector. These optical techniques allow to create point-to-point links while radio-based techniques, depending on the directionality of the antennas, can be used to build networks containing devices spread over a small geographical area. An important point to note about the Physical layer is the service that it provides. This service is usually an unreliable connection-oriented service that allows the users of the Physical layer to exchange bits. The unit of information transfer in the Physical layer is the bit. The Physical layer service is unreliable because: - The Physical layer may change, e.g., due to electromagnetic interferences, the value of a bit being transmitted may not be received correctly. - The Physical layer may deliver **more bits** to the receiver than the bits sent by the sender. - The Physical layer may deliver **fewer bits** to the receiver than the bits sent by the sender. The last two points may seem strange at first glance. When two devices are attached through a cable, how is it possible for bits to be created or lost on such a cable? This is mainly due to the fact that the communicating devices use their own clock to transmit bits at a given bit rate. Consider a sender having a clock that ticks one million times per second and sends one bit every tick. Every microsecond, the sender sends an electrical or optical signal that encodes one bit. The sender's bit rate is thus 1 Mbps. If the receiver clock ticks exactly **every** microsecond, it will also deliver 1 Mbps to its receiver. If the receiver's clock is slightly faster (e.g., slower), than it will deliver slightly more (resp. less) than one million bits every second. This explains why the physical layer may lose or create bits. **Note: Bit Rate** In computer networks, the bit rate of the physical layer is always expressed in bits per second. One Mbps is one million bits per second and one Gbps is one billion bits per second. This is in contrast with memory specifications that are usually expressed in bytes (B), Kilobytes (1024 bytes) or MegaBytes (1048576 bytes). Thus transferring one MByte through a 1 Mbps link lasts 8.39 seconds. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 27 Context: # Computer Networking : Principles, Protocols and Practice, Release 0.25 ## 2.3. The reference models | Bit rate | Bits per second | |----------|-----------------| | 1 Kbps | 10³ | | 1 Mbps | 10⁶ | | 1 Gbps | 10⁹ | | 1 Tbps | 10¹² | **Figure 2.29: The Physical layer** The physical layer allows two or more entities that are directly attached to the same transmission medium to exchange bits. Being able to exchange bits is important as virtually any information can be encoded as a sequence of bits. Electrical engineers are used to processing streams of bits, but computer scientists usually prefer to deal with higher-level concepts. A similar issue arises with file storage. Storage devices such as hard-disks also store streams of bits. There are hardware devices that process the bit stream produced by a hard-disk, but computer scientists have designed file systems to allow applications to easily access such storage devices. These file systems are typically divided into several layers as well. Hard-disks store sectors of 512 bytes or more. Unix filesystems group sectors in larger blocks that can contain data or inodes representing the structure of the filesystem. Finally, applications manipulate files and directories that are translated in blocks, sectors and eventually bits by the operating system. Computer networks use a similar approach. Each layer provides a service that is built above the underlying layer and is closer to the needs of the applications. The **Data link layer** builds on the service provided by the underlying physical layer. The Data link layer allows two hosts that are directly connected through the physical layer to exchange information. The unit of information exchanged between two entities in the Data link layer is a **frame**. A frame is a finite sequence of bits. Some Data link layers use variable-length frames while others only use fixed-length frames. Some Data link layers provide a connection-oriented service while others provide a connectionless service. Some Data link layers provide reliable delivery while others do not guarantee the correct delivery of the information. An important point to note about the **Data link layer** is that although the figure below indicates that two entities of the Data link layer exchange frames directly, in reality this is slightly different. When the Data link layer entity on the left needs to transmit a frame, it issues as many Data.request primitives to the underlying physical layer as there are bits in the frame. The physical layer will then convert the sequence of bits in an electromagnetic or optical signal that will be sent over the physical medium. The physical layer on the right hand side of the figure will decode the received signal, recover the bits and issue the corresponding Data.indication primitives to its Data link layer entity. If there are no transmission errors, this entity will receive the frame sent earlier. **Figure 2.30: The Data link layer** The **Data link layer** allows directly connected hosts to exchange information, but it is often necessary to exchange information between hosts that are not attached to the same physical medium. This is the task of the **network layer**. The network layer is built above the Data link layer. Network layer entities exchange packets. A **packet** is a finite sequence of bytes that is transported by the data link layer inside one or more frames. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 28 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 The content of this section discusses networking, particularly the information pertaining to its origin and destination, as well as how it traverses through various intermediate devices known as routers from its origin to its destination. ![Figure 2.31: The network layer](https://www.example.com/image1.jpg) ``` Network Packets Network Packets Network Datalink Datalink Datalink Datalink Datalink Physical Physical Physical Physical Physical ``` Most realizations of the network layer, including the internet, do not provide a reliable service. However, many applications need to exchange information reliably, and using the network layer service directly would be very difficult for them. Ensuring the reliable delivery of the data produced by applications is the task of the **transport layer**. The transport layer entities exchange **segments**. A segment is a finite sequence of bytes that are transported inside one or more packets. A transport layer entity issues segments (or sometimes parts of segments) as requests to the underlying network layer entity. There are different types of transport layers. The most widely used transport layers on the Internet are TCP, which provides a reliable connection-oriented byte stream transport service, and UDP, which provides an unreliable connection-less transport service. ![Figure 2.32: The transport layer](https://www.example.com/image2.jpg) ``` Transport Segments Transport Network Network Network Datalink Datalink Datalink Physical Physical Physical ``` The upper layer of our architecture is the **Application layer**. This layer includes all the mechanisms and data structures that are necessary for the applications. We will use Application Data Unit (ADU) to indicate the data exchanged between two entities of the Application layer. ![Figure 2.33: The Application layer](https://www.example.com/image3.jpg) ``` Application ADU Application Transport Transport Network Network Datalink Datalink Physical Physical ``` ## 2.3.2 The TCP/IP reference model In contrast with OSI, the TCP/IP community did not spend a lot of effort defining a detailed reference model; in fact, the goals of the Internet architecture were only documented after TCP/IP had been deployed (Clark88). RFC 1122, which defines the requirements for Internet hosts, mentions four different layers. Starting from the top, these are: 1. Application layer 2. Transport layer 3. Internet layer, which is equivalent to the network layer of our reference model 4. Link layer, which combines the functionalities of the physical and datalink layers of our five-layer reference model Besides this difference in the lower layers, the TCP/IP reference model is very close to the five layers that we use throughout this document. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 29 Context: # 2.3 The reference models ## 2.3.3 The OSI reference model Compared to the five layers reference model explained above, the OSI reference model defined in [X200] is divided into seven layers. The four lower layers are similar to the four lower layers described above. The OSI reference model refined the application layer by dividing it into three layers: - **Session layer:** The Session layer contains the protocols and mechanisms that are necessary to organize and to synchronize the dialogue and to manage the data exchange of presentation layer entities. While one of the main functions of the transport layer is to cope with the unreliability of the network layer, the session’s layer objective is to hide the possible failures of transport-level connections to the upper layer higher. For this, the Session Layer provides services that allow to establish a session-connection, to support orderly data exchange (including mechanisms that allow to recover from the abrupt release of an underlying transport connection), and to release the connection in an orderly manner. - **Presentation layer:** The Presentation layer was designed to cope with the different ways of representing information on computers. There are many differences in the way computer store information. Some computers store integers as 32 bits field, others use 64 bits field and the same problem arises with floating point number. For textual information, this is even more complex with the many different character codes that have been used. To solve this problem, the Presentation layer contains provisions for a common representation of the data transferred. The ASN.1 notation was designed for the Presentation layer and is still used today by some protocols. - **Application layer:** The Application layer contains the mechanisms that do not fit in neither the Presentation nor the Session layer. The OSI Application layer was itself further divided in several generic service elements. **Note:** Where are the missing layers in TCP/IP reference model? The TCP/IP reference places the Presentation and the Session layers implicitly in the Application layer. The main motivations for simplifying the upper layers in the TCP/IP reference model were pragmatic. Most Internet applications started as prototypes that evolved and were later standardized. Many of these applications assumed that they would be used to exchange information written in American English and for which the 7-bit US-ASCII character code was sufficient. This was the case for email, but as we'll see in the next chapter, email was able to evolve to support different character encodings. Some applications considered the different data representations explicitly. For example, FTP contained mechanisms to convert a file from one format to another and the HTML language was defined to represent web pages. On the other hand, many ISO specifications were developed by committees composed of people who did not all participate in actual implementations. ISO spent a lot of effort analysing the requirements and defining a solution that meets all of these requirements. Unfortunately, some of the specifications were so complex that it was difficult to implement them completely and the standardization bodies defined recommended profiles that contained the implemented sets of options... | Application Layer | ADU | Presentation | Session | Transport | Network | Datalink | Physical Layer | |-------------------|-----|--------------|---------|-----------|---------|----------|-----------------| | | | | | | | | | Figure 2.34: The seven layers of the OSI reference model > 6 There is now a rough consensus for the greater use of the Unicode character format. Unicode can represent more than 100,000 different characters from the known written languages on Earth. Maybe one day, all computers will only use Unicode to represent all their stored characters and Unicode could become the standard format to exchange characters, but we are not yet at this stage today. 2.3. The reference models 25 Image Analysis: ### 1. Localization and Attribution: - **Image 1**: Located in the lower half of the page. - **Text Block**: Above the image, spans the top three-quarters of the page. ### 2. Object Detection and Classification: - **Image 1:** Diagram of the OSI reference model. - **Objects Detected:** - Boxes labeled with different layers (Application, Presentation, Session, Transport, Network, DataLink, Physical). - Arrows connecting the boxes, indicating the hierarchical structure. ### 3. Scene and Activity Analysis: - **Image 1:** Depicts a visual representation of the OSI model in the form of vertically stacked layers. - **Actors:** None (diagrammatic illustration). - **Actions:** N/A ### 4. Text Analysis: - **Text Block above Image:** Explanation of the OSI reference model. - It outlines the seven layers of the OSI model, explaining functions and significance. - It differentiates between Session, Presentation, and Application layers. - Discusses the complexities and techniques involved in these layers. ### 5. Diagram and Chart Analysis: - **Image 1:** Diagram is a clear and structured representation of the seven layers of the OSI model. - **Axes, Scales, and Legends:** - No specific axes or scales since it's a diagram. - Labels for each layer serve as legends. - **Key Insights:** - Visual division of complex networking functions into distinct layers. - Illustration of how layers interact and rely on each other. - Demonstrates the OSI model's structure for facilitating different networking functions. ### 8. Color Analysis: - **Image 1:** - **Dominant Colors:** - Blue for arrows and some text. - Black for the majority of the text. - Grey for boxes. - **Impact:** - Use of blue helps in distinguishing between the descriptive text and the titles of each layer, enhancing clarity. - Grey boxes separate the layers, making the hierarchical structure visually clear. ### 9. Perspective and Composition: - **Image 1:** - **Perspective:** - Straight-on view makes all layers equally visible. - **Composition:** - Layered diagram with boxes stacked vertically and connected by arrows. - Text adjacent to the boxes providing layer names and descriptions. ### 10. Contextual Significance: - **Text and Image Combined:** - Both work together to provide a theoretical overview of the OSI model in computer networking. - Diagram serves as a visual aid to the detailed textual explanation above it. - Contributes to the understanding of how data communication protocols are structured. ### 13. Graph Numbers: - **Image 1:** - Layers: 7 layers represented (Application, Presentation, Session, Transport, Network, DataLink, Physical). #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 30 Context: ```markdown ## 2.4 Organisation of the book This document is organised according to the **TCP/IP** reference model and follows a top-down approach. Most of the classical networking textbooks chose a bottom-up approach; i.e., they first explained all the electrical and optical details of the physical layer then moved to the datalink layer. This approach worked well during the infancy of computer networks and until the late 1990s. At that time, most students were not users of computer networks and it was useful to explain computer networks by building the corresponding protocols from the simplest, in the physical layer, up to the application layer. Today, all students are active users of Internet applications, and starting to learn computer networking by looking at this is not very motivating. Starting from [KuroseRoss09](#), many textbooks and teachers have chosen a top-down approach. This approach starts from applications such as email and web that students already know and explores the different layers, starting from the application layer. This approach works quite well with today’s students. The traditional bottom-up approach could in fact be considered as an engineering approach as it starts from the simple network that allows the exchange of bits, and explains how to combine different protocols and mechanisms to build the most complex applications. The top-down approach could on the other hand be considered as a scientific approach. Like biologists, it starts from an existing (man-built) system and explores it layer by layer. Besides the top-down versus bottom-up organisation, computer networking books can either aim at having an in-depth coverage of a small number of topics, or at having a limited coverage of a wide range of topics. For a wide range of topics is interesting for introductory courses or for students who do not need a detailed knowledge of computer networks. It allows the students to learn a little about everything and then start from this base knowledge later if they need to understand computer networking in more detail. This book seeks to cover, in detail, a smaller number of topics than other textbooks. This is motivated by the fact that computer networks often need to be pushed to their limits. Understanding the details of the main networking protocols is important to be able to fully grasp how a network behaves or extend it to provide innovative services. The book is organised as follows: We first describe the application layer in the **Application Layer** chapter. Given the large number of Internet-based applications, it is of course impossible to cover them all in detail. Instead, we focus on three types of Internet-based applications. We first study the Domain Name System (DNS) and then explain some of the protocols involved in the exchange of electronic mail. The discussion of the application layer ends with a description of the key protocols of the world wide web. All the applications rely on the transport layer that is explained in chapter **Transport**. This is a key layer in today’s networks as it contains all the mechanisms necessary to provide a reliable delivery of data over an unreliable network. We cover the transport layer by first developing a simple reliable transport layer protocol and then explain the details of the TCP and UDP protocols used in **TCP/IP** networks. After the transport layer, we analyse the network layer in chapter **Network Layer**. This is also a very important layer as it is responsible for the delivery of packets from any source to any destination through intermediate routers. In the network layer, we describe the two possible organisations of the network layer and the routing protocols based on link-state and distance vectors. Then we explain in detail the IPv4, IPv6, RIP, OSPF and BGP protocols that are actually used in today’s Internet. The last chapter of the book is devoted to the datalink layer. In chapter **Datalink Layer** and the **Local Area Networks**, we begin by explaining the principles of the datalink layers on point-to-point links. Then, we focus on the Local Area Networks. We first describe the Medium Access Control algorithms that allow multiple hosts to share one transmission medium. We consider both opportunistic and deterministic techniques. We then explain in detail two types of LANs that are important from a deployment viewpoint today: Ethernet and WiFi. > A popular quote says, *the devil is in the details*. This quote reflects very well the operation of many network protocols, where the change of a single bit may have huge consequences. In computer networks, understanding all the details is sometimes necessary. ``` #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 31 Context: # CHAPTER 3 ## Part 2: The Application Layer ### 3.1 The Application Layer The Application Layer is the most important and most visible layer in computer networks. Applications reside in this layer and human users interact with those applications through the network. In this chapter, we first briefly describe the main principles of the application layer and focus on the two most important application models: the client-server and the peer-to-peer models. Then, we review in detail two families of protocols that have proved to be very useful in the Internet: electronic mail and the protocols that allow access to information on the World Wide Web. We also describe the Domain Name System that allows humans to use user-friendly names while the hosts use 32 bits or 128 bits long IP addresses. ### 3.2 Principles The two important models used to organize a networked application are the client-server model and the peer-to-peer model. The first and oldest model is the client-server model. In this model, a server provides services to clients that exchange information with it. This model is highly asymmetrical: clients send requests and servers perform actions and return responses. It is illustrated in the figure below. ``` Client Queries Server |-------------------------->| |<--------------------------| Responses ``` **Service provider ("the network")** **Figure 3.1:** The client-server model The client-server model was the first model to be used to develop networked applications. This model comes naturally from the mainframes and minicomputers that were the only networked computers used until the 1980s. A minicomputer is a multi-user system that is used by tens or more users at the same time. Each user interacts with the minicomputer by using a terminal. Those terminals were mainly a screen, a keyboard, and a cable directly connected to the minicomputer. There are various types of servers as well as various types of clients. A web server provides information in response to the query sent by its clients. A print server prints documents sent as queries by the client. An email server will forward towards their recipient the email messages sent as queries while a music server will deliver the music requested by the client. From the viewpoint of the application developer, the client and the server interact in a defined manner. Image Analysis: ### Image Analysis #### 1. Localization and Attribution: - **Image Location:** The image is located towards the bottom half of the page. - **Image Number:** Image 1. #### 2. Object Detection and Classification: - **Objects Detected:** - Text blocks - Diagram - **Classification:** - Text falls under the category of documentation or instructional text. - The diagram is classified as a schematic or flowchart displaying a client-server model. #### 3. Scene and Activity Analysis: - **Scene Description:** - The page contains chapter 3 of a document, discussing the application layer in computer networks. - There is a heading indicating the focus on "Part 2: The Application Layer." - The content provides an introduction to the application layer with a focus on its importance, principles, and models. - Below the text, there is a diagram labeled "Figure 3.1" which represents the client-server model in a networked environment. #### 4. Text Analysis: - **Text Extracted:** - "CHAPTER 3" - "Part 2: The Application Layer" - "3.1 The application Layer" - "3.2 Principles" - Various paragraphs explaining the application layer and client-server model. - **Content Analysis:** - The text describes the application layer as an essential part of computer networks where applications reside. - Highlights two primary models: client-server and peer-to-peer. - Discusses principles and functionalities, including a diagram of the client-server model. #### 5. Diagram and Chart Analysis: - **Diagram Analysis:** - The diagram labeled "Figure 3.1: The client-server model" illustrates a network interaction. - It shows a client sending queries to a server, with the server sending back responses. - The entities involved (client, server, and service provider) are depicted in boxes connected by arrows indicating the flow of queries and responses. #### 8. Color Analysis: - **Color Composition:** - The page primarily uses black text on a white background. - Headings are in blue, providing contrast and visual hierarchy. - The diagram uses blue and red, enhancing clarity in representing different components and flows. #### 9. Perspective and Composition: - **Perspective:** - The perspective is straight-on, typical for reading text and viewing diagrams in a document. - **Composition:** - The text is organized into sections with clear headings. - The diagram is centrally placed below the relevant section, ensuring ease of reference. ### Additional Aspects: #### Ablaufprozesse (Process Flows): - The client-server interaction is detailed, illustrating the flow of information from the client (queries) to the server (responses). #### Prozessbeschreibungen (Process Descriptions): - Detailed description of how the client-server model works, emphasizing the roles of different servers (e.g., web server, print server). ### Conclusion: This image represents a page from a technical document discussing the application layer in computer networks. The text explains the importance and principles of the application layer, focusing on the client-server model, which is visually represented in a diagram for clarity. The structured composition and color use enhance readability and comprehension. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 32 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 Server applications directly exchange messages (the horizontal arrows labeled Queries and Responses in the above figure), but in practice these messages are exchanged thanks to the underlying layers (the vertical arrows in the above figure). In this chapter, we focus on these horizontal exchanges of messages. Networked applications do not exchange random messages. In order to ensure that the server is able to understand the queries sent by a client, and also that the client is able to understand the responses sent by the server, they must both agree on a set of syntactical and semantic rules. These rules define the format of the messages exchanged as well as their ordering. This set of rules is called an **application-level protocol**. An application-level protocol is similar to a structured conversation between humans. Assume that Alice wants to know the current time but does not have a watch. If Bob passes close by, the following conversation could take place: - **Alice**: Hello - **Bob**: Hello - **Alice**: What time is it? - **Bob**: 11:55 - **Alice**: Thank you - **Bob**: You're welcome Such a conversation succeeds if both Alice and Bob speak the same language. If Alice meets Tchang who only speaks Chinese, she won't be able to ask him the current time. A conversation between humans can be more complex. For example, assume that Bob is a security guard whose duty is to only allow trusted secret agents to enter a meeting room. If all agents know a secret password, the conversation between Bob and Trudy could be as follows: - **Bob**: What is the secret password? - **Trudy**: 1234 - **Bob**: This is the correct password, you're welcome If Alice wants to enter the meeting room but does not know the password, her conversation could be as follows: - **Bob**: What is the secret password? - **Alice**: 3.1415 - **Bob**: This is not the correct password. Human conversations can be very formal, e.g., when soldiers communicate with their hierarchy, or informal such as when friends discuss. Computers that communicate are more akin to soldiers and require well-defined rules to ensure an effective exchange of information. There are two types of rules that define how information can be exchanged between computers: 1. **Syntactical rules** that precisely define the format of the messages that are exchanged. As computers only process bits, the syntactical rules specify how information is encoded as bit strings. 2. **Organisation of the information flow**. For many applications, the flow of information must be structured and there are precedence relationships between the different types of information. In the time example above, Alice must greet Bob before asking for the current time. Alice would not ask for the current time first and greet Bob afterwards. Such precedence relationships exist in networked applications as well. For example, a server must receive a username and a valid password before accepting more complex commands from its clients. Let us discuss the syntactical rules. We will later explain how the information flow can be organised by analysing real networked applications. Application-layer protocols exchange two types of messages. Some protocols such as those used to support electronic mail exchange messages expressed as strings or lines of characters. As the transport layer allows hosts to exchange bytes, they need to agree on a common representation of the characters. The first and simplest method to encode characters is to use the **ASCII** table. RFC 20 provides the ASCII table that is used by many protocols on the Internet. For example, the table defines the following binary representations: #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 33 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 - A : `1000011b` - O : `0100000b` - z : `1110010b` - a : `1100001b` - space : `0010000b` In addition, the ASCII table also defines several non-printable or control characters. These characters were designed to allow an application to control a printer or a terminal. These control characters include CR and LF, that are used to terminate a line, and the Bell character which causes the terminal to emit a sound. - carriage return (CR) : `0001100b` - line feed (LF) : `0001010b` - Bell : `0000111b` The ASCII characters are encoded as a seven bits field, but transmitted as an eight-bits byte whose high order bit is usually set to 0. Bytes are always transmitted starting from the high order or most significant bit. Most applications exchange strings that are composed of fixed or variable numbers of characters. A common solution to define the character strings that are acceptable is to define them as a grammar using a Backus-Naur Form (BNF) such as the Augmented BNF defined in RFC 5234. A BNF is a set of production rules that generate all valid character strings. For example, consider a networked application that uses two commands, where the user can supply a username and a password. The BNF for this application could be defined as shown in the figure below. ``` command ::= usernamecommand | passwordcommand usernamecommand ::= "user" SP username passwordcommand ::= "pass" SP password username ::= ALPHA *(ALPHA | DIGIT | "-") password ::= 1*CHAR SP ::= " " ALPHA ::= %x41-5A | %x61-7A DIGIT ::= %x30-39 CHAR ::= %x21 | %x23-27 | %x2A-2B | %x2D-2E | %x30-39 | %x41-5A | %x61-7A ``` **Figure 3.2:** A simple BNF specification The example above defines several terminals and two commands: `usernamecommand` and `passwordcommand`. The `ALPHA` terminal contains all letters in upper and lower case. In the `ALPHA` rule, %x41 corresponds to ASCII character code 41 in hexadecimal, i.e., capital A. The CR and LF terminals correspond to the carriage return and linefeed control characters. The CRLF rule concatenates these two terminals to match the standard end of line termination. The `DIGIT` terminal contains all digits. The SP terminal corresponds to the whitespace characters. The `username` is composed of two strings separated by whitespace. In the ABNF rules that define the messages used by Internet applications, the commands are case-insensitive. The rule `user` corresponds to all possible cases of the letters that compose the word between brackets, e.g., `user`, `User`, `USER`, etc. A username contains at least one letter and up to 8 letters. User names are case-sensitive as they are not defined as a string between brackets. The `password` rule indicates that a password starts with a letter and can contain any number of letters or digits. The whitespace and the control characters cannot appear in a password defined by the above rule. Besides character strings, some applications also need to exchange 16 bits and 32 bits fields such as integers. A naive solution would have been to send the 16- or 32-bits field as it is encoded in the host's memory. Unfortunately, there are different methods to store 16- or 32- bits fields in memory. Some CPUs store the most significant byte of a 16-bits field in the first address of the field while others store the least significant byte at this location. When networked applications running on different CPUs exchange 16 bits fields, there are two possibilities to transfer them over the transport service: - send the most significant byte followed by the least significant byte - send the least significant byte followed by the most significant byte ## 3.2 Principles 29 Image Analysis: ### Comprehensive Examination of Visual Content #### 1. Localization and Attribution - **Image 1**: Located near the middle of the page, containing a textual section and a diagram labeled as "Figure 3.2." #### 2. Object Detection and Classification - **Image 1** includes: - Textual paragraphs - A diagram titled "Figure 3.2: A simple BNF specification," displaying a table with specifications and examples - Bulleted lists #### 3. Scene and Activity Analysis - **Image 1** depicts an explanation and specification of elements related to ASCII codes and BNF (Backus-Naur Form) grammar rules. The textual content is technical, aimed at explaining encoding and command specifications. #### 4. Text Analysis - **Image 1** contains the following significant text: - **ASCII codes definition**: Details ASCII codes for characters such as "A," "0," "z," carriage return (CR), line feed (LF), and Bell. - **BNF (Backus-Naur Form) specification**: Describes an example of BNF for commands like `usernamecommand` and `passwordcommand`. - **Procedures**: Details on how to send significant bytes. - Significance: This text serves to educate readers on how ASCII codes and BNF grammar are structured and used in computer networking. #### 5. Diagram and Chart Analysis - **Figure 3.2** details a simple BNF specification: - **Axes, scales, and legends**: Not applicable as it is a formal specification table and not a graphical chart. - **Key insights**: The diagram illustrates how to define commands and syntax rules using ABNF (Augmented BNF) for network applications. #### 6. Product Analysis - Not applicable; no products depicted. #### 7. Anomaly Detection - No apparent anomalies detected in the visual content. #### 8. Color Analysis - **Image 1**: Dominant colors are black text on a white background, with headings or diagrams possibly using bold text for emphasis. This color scheme is typical for technical documentation, ensuring clarity and readability. #### 9. Perspective and Composition - **Image 1**: The perspective is a standard frontal view typical of printed documentation. - The text is arranged in consistent formatting with headings and a diagram aligned centrally for easy reading. #### 10. Contextual Significance - **Image 1**: Contributes to a larger body of work focused on computer networking principles. Specifically, it provides detailed examples and explanations regarding ASCII encoding and command syntax, aiding the reader's understanding of protocol and practice. #### 13. Graph Numbers - Not applicable; no graphs with numerical data presented. #### **Ablaufprozesse (Process Flows)** - **Image 1**: Describes procedures such as sending bytes in significant order, illustrating decision-making in transmitting data. #### **Prozessbeschreibungen (Process Descriptions)** - **Image 1**: Describes the BNF (Backus-Naur Form) and the process for encoding ASCII characters and constructing network command strings. #### **Typen Bezeichnung (Type Designations)** - **Image 1**: Identifies types such as ALPHA, DIGIT, CRLF, and SP in the context of BNF specifications. #### **Trend and Interpretation** - **Trend**: Usage of formal specifications like BNF in defining network communication protocols. - **Interpretation**: Emphasizes the importance of standardized command formats to ensure interoperability and proper data exchange across network applications. #### **Tables** - **Image 1**: Contains a table within "Figure 3.2" for BNF specification, showing different command lines and rules used for username and password commands. In summary, **Image 1** is an educational and informative page focusing on ASCII characters and BNF specifications integral to computer networking. The diagram and corresponding text serve to elucidate necessary protocols and commands for effective network communication. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 34 Context: The first possibility was named `big-endian` in a note written by Cohen [Cohen1980] while the second was named `little-endian`. Vendors of CPUs that used `big-endian` in memory insisted on using `big-endian` encoding in networked applications while vendors of CPUs that used `little-endian` recommended the opposite. Several studies were written on the relative merits of each type of encoding, but the discussion became almost a religious issue (Cohen1980). Eventually, the Internet chose the `big-endian` encoding, i.e., multi-byte fields are always transmitted by sending the most significant byte first, RFC 791 refers to this encoding as the `network-byte order`. Most libraries¹ used to write networked applications contain functions to convert multi-byte fields from memory to the network byte order and vice versa. Besides 16 and 32 bit words, some applications need to exchange data structures containing bit fields of various lengths. For example, a message may be composed of a 16 bit field followed by eight, one bit flags, a 24 bits field and two 8 bits bytes. Internet protocol specifications will define such a message by using a representation such as the one below. In this representation, each line corresponds to 32 bits and the vertical lines are to delineate fields. The numbers above the lines indicate the bit positions in the 32-bits word, with the high order bit at position 0. ![Figure 3.3: Message format](#) The message mentioned above will be transmitted starting from the upper 32-bits word in network byte order. The first field is encoded in 16 bits. It is followed by eight one bit flags (A-H), a 24 bits field whose high order byte is shown in the first line and the two low order bytes appear in the second line followed by two new byte fields. This ASCII representation is frequently used when defining binary protocols. We will use it for all the binary protocols that are discussed in this book. We will discuss several examples of application-level protocols in this chapter. ### 3.2.1 The peer-to-peer model The peer-to-peer model emerged during the last ten years as another possible architecture for networked applications. In the traditional client-server model, hosts either act as servers or clients and a server serves a large number of clients. In the peer-to-peer model, all hosts act as both servers and clients and they play both roles. The peer-to-peer model has been used to develop various networked applications, ranging from Internet file sharing to Internet-wide filesystems. A detailed description of peer-to-peer applications may be found in [BYL2008]. Surveys of peer-to-peer protocols and applications may be found in [AS2004] and [LCP2005]. ### 3.3 The transport services Networked applications are built on top of the transport service. As explained in the previous chapter, there are two main types of transport services: - The connectionless or datagram service - The connection-oriented or byte-stream service The connectionless service allows applications to easily exchange messages or Service Data Units. On the Internet, this service is provided by the UDP protocol that will be explained in the next chapter. The connectionless transport service on the Internet is unreliable, but is able to detect transmission errors. This implies that an application will not receive an SDU that has been corrupted due to transmission errors. ¹ For example, the `recvfrom(2)` [man.7] function in the standard C library converts a 32-bit unsigned integer from the byte order used by the CPU to the network byte order (resp. from the network byte order to the CPU byte order). Similar functions exist in other programming languages. Image Analysis: ### Comprehensive Examination: Image Analysis #### 1. **Localization and Attribution** - **Image Placement**: There is one image located roughly in the middle of a single text-heavy page, identified as **Figure 3.3: Message format**. - **Image Number**: Image 1. #### 2. **Object Detection and Classification** - **Image 1**: The image is a diagram or chart that visually represents a message format for network protocols. It consists of a series of boxes and lines that convey bit positions. #### 3. **Scene and Activity Analysis** - **Image 1**: The image shows a schematic of how message transmission occurs at the bit level in network communication protocols. It is a technical illustration, not depicting any real-world scene or human activity. #### 4. **Text Analysis** - **Image 1 Text Detected**: - Title: "Figure 3.3: Message format" - Inside Image: Numbers and text indicating bit positions; "31 .... 24 23 .... 16 15 .... 8 7 .... 0." Each box under these numbers denotes 8 bits. - Text surrounding the image describes endianness and message structure in network protocols. - **Text Significance**: The text is part of an educational or instructional book on computer networking, specifically discussing byte order (big-endian vs. little-endian) and the construction of messages in network protocols. #### 5. **Diagram and Chart Analysis** - **Axes and Scalars**: The horizontal axis represents bit positions in a 32-bit word, marked from "31" to "0." - **Key Insighs**: The diagram provides a visual representation of how bits are organized in network messages, which is crucial for understanding data transmission integrity and byte order (endianness). #### 7. **Anomaly Detection** - **No Anomalies Detected**: The diagram appears to be correctly depicting the intended message format without errors or discrepancies. #### 8. **Color Analysis** - **Image 1 Color Composition**: The image is in grayscale. Dominant colors are black text and lines on a white background. This typical technical document styling ensures clarity and focuses on the content rather than aesthetics. #### 9. **Perspective and Composition** - **Perspective**: The image uses a straight-on, two-dimensional perspective to clearly present the information. - **Composition**: The bits are linearly arranged from left to right (31 to 0), aiding in understanding the sequence and byte order. #### 10. **Contextual Significance** - The image is part of an educational text on computer networking principles and is likely used to support the textual explanation of byte order and message formats. It serves as an illustrative aid to clarify the textual content. #### 12. **Graph and Trend Analysis** - **Data Points**: The significant data points are the bit positions from 31 to 0. Each section (each 8-bit segment) is crucial in constructing the overall 32-bit message structure. - **Trends**: Not applicable as this is a static representation rather than a dynamic trend chart. #### 13. **Graph Numbers** - Data Points: For a 32-bit message, the data points are segmented as follows: - 31 to 24 (First 8 bits) - 23 to 16 (Second 8 bits) - 15 to 8 (Third 8 bits) - 7 to 0 (Fourth 8 bits) #### **Additional Aspects:** - **Ablaufprozesse (Process Flows)**: The diagram does not depict process flows, focusing instead on bit-level message formats. - **Prozessbeschreibungen (Process Descriptions)**: This section of the text provides a high-level description of message encoding in network protocols. - **Typen Bezeichnung (Type Designations)**: Various types mentioned in the text include big-endian and little-endian encoding methods. ### Summary This page is from a textbook on computer networking, providing a detailed explanation of how messages are encoded at the bit level. The diagram (Figure 3.3) and the accompanying text explain the concept of big-endian and little-endian formats and the structure of a 32-bit message in network communication protocols, enhancing the reader's understanding of application-level protocol operation. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 35 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 The connectionless transport service allows networked applications to exchange messages. Several networked applications may be running at the same time on a single host. Each of these applications must be able to exchange SDUs with remote applications. To enable these exchanges of SDUs, each networked application running on a host is identified by the following information: - **The host** on which the application is running - **The port number** on which the application listens for SDUs On the Internet, the port number is an integer and the host is identified by its network address. As we will see in chapter The network layer there are two types of Internet Addresses: - **IP version 4** addresses that are 32 bits wide - **IP version 6** addresses that are 128 bits wide IPv4 addresses are usually represented by using a dotted decimal representation where each decimal number corresponds to one byte of the address, e.g., `203.0.113.16`. IPv6 addresses are usually represented as a set of hexadecimal numbers separated by colons, e.g., `2001:db8:3002:1a2f:ffee:6465:650`. Today, most Internet hosts have one IPv4 address. A small fraction of them also have an IPv6 address. In the future, we can expect that more and more hosts will have IPv6 addresses and that some of them will not have an IPv4 address anymore. A host that only has an IPv4 address cannot communicate with a host having only an IPv6 address. The figure below illustrates two that are using the datagram service provided by UDP on hosts that are using IPv4 addresses. ![Datagram service](path/to/image) **Figure 3.4:** The connectionless or datagram service The second transport service is the connection-oriented service. On the Internet, this service is often called the **byte-stream service** as it creates a reliable byte stream between two applications that are linked by a transport connection. Like the datagram service, the networked applications that use the byte-stream service are identified by the host on which they run and a port number. These hosts can be identified by an IPv4 address, an IPv6 address or a name. The figure below illustrates two applications that are using the byte-stream service provided by the TCP protocol on IPv6 hosts. The byte stream service provided by TCP is reliable and bidirectional. ## 3.4 Application-level protocols Many protocols have been defined for networked applications. In this section, we describe some of the important applications that are used on the Internet. We first explain the Domain Name System (DNS) that enables hosts to be identified by human-friendly names instead of the IPv4 or IPv6 addresses that are used by the network. Then, we describe the operation of electronic mail, one of the first killer applications on the global Internet, and the protocols used on the world wide web. ### 3.4.1 The Domain Name System In the early days of the Internet, there were only a few number of hosts (mainly minicomputers) connected to the network. The most popular applications were remote login and file transfer. By 1983, there were already five Image Analysis: ### Image Analysis #### 1. **Localization and Attribution** - The page contains one diagram located centrally in the middle of the page. - **Image Number**: Image 1 #### 2. **Object Detection and Classification** - **Image 1:** - **Objects Detected:** - Two application instances labeled "Applic. 1" and "Applic. 2". - Two rectangular boxes representing these applications. - Lines and arrows depicting the flow between these applications. - Text descriptions providing IP addresses, protocols, and port numbers. - **Key Features:** - Applications connected via a datagram service. - Identification labels providing specific technical details. #### 3. **Scene and Activity Analysis** - **Image 1:** - **Entire Scene:** - The diagram illustrates a network scenario where two applications communicate via datagram service using UDP (User Datagram Protocol) on the Internet. - **Activities Taking Place:** - Exchange of datagram packets between two networked applications. - **Main Actors and Actions:** - "Applic. 1" (IP address 130.104.32.107, Protocol UDP, Port 1234) sending/receiving data to/from "Applic. 2" (IP address 139.165.16.12, Protocol UDP, Port 53). #### 4. **Text Analysis** - **Image 1:** - **Detected Text:** - "Figure 3.4: The connectionless or datagram service" - In the diagram: "Identification," "IP address : 130.104.32.107," "Protocol : UDP," "Port : 1234," "IP address : 139.165.16.12," "Port : 53" - **Content Significance:** - The text provides technical details about the networking protocol and specific IP addresses and port numbers used by the applications in the datagram service. #### 5. **Diagram and Chart Analysis** - **Image 1:** - **Data and Trends Presented:** - The diagram shows a basic network interaction using datagram service. - **Axes, Scales, and Legends:** - No specific axes or scales as it is a conceptual diagram. - **Key Insights:** - Highlights the use of UDP protocol for connectionless communication between applications identified by specific IP addresses and port numbers. #### 8. **Color Analysis** - **Image 1:** - **Color Composition:** - Dominant colors are black and white with blue accents. - Blue is used to highlight key points and connections within the network diagram. - **Impact on Perception:** - The use of blue for connections draws attention to the flow of data between applications. #### 9. **Perspective and Composition** - **Image 1:** - **Perspective:** - Standard, straightforward view often used in technical documentation. - **Composition:** - The diagram is centered with text labels providing necessary details below and within the diagram. - Balanced arrangement of application instances with connecting arrows. #### 10. **Contextual Significance** - **Image 1:** - **Overall Document Context:** - The image is part of an educational text on computer networking principles, particularly focused on protocols and practice. - **Contribution to Overall Message/Theme:** - It visually explains the concept of connectionless service using a datagram service, aiding in the understanding of network communication using UDP. #### 13. **Graph Numbers** - **Figure 3.4:** - Application 1: IP address 130.104.32.107, Protocol: UDP, Port: 1234 - Application 2: IP address 139.165.16.12, Protocol: UDP, Port: 53 #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 36 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## 3.2 The Application Layer ### Figure 3.5: The connection-oriented or byte-stream service #### Identification - **IP address**: 2001:6a8:3080:2:217:2ff:fed6:65c0 - **Protocol**: TCP - **Port**: 1234 #### Identification - **IP address**: 2001:4860:a005::68 - **Protocol**: TCP - **Port**: 53 Hundreds of hosts are attached to the Internet. Each of these hosts is identified by a unique IPv4 address. Forcing human users to remember the IPv4 addresses of the remote hosts that they want to use was not user-friendly. Human users prefer to remember names and use them when needed. Using names as aliases for addresses is a common technique in Computer Science. It simplifies the development of applications and allows the developer to ignore the low-level details. For example, by using a programming language instead of writing machine code, a developer can write software without knowing whether the variables that it uses are stored in memory or inside registers. Because names are at a higher level than addresses, they allow (both in the example of programming above, and on the Internet) to treat addresses as mere technical identifiers, which can change at will. Only the names are stable. On today's Internet, where switching to another ISP means changing your IP addresses, the user-friendliness of domain names is less important (they are not often typed by users) but their stability remains a very important, may be their most important property. The first solution that allowed applications to use names was the `hosts.txt` file. This file is similar to the symbol table found in compiled code. It contains the mapping between the name of each Internet host and its associated IP address. ¹ It was maintained by SRI International that coordinated the Network Information Center (NIC). When a new host was connected to the network, the system administrator had to register its name and IP address at the NIC. The NIC updated the `hosts.txt` file on its server. All Internet hosts regularly retrieved the updated `hosts.txt` file from the server maintained by SRI. This file was stored at a well-known location on the Internet host (see RFC 952) and networked applications could use it to find the IP address corresponding to a name. A `hosts.txt` file can be used when there are up to a few hundred hosts on the network. However, it is clearly not suitable for a network containing thousands or millions of hosts. A key issue in a large network is to define a suitable naming scheme. The ARPANET initially used a flat naming space, i.e., each host was assigned a unique name. To limit collisions between names, these names usually contained the name of the institution and a suffix to identify the host inside the institution (a kind of poor man's hierarchical naming scheme). On the ARPANET few institutions had several hosts connected to the network. However, the limitations of a flat naming scheme became clear before the end of the ARPANET and RFC 819 proposed a hierarchical naming scheme. While RFC 819 discussed the possibility of organizing the names in a directed graph, the Internet opted eventually for a tree structure capable of containing all names. In this tree, top-level domains are those that are directly attached to the root. The first top-level domain was `.arpa`. This top-level name was initially added as a suffix to the names of the hosts attached to the ARPANET and listed in the `hosts.txt` file. In 1984, the .gov, .edu, .com, .mil, and .org generic top-level domains were added and RFC 1032 proposed the utilization of the two letter ISO-3166 country codes as top-level names. Since ² The host.txt file is not maintained anymore. A historical snapshot retrieved on April 15th, 1984 is available from [http://ipinfo.io/attct/hosts.txt](http://ipinfo.io/attct/hosts.txt). ³ See [http://www.domain.com/misc/internet.txt](http://www.domain.com/misc/internet.txt) for a time of DNS related developments. Image Analysis: ### Localization and Attribution: - **Image Number:** Image 1 - **Location:** The image is positioned in the upper section of the page, centered horizontally. ### Object Detection and Classification: - **Objects Identified:** - Two labeled nodes with the identifier "Applic. 1" and "Applic. 2". - A connecting line labeled "Byte-stream service". - Two sets of identification details containing IP address, protocol, and port information. - **Classification:** - Nodes ("Applic. 1" and "Applic. 2") are applications. - Connecting line represents a byte-stream service. - Identification details include network details like IP addresses and protocol information. ### Scene and Activity Analysis: - **Scene Description:** - The image depicts a schematic diagram explaining the concept of a connection-oriented or byte-stream service between two applications ("Applic. 1" and "Applic. 2"). - **Main Actors and Actions:** - The main actors are the applications labeled as Applic. 1 and Applic. 2. - The activity involves establishing a byte-stream communication service using specific network identification parameters. ### Text Analysis: - **Extracted Text:** - Labels: "Applic. 1", "Applic. 2", "Byte-stream service" - Identification details: ``` Identification: IP address : 2001:6a8:3080:2:217:f2ff:fed6:65c0 Protocol : TCP Port : 1234 Identification: IP address : 2001:4860:a005::68 Protocol : TCP Port : 53 ``` - **Significance:** - The text provides important network parameters such as IP addresses, protocol type (TCP), and port numbers, highlighting the details involved in a network communication setup. ### Diagram and Chart Analysis: - **Diagram Analysis:** - The diagram is a network schematic illustrating the byte-stream service between two application endpoints. - **Key Insights:** - The connections use different IP addresses and ports, indicating distinct communication channels. ### Anomaly Detection: - **No noticeable anomalies detected:** The diagram appears standard and clear, with no unusual elements impacting the understanding of the content. ### Color Analysis: - **Dominant Colors:** - Black text and lines on a white background. - **Impact on Perception:** - The black and white color scheme provides high contrast, ensuring clarity and readability. ### Perspective and Composition: - **Perspective:** - The diagram is a straightforward 2D representation, viewed from a standard straight-on perspective. - **Composition:** - The elements are symmetrically arranged, with two application nodes on the left and right, connected by a label indicating the type of service. ### Contextual Significance: - **Role in Document:** - The diagram complements the surrounding text, offering a visual representation of the described networking concepts. - **Contribution to Overall Message:** - Provides a clear example of how byte-stream services work in network communication, reinforcing the theoretical explanations provided in the text. ### Metadata Analysis: - **No metadata available:** Unable to analyze due to lack of metadata from the provided content. ### Graph and Trend Analysis: - **N/A** ### Graph Numbers: - **N/A** ### Ablaufprozesse (Process Flows): - **N/A** ### Prozessbeschreibungen (Process Descriptions): - **N/A** ### Typen Bezeichnung (Type Designations): - **Types Identified:** - Application labels: "Applic. 1" and "Applic. 2" - Connection type: Byte-stream service ### Trend and Interpretation: - **N/A** ### Tables: - **N/A** #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 37 Context: ISO-3166 defines a two-letter code for each country recognized by the United Nations; this allowed all countries to automatically have a top-level domain. These domains include .be for Belgium, .fr for France, .ie for Ireland, or .tv for Tuvalu, a group of small islands in the Pacific and .tm for Turkmenistan. Today, the set of top-level domain names is managed by the Internet Corporation for Assigned Names and Numbers (ICANN). Recently, ICANN added a dozen of generic top-level domains that are not related to a country and the cat top-level domain has been registered for the Catalan language. There are ongoing discussions within ICANN to increase the number of top-level domains. ### Figure 3.6: The tree of domain names RFC 1035 recommended the following BNF for fully qualified domain names, to allow host names with a syntax which works with all applications (the domain names themselves have a much richer syntax). ### Figure 3.7: BNF of the fully qualified host names This grammar specifies that a host name is an ordered list of labels separated by the dot (.) character. Each label can contain letters, numbers and the hyphen character (-). Fully qualified domain names are read from left to right. The first label is a hostname or a domain name followed by the hierarchy of domains and ending with the root implicitly at the right. The top-level domain name must be one of the registry TLDs. For example, in the above figure, `www.whitehouse.gov` corresponds to a host named `www` inside the `whitehouse` domain that belongs to the top-level domain. `info.ic.dal.ca` corresponds to the `info` domain inside the `ic` sub-domain of the top-level domain. This hierarchical naming scheme is a key component of the Domain Name System (DNS). The DNS is a distributed database that contains mappings between fully qualified domain names and IP addresses. The DNS uses the client-server model. The clients are hosts that need to retrieve the mapping for a given name. Each nameserver stores part of the distributed database and answers the queries set by clients. There is at least one nameserver that is responsible for each domain. In the figure below, domains are represented by circles and there are three hosts inside domain (h1, h2 and h3) and three hosts inside domain d.sub1.dom. As shown in the figure below, a sub-domain may contain both host names and sub-domains. - A nameserver that is responsible for domain dom can directly answer the following queries: - The IP address of any host residing directly inside domain dom (e.g., h2 in dom in the figure above). - The nameserver(s) that are responsible for any direct sub-domain of domain dom (i.e., sub1.dom and sub2.dom in the figure above, but not .dom). **Note:** This specification evolved later to support domain names written by using other character sets than as-ASCII RFC 3596. This extension is important to support languages other than English, but a detailed discussion is outside the scope of this document. The official list of top-level domain names is maintained by [IANA](https://www.iana.org/assignments/root-zone-status/root-zone-status-x.html). Additional information about these domains may be found at [Wikipedia](https://en.wikipedia.org/wiki/List_of_Internet_top-level_domains). ### 3.4 Application-level protocols 33 Image Analysis: ### Comprehensive Examination of the Attached Visual Content #### 1. Localization and Attribution: - **Image 1 (Top to bottom):** Figure 3.6: The tree of domain names - **Image 2 (Below Image 1):** Figure 3.7: BNF of the fully qualified host names #### 2. Object Detection and Classification: - **Image 1 (Figure 3.6):** - **Objects:** Circles labeled with different domain names and lines connecting them. - **Categories:** Domain types (e.g., gov, com, edu, int, ca). - **Image 2 (Figure 3.7):** - **Objects:** Text explaining the BNF (Backus-Naur Form) for fully qualified host names. - **Categories:** Text and notation (e.g., letters, dots, hyphens). #### 3. Scene and Activity Analysis: - **Image 1 (Figure 3.6):** - **Scene:** Hierarchical tree diagram of domain names. - **Activity:** Visualization of the relationships and hierarchy among various domain names. - **Image 2 (Figure 3.7):** - **Scene:** Textual representation of the syntax rules for fully qualified host names. - **Activity:** Explanation and demonstration of how domain names are structured using BNF notation. #### 4. Text Analysis: - **Image 1 (Figure 3.6):** - **Text Detected:** - Labels such as "root", "edu", "gov", "com", "org", "mit", "yahoo", etc. - **Significance:** - Demonstrates the hierarchical structure of domain names starting from the root. - **Image 2 (Figure 3.7):** - **Text Detected:** - Full text explaining how the labels in a host name are ordered and defined using BNF. - **Significance:** - Provides a formal specification for the syntax of fully qualified domain names, critical for understanding domain name resolution in computer networking. #### 5. Diagram and Chart Analysis: - **Image 1 (Figure 3.6):** - **Diagram:** - A hierarchical tree structure showcasing the parent-child relationship between top-level domains (TLDs) and lower levels. - **Key Insights:** - Illustrates the systematic organization of domain names from the root to specific domains such as "yahoo.com" and "mit.edu". - **Image 2 (Figure 3.7):** - **Chart:** - BNF syntax rules displayed in a textual flow. - **Key Insights:** - Details the grammar for creating valid, fully qualified domain names. #### 8. Color Analysis: - **Image 1 (Figure 3.6):** - **Color Composition:** - Mostly black-and-white for text with some blue and purple annotations. - **Impact:** - The colors help differentiate between different domains and add emphasis to important connections. - **Image 2 (Figure 3.7):** - **Color Composition:** - Predominantly black-and-white text. - **Impact:** - Standard text presentation designed for readability and clarity. #### 9. Perspective and Composition: - **Image 1 (Figure 3.6):** - **Perspective:** - Frontal view of a hierarchical tree. - **Composition:** - Sequentially arranged from top (root) to bottom (specific domains), demonstrating domain hierarchy clearly. - **Image 2 (Figure 3.7):** - **Perspective:** - Frontal view of a text-based explanation. - **Composition:** - Text arranged in a logical flow with bullet points and numbered items to aid in understanding the syntax rules. #### 10. Contextual Significance: - **Context in Document (Overall):** - The images are part of a chapter on "Computer Networking: Principles, Protocols and Practice", specifically discussing domain names in the context of internet protocols. - **Contribution:** - Image 1 (Figure 3.6) provides a visual aid to understand domain hierarchy, essential for grasping how domain name system (DNS) works. - Image 2 (Figure 3.7) delivers the foundational rules for domain naming, important for technical accuracy when implementing or studying DNS systems. #### 11. Metadata Analysis: - No metadata is visible in the images provided. Assuming standard document metadata, such as author, creation date, and modification details, this can help understand the versioning and updates pertinent to networking protocols. ### Conclusion The attached images provide detailed visual and textual explanations of domain names and their hierarchical structure. These visual aids are instrumental in understanding the organization and syntax of domain names, crucial for DNS and networking principles. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 38 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ![Figure 3.8: A simple tree of domain names](image-link) To retrieve the mapping for host `h2.dom`, a client sends its query to the name server that is responsible for domain `.dom`. The name server directly answers the query. To retrieve a mapping for `h3.a.sdom.dom`, a DNS client first sends a query to the name server that is responsible for the `.dom` domain. This nameserver returns the nameserver that is responsible for the `sdom.dom` domain. This nameserver can now be contacted to obtain the nameserver that is responsible for the `a.sdom.dom` domain. This nameserver can be contacted to retrieve the mapping for the `h2.a.sdom.dom` name. Thanks to this organization of the nameservers, it is possible for a DNS client to obtain the mapping of any host inside the domain or any of its subdomains. To ensure that any DNS client will be able to resolve any fully qualified domain name, there are special nameservers that are responsible for the root of the domain name hierarchy. These nameservers are called **root nameserver**. There are currently about a dozen root nameservers. Each root nameserver maintains the list of all the nameservers that are responsible for each of the top-level domain names and their IP addresses. [^1] All root nameservers are synchronized and provide the same answers. By querying any of the root nameservers, a DNS client can obtain the nameserver that is responsible for any top-level domain name. From this nameserver, it is possible to resolve any domain name. To be able to contact the root nameservers, each DNS client must know their IP addresses. This implies that DNS clients must maintain an up-to-date list of the IP addresses of the root nameservers. Without this list, it is impossible to contact the root nameservers. Forcing all Internet hosts to maintain the most recent version of this list would be difficult from an operational point of view. To solve this problem, the designers of the DNS introduced a special type of DNS server: the **DNS resolver**. A resolver is a server that provides the names resolution service for a set of clients. A network usually contains a few resolvers; these resolvers are configured to send all DNS queries via one of its local resolvers. These queries are called recursive queries as the resolver must resolve through the hierarchy of nameservers to obtain the answer. DNS resolvers have several advantages over letting each Internet host query directly nameservers. Firstly, regular Internet hosts do not need to maintain up-to-date lists of the IP addresses of the root servers. Secondly, regular Internet hosts do not need to send queries to nameservers all over the Internet. Furthermore, as a DNS resolver serves a large number of hosts, it can cache the received answers. This allows the resolver to quickly return answers for popular DNS queries and reduces the load on all DNS servers [^2]. The last component of the Domain Name System is the DNS protocol. The DNS protocol runs above both the datagram service and the bytesream service. In practice, the datagram service is used when short queries and responses are exchanged, and the bytesream service is used when longer responses are expected. In this section, we will only discuss the utilization of the DNS protocol above the datagram service. This is the most frequent utilization of the DNS. DNS messages are composed of five parts that are named sections in RFC 1035. The first three sections are mandatory and the last two sections are optional. The first section of a DNS message is its **Header**. It contains: 1. Identification (16 bits) 2. Flags (16 bits) 3. Number of questions (16 bits) 4. Number of answer resource records (16 bits) 5. Number of authority resource records (16 bits) 6. Number of additional resource records (16 bits) [^1]: There are currently 13 root servers. In practice, some of these root servers are themselves implemented as a set of distinct physical servers. [http://www.root-servers.org](http://www.root-servers.org) [^2]: Until February 2008, the root DNS servers had only IPv4 addresses. [RFC 4466](https://www.rfc-editor.org/rfc/rfc4466.txt) addresses were added to the root DNS servers slowly to avoid creating problems as discussed in [http://www.icann.org/en/committees/security/tac/03apr08.htm](http://www.icann.org/en/committees/security/tac/03apr08.htm), several DNS root servers are still not reachable using IPv6. Image Analysis: ### Image Analysis Report #### **Localization and Attribution** - **Image 1**: The visual content consists of a single image in the document. This image is situated in the center of the page and is titled "Figure 3.8: A simple tree of domain names". #### **Object Detection and Classification** - **Image 1**: - **Objects**: The image includes a diagram of a hierarchical tree structure. - **Classification**: The tree diagram displays nodes and connections, representing domain names in a hierarchical manner typical in network topology illustrations. #### **Scene and Activity Analysis** - **Image 1**: - **Scene Description**: The diagram depicts a hierarchy of domain names. The top-level domain is “dom”, followed by second-level domains (sdom1, sdom2), and third-level domains (h1, h2, h3 for sdom1, and h2, h3 for sdom2). A, B, Z are sub-domains under specific second-level domains (sdoma). - **Activities**: This setup represents the process of mapping and resolving domain names in a DNS system. #### **Text Analysis** - **Extracted Text**: The figure includes labels like "dom", "sdom1", "sdom2", "h1", "h2", "h3", "a", "b", and "z". The accompanying text provides detailed descriptions of the DNS query process and functionalities of DNS resolvers. - **Significance**: The extracted text helps explain the hierarchical nature of domain name resolution and the roles of different servers within the DNS architecture. #### **Diagram and Chart Analysis** - **Figure Analysis**: - **Data and Trends**: The tree structure shows a clear hierarchical organization. Each level represents a different level in the DNS hierarchy. - **Axes, Scales, and Legends**: There are no axes, scales, or legends in this figure. The figure serves as a simple visual representation rather than a graph. #### **Contextual Significance** - **Overall Document Context**: The image contributes to the chapter’s explanation of the Domain Name System (DNS). By illustrating the hierarchical structure and the query process, the image aids in visualizing the text's concepts. - **Message Contribution**: It reinforces the understanding of how DNS servers are organized and how domain name queries are resolved across different levels. #### **Color Analysis** - **Dominant Colors**: The image is composed of black and white, typical for technical diagrams aimed at clarity and simplicity. - **Impact on Perception**: The monochromatic nature ensures focus remains on the structure and labels without any color distraction. #### **Perspective and Composition** - **Perspective**: The image is created from a straight-on perspective, focusing on clarity and comprehensibility. - **Composition**: The hierarchical tree structure is centered with clear labels, making the relationships between different domains easily discernible. #### **Prozessbeschreibungen (Process Descriptions)** - **Process of DNS Query**: The image and the accompanying text together describe the process of a DNS query, mapping domain names to IP addresses through a hierarchical tree. This facilitates understanding of how DNS queries traverse through different servers (root, top-level, second-level) to resolve to the specific IP address. #### **Typen Bezeichnung (Type Designations)** - **DNS Servers Types**: The text describes different types of DNS servers, including recursive DNS servers, DNS resolvers, root nameservers, and their roles in the DNS infrastructure. #### **Trend and Interpretation** - **Hierarchical Model**: The use of a tree model signifies the structured and hierarchical nature of domain name resolution. - **Scalability and Efficiency**: The text outlines how hierarchical organization aids in scalability and efficiency of DNS lookups. #### **Tables** - No tables were found within the image or the surrounding text. ### Conclusion: This single image, part of a larger chapter on DNS, effectively explains the hierarchical structure of domain names. The tree diagram aids in visual understanding, while the surrounding text provides detailed explanations of DNS query processes and server roles. This combination enhances the reader’s grasp of domain name resolution mechanics within computer networks. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 39 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 The header of DNS messages is composed of 12 bytes and its structure is shown in the figure below. ``` 1 1 1 1 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +---+---+---+---+---+---+---+---+---+---+---+---+ | ID | +---+---+---+---+---+---+---+---+---+---+---+---+ | QR | Opcode | AA | TC | RD | RA | Z | RCODE | +---+---+---+---+---+---+---+---+---+---+---+---+ | QDCOUNT | +---+---+---+---+---+---+---+---+---+---+---+---+ | ANCOUNT | +---+---+---+---+---+---+---+---+---+---+---+---+ | NSCOUNT | +---+---+---+---+---+---+---+---+---+---+---+---+ | ARCOUNT | +---+---+---+---+---+---+---+---+---+---+---+---+ Figure 3.9: DNS header ``` The **ID** (identifier) is a 16-bits random value chosen by the client. When a client sends a question to a DNS server, it remembers the question and its identifier. When a server returns an answer, it returns in the ID field the identifier chosen by the client. Thanks to this identifier, the client can match the received answer with the question that it sent. The **QR flag** is set to 0 in DNS queries and 1 in DNS answers. The **Opcode** is used to specify the type of query. For instance, a **standard query** is when a client sends a name and the server returns the corresponding data and an update request is when the client sends a name and new data and the server updates its database. The **AA** bit is set when the server that sent the response has authority for the domain name found in the question section. In the original DNS deployments, two types of servers were considered: **authoritative servers** and **non-authoritative servers**. The authoritative servers are managed by the system administrators responsible for a given domain. They always store the most recent information about a domain. Non-authoritative servers provide resolvers that store DNS information about external domains without being managed by the owners of a domain. They may thus provide answers that are out of date. From a security point of view, the authoritative bit is not an absolute indication about the validity of an answer. Securing the Domain Name System is a complex problem and was only addressed satisfactorily recently by the utilization of cryptographic signatures in the DNSSEC extensions to DNS described in RFC 403. However, these extensions are outside the scope of this chapter. The **RD** (recursion desired) bit is set by a client when it sends a query to a resolver. Such a query is said to be recursive because the resolver will recurse through the DNS hierarchy to retrieve an answer on behalf of the client. In the past, all resolvers were configured to perform recursive queries on behalf of any Internet host. However, this exposes the resolvers to several security risks. The simplest one is that the resolver could become overloaded by having too many recursive queries to process. As of this writing, most resolvers** only allow recursive queries from clients belonging to their company or network and discard all other recursive queries. The **A** bit indicates whether the server supports recursion. The **RCODE** is used to distinguish between different types of errors. See RFC 1035 for additional details. The last four fields indicate the size of the **Question**, **Answer**, **Authority** and **Additional** sections of the DNS message. **Note:** Some DNS resolvers allow only host to send queries. OpenDNS and GoogleDNS are examples of open resolvers. ## 3.4 Application-level protocols Image Analysis: ### Comprehensive Examination of Attached Visual Content #### 1. Localization and Attribution: - **Image 1**: The primary image located centrally on the page. #### 2. Object Detection and Classification: - **Image 1**: Contains a structured diagram of a DNS header. #### 3. Scene and Activity Analysis: - **Image 1**: Illustrates the structure of a DNS (Domain Name System) header and describes the purpose and significance of each section within the header. #### 4. Text Analysis: - **Text Above the Diagram**: - The text explains the purpose of each section of a DNS message: - **ID** (identifier): Chosen by the client and used to match responses to requests. - **QR, Opcode, AA, TC, RD, RA, Z, RCODE**: Various flags and codes for query/response type, authoritative answer flags, recursion, and error codes. - **QDCOUNT, ANCOUNT, NSCOUNT, ARCOUNT**: Counts for questions, answers, authority, and additional records. - **Text Below the Diagram**: - Provides detailed descriptions of each part of the DNS header: - **ID**: 16-bit random value chosen by the client. - **QR flag**: Differentiates between queries and responses. - **Opcode**: Specifies the type of query. - **AA flag**: Indicates an authoritative answer. - **TC flag**: Specifies if a message was truncated. - **RD flag**: Indicates if recursion was desired. - **RA flag**: Indicates if recursion is available. - **Z**: Reserved for future use. - **RCODE**: Indicates the status of the response. - **Counts (QDCOUNT, ANCOUNT, NSCOUNT, ARCOUNT)**: Provides the counts of associated sections in the DNS message. #### 5. Diagram and Chart Analysis: - **Figure 3.9: DNS Header**: - **Axes/Structure**: The diagram is arranged into a 12-byte structure with various fields. - **Key Insights**: - The layout illustrates the different segments and their usage within a DNS header message. - Important data segments include ID, control flags (QR, Opcode, etc.), and record counts. #### 12. Graph and Trend Analysis: - **Data Points**: - **ID**: A unique number for each DNS query. - **QR**: Differentiates query (0) from response (1). - **Opcode**: Specifies query type (usually 0 for standard query). - **AA**: Set by the responding server to indicate authority. - **TC**: Indicates if the message was truncated. - **RD**: Client-desired recursion. - **RA**: If recursion is available from the server. - **RCODE**: Indicates status/errors. - **QDCOUNT, ANCOUNT, NSCOUNT, ARCOUNT**: Counts indicating the specific number of each type of record. #### 13. Graph Numbers: - The diagram does not operate with numerical data in rows but provides a structured visual of a DNS message format. ### Additional Aspects: #### Ablaufprozesse (Process Flows): - The diagram itself illustrates a static structure, rather than a process flow, but the surrounding text details the processing steps of DNS queries and responses. #### Prozessbeschreibungen (Process Descriptions): - The text describes the lifecycle of a DNS query, including how the ID is matched, the role of each flag, and how the server takes appropriate actions based on these parameters. ### Conclusion: The provided image and the accompanying text from a computer networking book thoroughly describe the components and functions of the DNS header format. Each field in the header is explained in detail, providing valuable insights into how DNS queries and responses are structured and processed. This content is highly relevant for understanding the technical details of DNS in the context of computer networking protocols and practices. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 40 Context: The last four sections of the DNS message contain **Resource Records (RR)**. All RRs have the same top-level format shown in the figure below. ``` +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 | 1 | 2 | 3 | 4 | 5 | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | | | | | | | | | | | | | | | | | | | | | | | | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | NAME | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | TYPE | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | CLASS | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | TTL | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | RDLENGTH | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | RDATA | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ ``` **Figure 3.10: DNS Resource Records** In a **Resource Record (RR)**, the **Name** indicates the name of the node to which this resource record pertains. The two bytes **Type** field indicate the type of resource record. The **Class** field was used to support the utilization of the DNS in other environments than the Internet. The **TTL** field indicates the lifetime of the Resource Record in seconds. This field is set by the server that returns an answer and indicates for how long a client or a resolver can store the Resource Record inside its cache. A long TTL indicates a stable RR. Some companies use short TTL values for mobile hosts and also for popular servers. For example, a web hosting company that wants to spread the load over a pool of hundred servers can configure its nameservers to return different answers to different clients. If each answer has a small TTL, the clients will be forced to send DNS queries regularly. The nameserver will reply to these queries by supplying the address of the least loaded server. The **RDLENGTH** field is the length of the **RDATA** field that contains the information of the type specified in the **Type** field. Several types of DNS RR are used in practice. The **A** type is used to encode the IPv4 address that corresponds to the specified name. The **AAAA** type is used to encode the IPv6 address that corresponds to the specified name. The **NS** record contains the name of the DNS server that is responsible for a given domain. For example, a query for the **A** record associated to the `www.ietf.org` name returns the following answer. This answer contains several pieces of information. First, the name `www.ietf.org` is associated to IP address `64.170.98.32`. Second, the `ietf.org` domain is managed by six different nameservers. Three of those nameservers are reachable via IPv4 and IPv6. Two of them are not reachable via IPv4 and are only reachable via IPv6. A query for the AAAA record associated to `www.ietf.org` returns `2001:1050:112:2::20` and the associated authority and additional sections. **CNAME** (or canonical names) are used to define aliases. For example, `www.example.com` could be a CNAME for `pc12.example.com` that is the actual name of the server on which the web server for `www.example.com` runs. **Note**: Reverse DNS and in-addr.arpa --- ### Chapter 3. Part 2: The Application Layer 36 Image Analysis: ### 1. Localization and Attribution: - **Image 1**: - Located at the center of the page. - Labeled as "Figure 3.10: DNS Resource Records" below the image. ### 2. Object Detection and Classification: - **Image 1**: - Objects identified: A diagram/graph. - Category: Technical diagram related to computer networking. ### 3. Scene and Activity Analysis: - **Image 1**: - The scene depicts a detailed example of DNS Resource Records structure. - The diagram highlights various fields and their respective bit length within a DNS Resource Record. ### 4. Text Analysis: - **Image 1**: - Detected Text: - "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" - ... - "NAME" - ... - "TYPE" - ... - "CLASS" - ... - "TTL" - ... - "RDLENGTH" - ... - "RDATA" - ... - Explanation of terms and fields in the main text below the diagram. - Significance: - The text provides a detailed breakdown of the DNS Resource Record fields and their functional significance. Terms such as NAME, TYPE, CLASS, TTL, RDLENGTH, and RDATA are explained, indicating their role in DNS lookups and records. ### 6. Product Analysis: - **Image 1**: - Not applicable as the image does not depict any products. ### 7. Anomaly Detection: - **Image 1**: - No anomalies detected. The elements within the image are standard components of a DNS Resource Record diagram. ### 8. Color Analysis: - **Image 1**: - The image is primarily black and white. - Dominant colors: Black text on a white background. - Impact: Provides clear, contrastive detail to ensure that technical elements are easily readable. ### 9. Perspective and Composition: - **Image 1**: - The diagram appears in a straightforward, linear perspective. - Composition: Centralized and hierarchical, with sections delineated for clarity. The diagram follows a top-to-bottom flow, making it easy to read from the header to the detailed fields. ### 10. Contextual Significance: - **Image 1**: - The image contributes significantly to the educational purpose of the document, providing a clear visual aid to understand the DNS Resource Record structure. It complements the textual explanation on DNS Resource Records. ### 11. Metadata Analysis: - **Image 1**: - Metadata not available for analysis from the provided content. ### 13. Graph Numbers: - **Image 1**: - The diagram does not contain a traditional graph with data points but rather displays a structure with bit positions labeled. ### Additional Aspects: - **Ablaufprozesse (Process Flows)**: - The image describes the sequential structure of DNS Resource Records, implying steps followed during DNS lookup processes. - **Prozessbeschreibungen (Process Descriptions)**: - The text below the image details the function of each element, describing the DNS resolution process and record types. - **Typen Bezeichnung (Type Designations)**: - Specifies various types of DNS resource records such as A, AAAA, NS, and CNAME, and their relevance. Overall, the image serves as an instructional graphic, aiding in the understanding of DNS Resource Records within the broader context of computer networking education. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 41 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ![Figure 3.11: Query for the A record of www.ietf.org](Figure_3.11_Query_for_the_A_record_of_www.ietf.org) The DNS is mainly used to find the IP address that corresponds to a given name. However, it is sometimes useful to obtain the name that corresponds to an IP address. This is done by using the PTR (pointer) RR. The RData part of a PTR RR contains the name while the Name part of the RR contains the IP address encoded in the uint384r format. IPv4 addresses are encoded in the uint384r by reversing the four digits that compose the dotted decimal representation of the address. For example, consider IPv4 address 192.0.2.1. The hostname associated to this address can be found by requesting the PTR RR that corresponds to 11.2.0.192.in-addr.arpa. A similar solution is used to support IPv6 addresses, see RFC 3596. An important point to note regarding the Domain Name System is its extensibility. Thanks to the Type and RDLnq fields, the format of the Resource Records can easily be extended. Furthermore, a DNS implementation that receives a new Resource Record that it does not understand can ignore the record while still being able to process the other parts of the message. This allows, for example, a DNS server that only supports IPv4 to ignore the IPv6 addresses listed in the DNS reply for www.ietf.org while still being able to correctly parse the Resource Records that it understands. This extensibility allowed the Domain Name System to evolve over the years while still preserving the backward compatibility with already deployed DNS implementations. ## 3.4.2 Electronic Mail Electronic mail, or email, is a very popular application in computer networks such as the Internet. Email appeared in the early 1970s and allows users to exchange text-based messages. Initially, it was mainly used to exchange short messages, but over the years its usage has grown. It is now not only used to exchange small, but also long messages that can be composed of several parts as we will see later. Before looking at the email system in detail, let us consider a simple scenario illustrated in the figure below, where Alice sends an email to Bob. Alice prepares her email by using an email client and sends it to her email server. Alice’s email server extracts Bob’s address from the email and delivers the message to Bob’s server. Bob retrieves Alice’s message on his server and reads it by using his favorite email client or through his webmail interface. The email system that we consider in this book is composed of four components: - A message format that defines how valid email messages are encoded - Protocols that allow hosts and servers to exchange email messages - Client software that allows users to easily create and read email messages - Software that allows servers to efficiently exchange email messages ## 3.4. Application-level Protocols 37 Image Analysis: ### Analysis of Attached Visual Content #### 1. **Localization and Attribution:** - **Image(s) Identified:** - **Image 1:** Figure 3.11 titled "Query for the A record of www.ietf.org" located mid-page. #### 2. **Object Detection and Classification:** - **Image 1:** - **Objects Detected:** - Text commands and responses from a DNS query. - The figure caption, numbering, and legend beneath the image. - **Categories:** - Text, Computer/Network Commands. #### 4. **Text Analysis:** - **Main Text:** - Describes how the Domain Name System (DNS) is used to link IP addresses with domain names. - Explains the use of PTR (pointer) records and how they work to reverse-lookup an IP address into a domain name. - IPv4 addresses format explanations and example, detailing the process of encoding and reversing dotted decimal representation. - Details on the extensibility of the Domain Name System via Type and RDATA fields. - **Section Title:** - "3.4.2 Electronic mail" - Marks the beginning of a subsection focused on electronic mail within computer networking. - **Bullet Points:** - Describes the four components of an email system: message format, protocols, client software, and server software. #### 8. **Color Analysis:** - **Color Composition:** - Dominantly black and white text with grayscale shades for different headings. - The visual elements follow a traditional academic/documentary style, focusing on readability and clarity. #### 9. **Perspective and Composition:** - **Perspective:** - Straight-on, standard document perspective appropriate for academic and technical texts. - **Composition:** - Divided into two main parts: a block of text above and below the centered figure (Image 1). - Figure 3.11 centrally located and captioned, ensuring clear association with surrounding explanatory text. #### 10. **Contextual Significance:** - The image and accompanying text serve to illustrate and explain technical concepts related to DNS queries and electronic mail as part of a broader discussion on application-level protocols in computer networking. - The visual content aids in conceptualizing abstract networking operations, making the technical information more comprehensible. ### Summary: The page analyzed belongs to a networking textbook or guide, focusing on DNS operations and electronic mail within the domain of computer networking. The figure (Image 1) illustrates a practical DNS query example, enhancing the reader's understanding of the written explanation. The text delves into the technical specifics and standards relevant to DNS and email systems, forming part of an educational resource for students or professionals in the field of computer networking. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 42 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ![Figure 3.12: Simplified architecture of the Internet email](image_link_here) We will first discuss the format of email messages followed by the protocols that are used on today’s Internet to exchange and retrieve emails. Other email systems have been developed in the past [Bush1993][Geunllod1990][GC2000], but today most email solutions have migrated to the Internet email. Information about the software that is used to compose and deliver emails may be found on Wikipedia among others, for both email clients and email servers. More detailed information about the full Internet Mail Architecture may be found in RFC 5598. ## Email Messages Email messages, like postal mail, are composed of two parts: - **A header** that plays the same role as the letterhead in regular mail. It contains metadata about the message. - **The body** that contains the message itself. Email messages are entirely composed of lines of ASCII characters. Each line can contain up to 998 characters and is terminated by the CR and LF control characters RFC 5322. The lines that compose the header appear before the message body. An empty line, containing only the CR and LF characters, marks the end of the header. This is illustrated in the figure below. ![Figure 3.13: The structure of email messages](image_link_here) The email header contains several lines that all begin with a keyword followed by a colon and additional information. The format of email messages and the different types of header lines are defined in RFC 5322. Two of these header lines are mandatory and must appear in all email messages: - **The sender address.** This header line starts with `From:`. This contains the (optional) name of the sender followed by its email address between `<` and `>`. Email addresses are always composed of a username followed by the `@` sign and a domain name. - **The date.** This header line starts with `Date:`. RFC 5322 precisely defines the format used to encode a date. Other header lines appear in most email messages. The `Subject:` header line allows the sender to indicate the topic discussed in the email. Three types of header lines can be used to specify the recipients of a message: - **The `To:` header line** contains the email addresses of the primary recipients of the message. Several addresses can be separated by using commas. - **The `cc:` header line** is used by the sender to provide a list of email addresses that must receive a carbon copy of the message. Several addresses can be listed in this header line, separated by commas. All recipients of the email message receive the `To:` and `cc:` header lines. It could be surprising that the `To:` is not mandatory inside an email message. While most email messages will contain this header line an email that does not contain a `To:` header line and that relies on the `cc:` to specify the recipient is valid as well. Image Analysis: ### Analysis of Attached Visual Content #### 1. Localization and Attribution: - **Image 1**: Located near the top, it is labeled as "Figure 3.12: Simplified architecture of the Internet email." - **Image 2**: Located below the first image, it is labeled as "Figure 3.13: The structure of email messages." #### 2. Object Detection and Classification: - **Image 1**: - Objects: Diagrams of email servers and clients. - Key Features: This image shows a flow of data between different email entities including "alice's net", "alice's email user", "email server", and "bob's email user." - **Image 2**: - Objects: Sample email structure with headers and body. - Key Features: This image lists and visually presents an email header and body format along with some sample text and key points. #### 3. Scene and Activity Analysis: - **Image 1**: - Scene: It illustrates a simplified architecture of the Internet email. - Activities: Depicts the process of email exchange between different email servers and clients. - **Image 2**: - Scene: It provides a breakdown of the structure of email messages. - Activities: Shows how an email is structured with headers and the body, and details the types of information included in each part. #### 4. Text Analysis: - **Image 2**: - Detected Text: The image includes a diagram explaining: - "Header" - "Body" - "From" - "To" - "Cc" - "Date" - "Subject" - Analysis: This text helps understand the specific components and format of an email message, in line with RFC 5322. #### 9. Perspective and Composition: - **Image 1**: - Perspective: The diagram is presented from a front view, giving an overview of email server-client architecture. - Composition: Elements are arranged to show a flow from "alice's net" to "bob's net", indicating the pathway of email transfer. - **Image 2**: - Perspective: Top-down view of email message structure. - Composition: The elements (headers and body) are organized in a linear format to show the hierarchical structure of an email. #### 10. Contextual Significance: - **Image 1**: This image provides a visual explanation of the email communication process, which is crucial for understanding how Internet emails work. - **Image 2**: This image elaborates on the detailed structure of an email, reinforcing the text about the format of email messages according to the Internet standards (RFC 5322). ### Conclusion: The provided images serve as educational tools for understanding the architecture and structure of Internet emails. They illustrate the flow and components of emails as specified by Internet standards, aiding in comprehension of email communication protocols and formats. Both diagrams complement the accompanying textual descriptions, enhancing the reader's grasp of the application layer in computer networking. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 43 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 - The `bcc:` header line is used by the sender to provide a list of comma separated email addresses that must receive a blind carbon copy of the message. The `bcc:` header line is not delivered to the recipients of the email message. A simple email message containing the `From:`, `To:`, `Subject:` and `Date:` header lines and two lines of body is shown below. ``` From: Bob Smith To: Alice Doe , Alice Smith Subject: Hello Date: Mon, 8 Mar 2010 19:55:06 -0600 This is the "Hello World" of email messages. This is the second line of the body. ``` Note the empty line after the `Date:` header line; this empty line contains only the CR and LF characters, and marks the boundary between the header and the body of the message. Several other optional header lines are defined in RFC 5322 and elsewhere. Furthermore, many email clients and servers define their own header lines starting from `X-`. Several of the optional header lines defined in RFC 5322 are worth being discussed here: - The `Message-ID:` header line is used to associate a "unique" identifier to each email. Email identifiers are usually structured like `string@domain` where `string` is a unique character string or sequence number chosen by the sender of the email and `domain` the domain name of the sender. Since domain names are unique, a host can generate globally unique message identifiers concatenating a locally unique identifier with its domain name. - The `In-reply-to:` is used when a message was created in reply to a previous message. In this case, the end of the `In-reply-to:` line contains the identifier of the original message. - The `Received:` header line is used when an email message is processed by several servers before reaching its destination. Each intermediate email server adds a `Received:` header line. These header lines are useful to debug problems in delivering email messages. The figure below shows the header lines of one email message. The message originated at a host named `www.firstpr.com.au` and was received by `smtpm3.sqil.ucl.ac.be`. The `Received:` lines have been wrapped for readability. ``` Received: from smtp3.sqil.ucl.ac.be (unknown [10.1.5.3]) by mmtp.sqil.ucl.ac.be (Sun Java(TM) System Messaging Server 7u3-15.01.64; built Feb 12 2010) with ESMTP id 4X070B5L1S15i.0@dm5m.pir-de.ucl.ac.be; Mon, 08 Mar 2010 11:37:17 +0100 (CET) Received: from mail.inter.net (mail.inter.net [64.170.98.321]) by smtp3.sqil.ucl.ac.be (Postfix) with ESMTP id B9251610B67; Mon, 08 Mar 2010 11:36:51 +0100 (CET) Received: from [127.0.0.1] (localhost [127.0.0.1]) by core03.amsl.com (Postfix) with ESMTP id 1F06A613689; Mon, 08 Mar 2010 02:36:36 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by core03.amsl.com (Postfix) with ESMTP id A166A636AB6; for ; Mon, 08 Mar 2010 02:36:31 -0800 (PST) Received: from mail.etrg.org ([64.170.98.321]) by localhost (core03.amsl.com [127.0.0.1]) (amavis-new, port 10024) with ESMTP for ; Mon, 08 Mar 2010 02:36:36 -0800 (PST) Received: from gair.firstpr.com.au (gair.firstpr.com.au [10.0.1.62.123]) by core03.amsl.com (Postfix) with ESMTP id 0B389A367ED for ; Mon, 08 Mar 2010 02:36:35 -0800 (PST) Received: from [10.0.0.6] (www.firstpr.com.au [10.0.0.6]) by gair.firstpr.com.au (Postfix) with ESMTP id 0A401497563; Mon, 08 Mar 2010 21:36:41 +1100 (EST) Date: Mon, 08 Mar 2010 21:36:39 +1100 ``` The list of all standard header lines may be found at [RFC 5322](http://www.ietf.org/rfc/rfc5322.txt). #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 44 Context: From: Robin Whittle Subject: Re: [rgg] Recommendation and what happens next In-reply-to: To: RSG Message-id: <49B41306.7030508@firstpr.com.au> Message content removed Initially, email was used to exchange small messages of ASCII text between computer scientists. However, with the growth of the Internet, supporting only ASCII text became a severe limitation for two reasons. First of all, non-English speakers wanted to write emails in their native language that often required more characters than those of the ASCII character table. Second, many users wanted to send other content than just ASCII text by email such as binary files, images, or sound. To solve this problem, the IETF developed the Multipurpose Internet Mail Extensions (MIME). These extensions were carefully designed to allow Internet email to carry non-ASCII characters and binary files without breaking the email servers that were deployed at that time. This requirement for backward compatibility forced the MIME designers to develop extensions to the existing email message format RFC 822 instead of defining a completely new format that would have been better suited to support the new types of emails. RFC 2046 defines three types of header lines to support MIME: 1. **MIME-Version:** header indicates the version of the MIME specification that was used to encode the email message. The current version of MIME is 1.0. Other versions of MIME may be defined in the future. 2. **Content-Type:** header line indicates the type of data that is carried inside the message (see below). 3. **Content-Transfer-Encoding:** header line is used to specify how the message has been encoded. When MIME was designed, some email servers were only able to process messages containing characters encoded using the 7 bits ASCII character set. MIME allows the utilisation of other character encodings. Inside the email header, the **Content-Type:** header indicates how the email message is structured. RFC 2046 defines the utilisation of this header line. The two most common structures for MIME messages are: - **Content-Type: multipart/mixed.** This header line indicates that the MIME message contains several independent parts. For example, such a message may contain a part in plain text and a binary. - **Content-Type: multipart/alternative.** This header line indicates that the MIME message contains several representations of the same information. For example, a multipart/alternative message may contain both a plain text and an HTML version of the same text. To support these two types of MIME messages, the recipient of a message must be able to extract the different parts from the message. In RFC 822, an empty line was used to separate the header lines from the body. Using an empty line to separate the different parts of an email body would be difficult as the body of email messages often contains one or more empty lines. Another possible option would be to define a special line, e.g., `--LAST_LINE--`, to mark the boundary between two parts of a MIME message. Unfortunately, this is not possible as some emails may contain this string in their body (e.g., emails sent to students to explain the format of MIME messages). To solve this problem, the **Content-Type:** header line contains a second parameter that specifies the string that has been used by the sender of the MIME message to delineate the different parts. In practice, this string is often chosen randomly by the mail client. The email message below, copied from RFC 2046 shows a MIME message containing two parts that are both in plain text and encoded using the ASCII character set. The string simple boundary is defined in the **Content-Type:** header as the marker for the boundary between two successive parts. Another example of MIME messages may be found in RFC 2046. ``` Date: Mon, 20 Sep 1999 16:31:16 +0200 From: Nathaniel Borenstein To: Ted Fred Subject: Test MIME-Version: 1.0 ``` #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 45 Context: ``` # Computer Networking: Principles, Protocols and Practice, Release 0.25 Content-Type: multipart/mixed; boundary="simple boundary" preamble, to be ignored --simple boundary Content-Type: text/plain; charset=us-ascii ## First part: --simple boundary Content-Type: text/plain; charset=us-ascii ## Second part --simple boundary The `Content-Type:` header can also be used inside a MIME part. In this case, it indicates the type of data placed in this part. Each data type is specified as a type followed by a subtype. A detailed description may be found in RFC 2046. Some of the most popular `Content-Type:` header lines are: - **text**. The message part contains information in textual format. There are several subtypes: `text/plain` for regular ASCII text, `text/html` defined in RFC 2854 for documents in HTML format, or the `text/riched` format defined in RFC 1896. The `Content-Type:` header line may contain a second parameter that specifies the character set used to encode the text. `charset=us-ascii` is the standard ASCII character table. Other frequent character sets include `charset=UTF-8` or `charset=iso-8859-1`. The list of standard character sets is maintained by IANA. - **image**. The message part contains a binary representation of an image. The subtype indicates the format of the image such as `gif`, `jpg` or `png`. - **audio**. The message part contains an audio clip. The subtype indicates the format of the audio clip like `wav` or `mp3`. - **video**. The message part contains a video clip. The subtype indicates the format of the video clip like `avi` or `mp4`. - **application**. The message part contains binary information that was produced by a particular application listed as the subtype. Email clients use the subtype to launch the application that is able to decode the binary data. **Note: From ASCII to Unicode** The first computers used different techniques to represent characters in memory and on disk. During the 1960s, computers began to exchange information via tape or telephone lines. Unfortunately, each vendor had its own proprietary character set and exchanging data between computers from different vendors was often difficult. The 7 bit ASCII character table RFC 20 was adopted by several vendors and by many Internet protocols. However, ASCII became a problem with the internationalization of the Internet and the desire of more and more users to use character sets that support their own written language. A first attempt at solving this problem was the definition of the ISO-8859 character sets by ISO. This family of standards specified various character sets that allowed the representation of many European written languages by using 8 bits characters. Unfortunately, an 8-bits character set is not sufficient to support some widely used languages, such as those used in Asian countries. Fortunately, at the end of the 1980s, several computer scientists proposed to develop a standard that supports all written languages used on Earth today. The Unicode standard (Unicode) has now been adopted by most computer and software vendors. For example, Java uses Unicode natively to manipulate characters. Python can handle both ASCII and Unicode characters. Internet applications are slowly moving towards complete support for the Unicode character sets, but moving from ASCII to Unicode is an important change that can have a huge impact on current deployed implementations. See for example, the work to completely internationalise email RFC 4952 and domain names RFC 5890. ## 3.4 Application-level protocols 41 ``` #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 46 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 of bytes into a set of ASCII lines that can be safely transmitted by email servers. `quoted-printable` is defined in RFC 2045. We briefly describe `base64` which is defined in RFC 2045 and RFC 4648. `Base64` divides the sequence of bytes to be encoded into groups of three bytes (with the last group possibly being partially filled). Each group of three bytes is then divided into four six-bit fields and each six-bit field is encoded as a character from the table below. | Value | Encoding | Value | Encoding | Value | Encoding | |-------|----------|-------|----------|-------|----------| | 0 | A | 17 | R | 34 | i | | 1 | B | 18 | S | 35 | j | | 2 | C | 19 | T | 36 | k | | 3 | D | 20 | U | 37 | l | | 4 | E | 21 | V | 38 | m | | 5 | F | 22 | W | 39 | n | | 6 | G | 23 | X | 40 | o | | 7 | H | 24 | Y | 41 | p | | 8 | I | 25 | Z | 42 | q | | 9 | J | 26 | a | 43 | r | | 10 | K | 27 | b | 44 | s | | 11 | L | 28 | c | 45 | t | | 12 | M | 29 | d | 46 | u | | 13 | N | 30 | e | 47 | v | | 14 | O | 31 | f | 48 | w | | 15 | P | 32 | g | 49 | x | | 16 | Q | 33 | h | 50 | y | The example below, from RFC 4648, illustrates the Base64 encoding. Input data `0x14b0c034976` | B-bit | `00010100 10110000 11010011 11101000` | |---------------------|---------------------------------------| | 6-bit | `000101 001100 001110 1001 111000` | | Decimal | `5 20 28 6 37 62` | | Encoding | `F P u c A 9 +` | The last point to be discussed about `base64` is what happens when the length of the sequence of bytes to be encoded is not a multiple of three. In this case, the last group of bytes may contain one or two bytes instead of three. `Base64` reserves the `=` character as a padding character. This character is used twice when the last group contains two bytes and once when it contains one byte as illustrated by the two examples below. Input data `0x14` | B-bit | `00010100` | |---------------------|-------------------------------------| | 6-bit | `000101 000000` | | Decimal | `5 0` | | Encoding | `F A =` | Input data `0x14b9` | B-bit | `00010100 10111001` | |---------------------|-------------------------------------| | 6-bit | `000101 001011 1100` | | Decimal | `5 11 5` | | Encoding | `F P S` | Now that we have explained the format of the email messages, we can discuss how these messages can be exchanged through the Internet. The figure below illustrates the protocols that are used when Alice sends an email message to Bob. Alice prepares her email with an email client or on a webmail interface. To send her email to Bob, Alice's client will use the Simple Mail Transfer Protocol (SMTP) to deliver her message to her SMTP server. Alice's email client is configured with the name of the default SMTP server for her domain. There is usually at least one SMTP server per domain. To deliver the message, Alice's SMTP server must find the SMTP server that controls Bob's mailbox. This can be done by using the Mail eXchange (MX) records of the DNS. A set of MX records can be associated to each domain. Each MX record contains a numerical preference for the fully qualified domain name of a SMTP server that is able to deliver email messages destined to all valid email addresses of this domain. The DNS can return several MX records for a given domain. In this case, the server with the lowest preference will be used. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 47 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ![Figure 3.14: Email delivery protocols](path/to/image) ## The Simple Mail Transfer Protocol The Simple Mail Transfer Protocol (SMTP) defined in RFC 5321 is a client-server protocol. The SMTP specification distinguishes between five types of processes involved in the delivery of email messages. Email messages are composed on a Mail User Agent (MUA). The MUA is usually either an email client or a webmail. The MUA sends the email message to a Mail Submission Agent (MSA). The MSA processes the received email and forwards it to the Mail Transmission Agent (MTA). The MTA is responsible for the transmission of the email, directly or via intermediate MTAs to the MTA of the destination domain. This destination MTA will then forward the message to the Mail Delivery Agent (MDA) where it will be accessed by the recipient's MUA. SMTP is used for the interactions between MUA and MSA¹, MSA-MTA and MTA-MTA. SMTP is a text-based protocol like many other application-layer protocols on the Internet. It relies on the byte-stream service. Servers listen on port 25. Clients send commands that are each composed of one line of ASCII text terminated by CRLF. Servers reply by sending ASCII lines that contain a three digit numerical error/success code and optional comments. The SMTP protocol, like most text-based protocols, is specified as a BNF. The full BNF is defined in RFC 5321. The main SMTP commands are defined by the BNF rules shown in the figure below. ![Figure 3.15: BNF specification of the SMTP commands](path/to/image) In this BNF, each corresponds to printable ASCII characters. This BNF rule is defined in RFC 5322. The five main commands are `EHLO`, `MAIL FROM:`, `RCPT TO:`, `DATA` and `QUIT`². `Postmaster` is the alias of the system administrator who is responsible for a given domain on SMTP server. All domains must have a `Postmaster` alias. The SMTP responses are defined by the BNF shown in the figure below. SMTP servers use structured reply codes containing three digits and an optional comment. The first digit of the reply code indicates whether the command was successful or not. A reply code of 2yy indicates that the command has been accepted. A reply code of 3yy indicates that the command has been accepted, but additional information is required. 1. During the last years, many Internet Service Providers, campuses and enterprise networks have deployed SMTP extensions (RFC 4950 on their MSAs. These extensions force the MUA to be authenticated before the MSA accepts an email message from the MUA. 2. The first version of SMTP used `EHLO` as the command used to identify a SMTP server. When SMTP was extended to support newer features such as 8 bit characters, it was necessary to allow a server to recognize whether it was interacting with a client that supported the extensions or not. `EHLO` became mandatory with the publication of RFC 2821. ## 3.4 Application-level protocols **[Page 43]** Image Analysis: ### Analysis of the Attached Visual Content ### 1. Localization and Attribution - **Image 1**: - Located at the top center of the document. - Captioned as "Figure 3.14: Email delivery protocols." - **Image 2**: - Located slightly below the midpoint, center of the document. - Captioned as "Figure 3.15: BNF specification of the SMTP commands." ### 2. Object Detection and Classification #### Image 1: - **Objects Detected**: - Two computers labeled "Alice@a.net" and "Bob@b.net." - Arrows labeled "SMTP" and "Email retrieval" pointing from one computer to the other. - Two servers: "a.net’s SMTP server" and "b.net’s SMTP server." #### Image 2: - **Objects Detected**: - Text-based representation of SMTP commands and responses. - Structured in a tree-like diagram depicting different commands and replies. ### 3. Scene and Activity Analysis #### Image 1: - **Scene**: - The image depicts the sequence of email delivery protocols, showing the interactions between different servers and devices. - **Activity**: - Alice@a.net sends an email via a.net’s SMTP server. - The email is then routed to b.net’s SMTP server. - Bob@b.net retrieves the email from the b.net server using IMAP (or POP). #### Image 2: - **Scene**: - The image shows the BNF (Backus-Naur Form) specification of the main SMTP commands and their respective responses. - **Activity**: - Different SMTP commands (`HELO`, `MAIL FROM`, `RCPT TO`, `DATA`, `QUIT`) are structured and detailed with the expected server responses. ### 4. Text Analysis #### Image 1: - No significant text other than labels (SMTP, IMAP, PO3, server names) which inform about the protocols and server roles in the email delivery process. #### Image 2: - **Detected Text**: - *SMTP Command Specifications*: Detailed depiction of how SMTP works using BNF. - Commands include `HELO`, `MAIL FROM`, `RCPT TO`, `DATA`, and `QUIT`. - Server responses structured with numerical codes indicating success or failure. ### 6. Product Analysis - **Not applicable**: No physical products shown. ### 9. Perspective and Composition #### Both Images: - **Perspective**: - Image 1: Diagrammatic representation, neutral top-down perspective. - Image 2: Conceptual diagram showing command structures. - **Composition**: - Image 1: Elements are organized sequentially to show the ordered process of email delivery. - Image 2: Structured to visually represent command hierarchy and responses clearly, aiding in understanding SMTP command rules. ### 11. Metadata Analysis - **Not available**: Metadata not provided in the image. ### 12. Graph and Trend Analysis - **Not applicable**: No graphs present. ### Additional Aspects #### Ablaufprozesse (Process Flows): - **Email delivery** in Image 1: Sequential process shown for how an email travels across networks. #### Prozessbeschreibungen (Process Descriptions): - **SMTP Command Processing** in Image 2: - `HELO`: Client identifying itself to the server. - `MAIL FROM`: Specifying the sender. - `RCPT TO`: Specifying the recipient. - `DATA`: Transmitting the email body. - `QUIT`: Terminating the session. #### Typen Bezeichnung (Type Designations): - **Types/Categories**: - Email Protocols: SMTP, IMAP, POP. - SMTP Commands: HELO, MAIL FROM, RCPT TO, DATA, QUIT. #### Trend and Interpretation: - **Email Protocol Usage**: Emphasis on how SMTP is structured to standardize email transfer. ### Summary: The visual content comprises two main images related to topics on email delivery protocols and SMTP command processing. They illustrate different aspects of how emails are transmitted and received across network servers, complying with specific command protocols. The detailed breakdown of SMTP commands and their BNF specifications help in understanding the procedural workflows involved in email communications. No anomalies or unusual elements were detected. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 48 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## Figure 3.16: BNF Specification of the SMTP Responses Information from the client is expected. A reply code of 4xy indicates a transient negative reply. This means that for some reason, which is indicated by either the other digits or the comment, the command cannot be processed immediately, but there is some hope that the problem will only be transient. This is basically telling the client to try the same command again later. In contrast, a reply code of 5xy indicates a permanent failure or error. In this case, it is useless for the client to retry the same command later. Other application layer protocols such as FTP (RFC 959) or HTTP (RFC 2616) use a similar structure for their reply codes. Additional details about the other reply codes may be found in RFC 5321. ### Examples of SMTP Reply Codes Include the Following: - **500**: Syntax error, command unrecognized - **501**: Syntax error in parameters or arguments - **502**: Command not implemented - **503**: Bad sequence of commands - **504**: Domain service ready - **211**: Service closing transmission channel - **421**: Service not available, closing transmission channel - **250**: Requested mail action okay, completed - **450**: Requested mail action not taken: mailbox unavailable - **452**: Requested action not taken: insufficient system storage - **550**: Requested action not taken: mailbox unavailable - **554**: Start mail input; end with . The first four reply codes correspond to errors in the commands sent by the client. The fourth reply code would be sent by the server when the client sends commands in an incorrect order (e.g., the client tries to send an email before providing the destination address of the message). Reply code 220 is used by the server as the first message after it agrees to interact with the client. Reply code 221 is sent by the server before closing the underlying transport connection. Reply code 421 is returned when there is a problem (e.g., lack of memory/disks resources) that prevents the server from accepting the transport connection. Reply code 250 is the standard positive reply that indicates the success of the previous command. Reply codes 450 and 452 indicate that the destination mailbox is temporarily unavailable, for various reasons, while reply code 550 indicates that the mailbox does not exist or cannot be used for policy reasons. Reply code 554 indicates that the client can start transmitting its email message. The transfer of an email message is performed in three phases. During the first phase, the client tries to establish a connection with the server. Once the connection has been established, the client and the server exchange greetings messages (EHLO command). Most servers insist on receiving valid greeting messages and some of them drop the underlying transport connection if they do not receive a valid greeting. Once the greetings have been exchanged, the email transfer phase can start. During this phase, the client transfers one or more email messages by indicating the email address of the sender (MAIL FROM: command), the email address of the recipient (RCPT TO: command) followed by the headers and the body of the email message (DATA command). Once the client has finished sending all its queued email messages to the SMTP server, it terminates the SMTP session (QUIT command). ### A Successful Transfer of an Email Message is Shown Below: ``` C: 220 smtp.example.com ESMTP NTA information C: EHLO example.org S: 250 Hello alma.example.org, glad to meet you C: MAIL FROM: S: 250 OK C: RCPT TO: S: 250 OK C: DATA S: 354 End data with . C: From: "Alice Doe" C: To: Bob Smith C: Date: Mon, 9 Mar 2010 18:22:32 +0100 C: ``` Image Analysis: ### Analysis of Attached Visual Content #### Localization and Attribution: - **Image Identification**: Single image on the page, labeled as *Image 1*. Localization is at the top half of the page. #### Object Detection and Classification: - **Detected Objects**: Diagram, text, and table. - **Diagram**: A flowchart-like illustration titled "Figure 3.16: BNF specification of the SMTP responses". - **Text**: Descriptive paragraphs and examples explaining SMTP responses, including a demonstrative sequence of SMTP commands and their responses. - **Table**: Listings of SMTP reply codes and their descriptions. #### Scene and Activity Analysis: - **Scene Description**: The image is an instructional screenshot from a textbook or instructional document focused on computer networking. The scene includes a figure depicting SMTP responses, explanatory text, and a practical example of SMTP commands. - **Activity**: The primary activity is educational, aimed at instructing readers about SMTP (Simple Mail Transfer Protocol) responses and how they operate within email communications. #### Text Analysis: - **Detected Text**: - **Diagram Labels**: "Creating", "Receiving", "Sending", and their respective reply codes. - **Paragraphs**: Explanations of reply codes, examples of SMTP reply codes, detailed descriptions, and an SMTP command sequence example. - **Significance**: - **Explanational**: Text provides detailed descriptions of various SMTP reply codes and their meanings, supporting the comprehension of SMTP behaviors. - **Educational**: The example SMTP dialogue helps reinforce the textual information, offering practical understanding through simulation. #### Diagram and Chart Analysis: - **Diagram Description**: - **Axes, Scales, and Legends**: Not applicable. Instead, a flowchart-like structure details the SMTP responses, divided into categories based on functions (Creating, Receiving, Sending). - **Data and Trends**: The diagram classifies SMTP reply codes into groups for organization, showing how different activities and states (creating, receiving, sending) are mapped to specific reply codes. - **Key Insights**: This diagram aids in visualizing which part of the email transaction each reply code corresponds to, making it easier for readers to understand where issues may arise during the SMTP communication process. #### Product Analysis: - **Described Products**: Not applicable. #### Anomaly Detection: - **Possible Anomalies**: None detected. All elements seem purposeful and in alignment with the instructional nature of the document. #### Color Analysis: - **Dominant Colors**: Black text on a white background, which is typical for educational documents to ensure high readability. #### Perspective and Composition: - **Perspective**: Standard 2D view from above, typical for textual and diagrammatic educational material. - **Composition**: The content is arranged linearly, with the diagram at the top, followed by explanatory text, and ending with practical examples. This logical flow aids in understanding SMTP responses progressively from conceptual to practical application. #### Contextual Significance: - **Overall Contribution**: The image significantly contributes to the chapter on 'The Application Layer' by providing a detailed and clear explanation of SMTP responses. It supports the educational objective of the text. #### Metadata Analysis: - **Available Metadata**: Not applicable. #### Graph and Trend Analysis: - **Data and Trends**: Not applicable. #### Graph Numbers: - **Data Points**: Not applicable. #### Ablaufprozesse (Process Flows): - **Process Description**: The flow of SMTP commands and responses follows a linear transactional model, depicted in text and the figure to aid in understanding the protocol's operations. #### Prozessbeschreibungen (Process Descriptions): - **Detailed Process**: The described process includes the sending of EHLO command, interaction through MAIL/RCPT, and ending with DATA and QUIT commands, simulating a complete SMTP session. #### Typen Bezeichnung (Type Designations): - **Type Specifications**: Categorization of SMTP reply codes into functions (Creating, Receiving, Sending, etc.). #### Trend and Interpretation: - **Identified Trends**: Standardization and categorization of SMTP responses facilitate managing and troubleshooting email communication effectively. #### Tables: - **Content and Data**: The table lists SMTP reply codes and their descriptions (e.g., "501 Syntax error in parameters or arguments"). - **Significance**: Provides quick references for identifying and resolving issues based on the SMTP server's responses. ### Conclusion The image serves as a pivotal educational tool in understanding SMTP responses within the chapter focused on 'The Application Layer,' offering visual, textual, and practical insights into email transactions and error handling in networking. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 49 Context: ``` C: Subject: Hello C: Hello Bob C: This is a small message containing 4 lines of text. C: Best regards, C: Alice C: C: 250 OK: queued as 12345 C: 2017 C: 221 Bye In the example above, the MTA running on `mta.example.org` opens a TCP connection to the SMTP server on host `smtp.example.com`. The lines prefixed with `S:` (resp. `C:`) are the responses sent by the server (resp. the commands sent by the client). The server sends its greetings as soon as the TCP connection has been established. The client then sends the `EHLO` command with its fully qualified domain name. The server replies with reply-code `250` and sends its greetings. The SMTP association can now be used to exchange an email. To send an email, the client must first provide the address of the recipient with `RCPT TO:`. Then it uses the `MAIL FROM:` with the address of the sender. Both the recipient and the sender are accepted by the server. The client can now issue the `DATA` command to start the transfer of the email message. After having received the `354` reply code, the client sends the headers and the body of its email message. The client indicates the end of the message by sending a line containing only the `.` (dot) character. The server confirms that the email message has been queued for delivery or transmission with a reply code of `250`. The client issues the `QUIT` command to close the session and the server confirms with reply-code `221`, before closing the TCP connection. Note: **Open SMTP relays and spam** Since its creation in 1971, email has been a very useful tool that is used by many users to exchange lots of information. In the early days, all SMTP servers were open and anyone could use them to forward emails towards their final destination. Unfortunately, over the years, some unscrupulous users have found ways to use email for marketing purposes or to send malware. The first documented abuse of email for marketing purposes occurred in 1978 when a marketer who worked for a computer vendor sent a marketing email to many ARPANET users. At that time, the ARPANET could only be used for research purposes and this was an abuse of the acceptable use policy. Unfortunately, given the extremely low cost of sending emails, the problem of unsolicited emails has not stopped. Unsolicited emails are now called spam and a study carried out by ENISA in 2009 revealed that 95% of email spam was sent by this number seems to continue to grow. This places a burden on the email infrastructure of Internet Service Providers and large companies that need to process many messages daily. Given the amount of spam messages, SMTP servers are no longer open for public use. Several extensions to SMTP have been developed in recent years to deal with this problem. For example, the SMTP authentication scheme defined in RFC 4954 can be used by an SMTP server to authenticate a client. Several techniques have also been proposed to allow SMTP servers to authenticate the messages sent by their users RFC 4870 RFC 4871. ## The Post Office Protocol When the first versions of SMTP were designed, the Internet was composed of minicomputers that were used by an entire university department or research lab. These minicomputers were used by many users at the same time. Email was mainly used to send messages from a user on a given host to another user on a remote host. At that time, SMTP was the only protocol involved in the delivery of emails as it also attached to the network for running an SMTP server. On such host, an email destined to local users was delivered by placing the email in a special directory of die owned by the user. However, the introduction of personal computers in the 1980s changed this environment. Initially, users of these personal computers used applications such as telnet to open a remote session on the local minicomputer to read their email. This was not user-friendly. A better solution appeared with the development of user-friendly email client applications on personal computers. Several protocols were designed to allow these client applications to retrieve the email messages destined to a user from his/her server. Two of these protocols became popular and are still used today. The Post Office Protocol (POP), defined in RFC 1939. ``` #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 50 Context: # Computer Networking: Principles, Protocols and Practice, Release 0.25 ## 3. Part 2: The Application Layer Post Office Protocol (POP) is the simplest one. It allows a client to download all the messages destined to a given user from his/her email server. We describe POP briefly in this section. The second protocol is the Internet Message Access Protocol (IMAP), defined in RFC 3501. IMAP is more powerful, but also more complex than POP. IMAP was designed to allow client applications to efficiently access in real-time to messages stored in various folders on servers. IMAP assumes that all the messages of a given user are stored on a server and provides the functions that are necessary to search, download, delete, or alter messages. ### POP Overview POP is another example of a simple line-based protocol. POP runs above the bytestream service. A POP server usually listens to port 110. A POP session is composed of three parts: 1. **Authorisation phase**: During which the server verifies the client's credential, a transaction phase during which the client downloads messages and an update phase that concludes the session. The client sends commands and the server replies are prefixed by `+OK` to indicate a successful command or `-ERR` to indicate errors. When a client opens a transport connection with the POP server, the latter sends a banner an ASCII-line starting with `+OK`. The POP session is at that time in the authorisation phase. In this phase, the client can send its username (resp. password) with the `USER` (resp. `PASS`) command. The server replies with `+OK` if the username (resp. password) is valid and `-ERR` otherwise. Once the username and password have been validated, the POP session enters the transaction phase. In this phase, the client can issue several commands. The `STAT` command is used to retrieve the status of the server. Upon reception of this command, the server replies with a line that contains `+OK` followed by the number of messages in the mailbox and the total size of the mailbox in bytes. The `RETR` command, followed by a space and an integer, is used to retrieve the nth message of the mailbox. The `DELE` command is used to mark for deletion the nth message from the mailbox. Once the client has retrieved and possibly deleted the emails contained in the mailbox, it must issue the `QUIT` command. This command terminates the POP session and allows the server to delete all the messages that have been marked for deletion by using the `DELE` command. ### Example POP Session The figure below provides a simple POP session. All lines prefixed with `C:` (resp. `S:`) are sent by the client (resp. server). ``` S: +OK POP3 server ready C: USER alice S: +OK C: PASS 1234pass S: +OK Alice's maildrop has 2 messages (620 octets) C: STAT S: +OK 2 620 C: LIST S: +OK 2 messages (620 octets) S: 1 120 S: 2 500 C: C: RETR 1 S: +OK 120 octets S: . C: DELE 1 S: +OK message 1 deleted C: QUIT S: +OK POP3 server signing off (1 message left) ``` In this example, a POP client contacts a POP server on behalf of the user named alice. Note that in this example, Alice's password is sent in clear by the client. This implies that if someone is able to capture the packets sent by Alice, he will know Alice's password. Then Alice's client issues the `STAT` command to know the number of messages that are stored in her mailbox. It then retrieves and deletes the first message of the mailbox. **RFC 1939** defines the POP authentication scheme that is not vulnerable to such attacks. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 51 Context: # 3.4.3 The HyperText Transfer Protocol In the early days of the Internet was mainly used for remote terminal access with telnet, email and file transfer. The default file transfer protocol, FTP, defined in RFC 959 was widely used and FTP clients and servers are still included in most operating systems. Many FTP clients offer a user interface similar to a Unix shell and allow the client to browse the file system on the server and to send and retrieve files. FTP servers can be configured in two modes: - **authenticated**: in this mode, the FTP server only accepts users with a valid user name and password. Once authenticated, they can access the files and directories according to their permissions. - **anonymous**: in this mode, clients supply the anonymous userid and their email address as password. These clients are granted access to a special zone on the file system that only contains public files. FTP was very popular in the 1990s and early 2000s, but today it has mostly been superseded by more recent protocols. Authenticated access to files is mainly done by using the Secure Shell (SSH) protocol defined in RFC 4251 and supported by clients such as SCP or SFTP. Nowadays, anonymous access is mainly provided by web protocols. In the late 1980s, high energy physicists working at CERN had to efficiently exchange documents about their ongoing and planned experiments. Tim Berners-Lee evaluated several of the document sharing techniques that were available at the time [B1989]. As none of the existing solutions met CERN's requirements, they chose to develop a completely new document sharing system. This system was initially called the mesh, but was quickly renamed the **World Wide Web**. The starting point for the **World Wide Web** are hypertext documents. An hypertext document is a document that contains references (hyperlinks) to other documents that the reader can immediately access. Hypertext was not invented for the World Wide Web. The idea of hypertext documents was proposed in 1945 [Bush1945] and the first experiments were done during the 1960s [Nelson1965][Myers1998]. Compared to the hypertext documents that were used in the late 1980s, the main innovation introduced by the **World Wide Web** was to allow hyperlinks to reference documents stored on remote machines. ![Figure 3.17: World-wide web clients and servers](server_image.png) A document sharing system such as the **World Wide Web** is composed of three important parts: 1. A standardised addressing scheme that allows unambiguous identification of documents 2. A standard document format: the **HyperText Markup Language** 3. A standardised protocol that facilitates efficient retrieval of documents stored on a server **Note:** Open standards and open implementations # 3.4. Application-level protocols 47 Image Analysis: ### Analysis of the Attached Visual Content #### 1. **Localization and Attribution:** - **Image Position:** - There is only one image on the page. - It is located at the bottom center of the page. - **Numbering:** - Image Number: Image 1. #### 2. **Object Detection and Classification:** - **Objects Identified in Image 1:** - Servers - Client (Browser) - Queries and Responses (represented with arrows) - **Classification:** - **Servers:** Represented as computer towers, indicating web servers. - **Client (Browser):** Represented by a single computer, indicating the end-user device. - **Queries/Responses:** Represented by colored arrows showing information flow between the client and servers. #### 3. **Scene and Activity Analysis:** - **Scene Description:** - The image depicts a simplified diagram of the interactions between a web client (browser) and multiple web servers. - **Activities:** - The client (browser) sends requests (queries) to different servers. - Servers then send back responses. - **Main Actors:** - Client (Browser) - Server www.example.be - Server www.cern.ch - Server www.vsllfl.com #### 4. **Text Analysis:** - **Detected Text:** - Title: "Figure 3.17: World-wide web clients and servers" - Annotation: - "Client (Browser)" - "Query" (with arrows pointing towards servers) - "Response" (with arrows pointing back to the client) - Server addresses: "www.example.be", "www.cern.ch", "www.vlsllfl.com" - **Significance:** - The text provides context and labels for understanding the flow of data between the client and servers, illustrating the basic operation of web browsing. #### 5. **Diagram and Chart Analysis:** - **Data and Trends:** - The diagram exemplifies the principle of client-server interaction in web communication. - **Axes, Scales, Legends:** - Not applicable, as this is not a graph with axes but a schematic diagram. - **Key Insights:** - Clients make requests to multiple servers and receive responses back, depicting how web communications work in retrieving information from various sources. #### 8. **Color Analysis:** - **Color Composition:** - Dominant colors include blue (for arrows indicating queries) and red (for arrows indicating responses). - Servers and the client are depicted in neutral colors (grey), making the flow of data the focal point. #### 9. **Perspective and Composition:** - **Perspective:** - The image is presented from a low angle view that places the servers in focus, illustrating their central role in data provision. - **Composition:** - Centralized layout with the client at the bottom and servers at the top. - Arrows (both blue and red) effectively show the direction of data flow. #### 10. **Contextual Significance:** - **Overall Message:** - The figure supports the text's explanation of the HyperText Transfer Protocol (HTTP) by visually demonstrating how clients interact with multiple web servers to retrieve web documents. #### 12. **Graph and Trend Analysis:** - **Trends and Interpretation:** - No specific numerical trends; rather, it illustrates the qualitative trend of request-response cycles in web communication. #### **Additional Aspects:** - **Ablaufprozesse (Process Flows):** - The process flow of client-server interaction via HTTP is depicted, demonstrating the query-response sequence critical for web access. - **Prozessbeschreibungen (Process Descriptions):** - Describes the process where a client (browser) sends requests to servers and servers provide the requested data back to the client. --- This examination of the visual content provides a detailed understanding of the image's placement, components, significance, and contribution to the document’s overall theme on web protocols and client-server interactions. #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 52 Context: Open standards have played, and continue to play, a key role in the success of the world wide web as we know it today. Without open standards, the world wide web would never have reached its current size. In addition to open standards, another important factor for the success of the web was the availability of open and efficient implementations of these standards. When CERN started to work on the web, their objective was to build a running system that could be used by physicists. They developed open-source implementations of the first web servers and web clients. These open-source implementations were powerful and could be used as is, by institutions willing to share information on the web. They were also extended by other developers who contributed to new features. For example, NCSA added support for images in their Mosaic browser that was eventually used to create Netscape Communications. The first components of the world wide web are the Uniform Resource Identifiers (URI), defined in RFC 3966. A URI is a character string that unambiguously identifies a resource on the world wide web. Below is a subset of the BNF for URIs: ``` URI ::= scheme ":" "//" authority path [ "?" query ] [ "#" fragment ] scheme ::= ALPHA | ALPHA ( ALPHA | DIGIT | "+" | "-" | "." )* authority ::= userinfo "@" host [ ":" port ] query ::= pchar / segmentation fragment ::= pchar / segment pchar ::= unreserved / pct-encoded / sub-delims / ":" / "@" segment ::= pchar / "/" * path ::= "/" [ segment ( "/" segment )* ] pct-encoded ::= "%" HEXDIG HEXDIG unreserved ::= ALPHA | DIGIT | "-" | "." | "_" | "~" reserved ::= gen-delims / sub-delims gen-delims ::= ":" | "/" | "?" | "#" | "[" | "]" | "@" sub-delims ::= "!" | "$" | "&" | "'" | "(" | ")" | "*" | "+" | "," | ";" | "=" ``` The first component of a URI is its **scheme**. A scheme can be seen as a selector, indicating the meaning of the fields after it. In practice, the scheme often identifies the application-layer protocol that must be used by the client to retrieve the document, but it is not always the case. Some schemes do not imply a protocol at all and some do not indicate a retrievable document. The most frequent scheme is http that is described later. A URI should be considered valid for any application layer protocol (rundefined). The characters `:` and `//` follow the scheme and end it. The second part of the URI is the **authority**. With retrievable URIs, this includes the DNS name or the IP address of the server where the document can be retrieved using the protocol specified via the scheme. This name can be preceded by some information about the user (e.g., a user name) who is requesting the information. The definitions of the URI allowed the specification of a user name and a password before the colon (RFC 1738), but this is now deprecated as placing a password inside a URI is insecure. The host can be followed by the semicolon character and a port number. A default port number is defined for some protocols and the port number should only be included in the URI if a non-default port number is used (for example, techniques like service DNS records are used). The third part of the URI is the **path** to the document. This path is structured as filenames on a Unix (but not it does not imply that the files are indeed stored this way on the server). If the path is not specified, the server will return a default document. The last two optional parts of the URI are used to provide a query and indicate a specific resource (e.g., a section in an article) of the requested document. Sample URIs are shown below. ``` http://tools.ietf.org/html/rfc3986.html http://infodotexample.com/subset/current-issue https://docs.python.org/library/basehttpserver.html?highlight=http#BaseHTTPServer.BaseHTTPRequestHandler telnet://[201:68:300:18:22:80]/ ftp://svn.example.com/something_news%10.0.1.0/tcp_story.htm ``` The first URI corresponds to a document named `rfc3986.html` that is stored on the server named `tools.ietf.org` and can be accessed by using the `http` protocol on its default port. The second URI corresponds to an email message (see RFC 3180). Of course, any URI can be made retrievable via a dedicated server or a proxy that has no explicit protocol call. Same thing for the scheme (see for example RFC 4151), others need to be specified in compliance with the Atom syndication format. Even when the scheme is retrievable (for instance with http), it is often used only as an identifier, not as a way to get a resource. See http://www.w3.org/2002/07/rdf-syntax-grammar# and /addresses for a good explanation. Chapter 3: Part 2: The Application Layer #################### File: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf Page: 53 Context: # Computer Networking : Principles, Protocols and Practice, Release 0.25 With subject `current-issue`, that will be sent to user info@example.com. The `mailto:` URI scheme is defined in RFC 6068. The third URI references the portion `baseHTTPSeResources` of the document `basehref=example.html` that is stored in the library directory on server `docs.python.org`. This document can be retrieved by using the http protocol. The query string `highlight=isp` is associated to this URL. The fourth example is a server that operates the telnet protocol, uses IPv6 address `2001:0db8:0000:0042:0000:0000:0c0d:001a`, and is reachable on port 80. The last URI is somewhat special. Most users will assume that it corresponds to a document stored on the `cn.example.com` server. However, to parse this URI, it is important to remember that the `@` character is used to separate the user name from the host name in the authorization part of a URI. This implies that the URI points to a document named `app_story.htm` on host having IPv4 address `10.0.0.1`. The document will be retrieved by using the ftp protocol with the user name set to `cn.example.com/story-breaking_news`. The second component of the **world wide web** is the HyperText Markup Language (HTML). HTML defines the format of the documents that are exchanged on the web. The first version of HTML was derived from the Standard Generalized Markup Language (SGML), which was standardised in 1986 by ISO. SGML was designed to allow large project documents in industries such as government, law or aerospace to be shared efficiently in a machine-readable manner. These industries require documents to remain readable and editable for tens of years and insisted on a standardised format supported by multiple vendors. Today, SGML is no longer widely used beyond specific applications, but its descendants including HTML and XML are now widespread. A markup language is a structured way of adding annotations about the formatting of the document within the document itself. Example markup languages include HTML, which is used to write the Unix man pages or LaTeX. HTML uses elements to annotate text and a document is composed of **nested** HTML elements. Each element is composed of three items: a start tag that potentially includes some specific attributes, some text (including other elements), and an end tag. A HTML tag is a keyword enclosed in angle brackets. The generic form of a HTML element is: ```html Some text to be displayed ``` More complex HTML elements can also include optional attributes in the start tag: ```html Some text to be displayed ``` The HTML document shown below is composed of two parts: a header, delineated by the `` and `` markers, and a body (between the `` and `` markers). In the example below, the header only contains a title, but other types of information can be included in the header. The body contains an image, some text and a list with three hyperlinks. The image is included in the web page by indicating its URI between brackets inside the `` marker. The image can, of course, reside on any server and the client will automatically download it when rendering the web page. The `
    `...
marker is used to specify the first level of headings. The `
    ` marker indicates an unnumbered list while the `
  • ` marker indicates a list item. The `` indicates a hyperlink. The text will be underlined in the rendered web page and the client will fetch the specified URI when the user clicks on the link. ```html HTML test page

    Some web servers

    Some web servers:

    ``` Figure 3.18: A simple HTML page Additional details about the various extensions to HTML may be found in the official specifications maintained by W3C. The third component of the **world wide web** is the HyperText Transport Protocol (HTTP). HTTP is a text-based protocol used for distributed, collaborative, hypermedia information systems. ## 3.4 Application-level protocols Image Analysis: ### Comprehensive Examination of the Attached Visual Content #### 1. **Localization and Attribution:** - **Image 1:** Located in the lower middle section of the page. Identified for analysis. #### 2. **Object Detection and Classification:** - **Image 1:** - Objects Detected: - Box diagrams with HTML tags and attributes. - Annotated lines linking to the body of the text. - Textual annotations and labels. - Key Features: - The image contains a structured example of HTML code with annotations describing various parts like headers, body, and links. #### 3. **Scene and Activity Analysis:** - **Image 1:** - Scene Description: The image showcases a simple HTML page structure with annotations highlighting different elements such as header, body, and links. - Activities: The image is used in a tutorial context to explain HTML code structure and web page elements. #### 4. **Text Analysis:** - **Page Content:** - **Headers:** - "Computer Networking: Principles, Protocols and Practice, Release 0.25" - **Body Text:** - Detailed description of Uniform Resource Identifiers (URIs) and their usage in HTML documents, HTML's evolution, and various HTML tags. - **Text in Image 1:** - "" - "" - "HTML test page" - "" - "

    Some web servers

    " - "" - "" - "" - "" - Annotated lines: "Image on remote server", "First level title", "Unnumbered list", "External hyperlink link". #### 5. **Diagram and Chart Analysis:** - **Image 1:** - Diagram showing the structural breakdown of an HTML document. - Annotations provide insight into HTML elements like headers and body content, including images and hyperlinks. #### 9. **Perspective and Composition:** - **Image 1:** - Perspective: Straight-on view. - Composition: The HTML code is centrally positioned, with annotation lines branching off to explain different parts, creating a clear and organized layout. #### 10. **Contextual Significance:** - **Overall Document Context:** - The image and accompanying text appear to be part of a tutorial or educational material on networking protocols and web development. - It contributes to understanding the structure and components of an HTML document, emphasizing the basics of web page construction. #### 13. **Graph Numbers:** - **Image Text (HTML code):** - "" - "" - "HTML test page" - "" - "

    Some web servers

    " - "" - "" - "" - "" #### **Ablaufprozesse (Process Flows):** - **Process Flow of HTML Rendering:** - Explanation of how HTML tags are used to structure content for rendering web pages. - Detailed breakdown of header and body regions in HTML documents. #### **Prozessbeschreibungen (Process Descriptions):** - Descriptions of how different HTML tags interact to form a web page: - `` encloses the page content. - `` contains meta-information. - `` includes visible page content. #################### File: amag-ch-28917.txt Page: 1 Context: ELECTROMOBILITY switch now AMAG GROUP Mobility, Sustainability & Future NO. 1 CAR DEALER IN SWITZERLAND with 90 locations Find a vehicle Services Find garage Jobs My garage EN Online-Leasing Discover our exclusive online leasing deals Profit now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. New CUPRA Formentor Discover now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. The new Audi Q6 e-tron from CHF 570.–/month* Discover now Full charge of rE-volution from a single source Discover now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. Fast help in the event of damage Report a damage online now The new Å koda Kodiaq Test drive now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. The new Tiguan Discover now Envia – on the road at home with the camper from AMAG Take a closer look! New Formentor Q6 e-tron 360 Grad Lösungen Schadenmeldung Video New Kodiaq New Tiguan Envia Find a vehicle Services Find garage Our vehicles Find and buy your car now directly online. #################### File: amag-ch-28917.txt Page: 1 Context: Find and buy your car now directly online. All brands VW Audi SEAT, CUPRA CUPRA Å koda VW Commercial Vehicles All brands Brand All models All models Model All Sedan Station wagon Convertible Coupé Van/minibus SUV/off-road vehicle Pickup Commercial vehicle/camper All Construction type All prices Until CHF 1'000 Until CHF 2'000 Until CHF 3'000 Until CHF 4'000 Until CHF 5'000 Until CHF 7'500 Until CHF 10'000 Until CHF 12'500 Until CHF 15'000 Until CHF 17'500 Until CHF 20'000 Until CHF 22'500 Until CHF 25'000 Until CHF 30'000 Until CHF 35'000 Until CHF 40'000 Until CHF 45'000 Until CHF 50'000 Until CHF 60'000 Until CHF 70'000 Until CHF 80'000 Until CHF 90'000 Until CHF 100'000 Until CHF 150'000 Until CHF 200'000 Until CHF 300'000 All prices Price until Find vehicles AMAG AMAG NEWS CUPRA PROMOTION The new CUPRA Formentor VZ e-HYBRID from CHF 450.–/month Pure passion Discover now SEAT PROMOTION The SEAT Ibiza Sensacion from CHF 250.– per month with no down payment Experience pure driving pleasure Discover now DYNAMIC. STIRRING. AMPLE. The Audi A1 Sportback from CHF 239.- per month Discover now ONLY FOR A SHORT TIME Discover our exclusive online deals Profit now Show more WELCOME TO AMAG From purchase via service to sale of your car – at AMAG you will find what you’re looking for Your dream car from AMAG 1 / 3 Buy or lease a car #################### File: amag-ch-28917.txt Page: 1 Context: Find what you’re looking for here. Discover all the offers from your AMAG! Find out more AMAG car subscription Get your dream car for a flat price per month - everything except fuel included. Find out more Sell a car Make room for new dreams. We buy your car. Find out more Our services for you 1 / 3 Your online appointment Without detours directly online on the desired date at an AMAG garage of your choice. Arrange an appointment Top garage services Quality and speed: our service and workshop staff are here for you. Find out more Help in case of damage Whether breakdown or hail damage. We are here for you 24/7. Find out more SERVICES Our most requested services The best service brings highest safety and comfort. How can we be of further assistance? Tyres and wheels Summer tyre change Winter tyre change Complete wheels All-season tyres About the service Air conditioning service Cleaning Fluid check Functional check About the service Car service / maintenance Mobility guarantee Original spare parts Maintenance of the warranty About the service Arrange an appointment I was able to easily and conveniently book my appointment online. Thank you for the amazing service! Regula S. Customer of AMAG Our AMAG pledge Full transparency Largest selection of vehicles Free test drive Buy a vehicle online with just a few clicks Fair trade-in price Greater safety 15 day right of exchange for used vehicles Quality check Minimum 12-month warranty Totalmobil! vehicle insurance Best service Breakdown assistance 24h Highest service quality Attractive financing options Individual insurance packages Turn your passion into a profession Do you have ambitious goals? Take your chance and find your dream job at AMAG. About the jobs AMAG – your car dealership at 90 locations and online #################### File: amag-ch-28917.txt Page: 1 Context: About the jobs AMAG – your car dealership at 90 locations and online Welcome to the biggest car dealership in Switzerland. As official Swiss dealership, we at AMAG offer you all the models of all the Volkswagen brands. At AMAG, you will find online and on site a huge range of new, stock and used vehicles from car brands like Volkswagen, Audi, SEAT, Å koda, CUPRA, VW Commercial Vehicles and Bentley. Of course, our experts also offer all the services related to the car after the purchase – be it a repair in the workshop or a consultation at the garage! Buy vehicles directly online To sell your car to AMAG All-round service for your car Find the AMAG garage of your choice Assistance & contact Contact Online appointment FAQ Online car purchase Corporate clients Newsletter Emergency Find a car & service Find a vehicle Services Find garage Car subscription Clyde Leasing Europcar Carsharing Company About us AMAG Group Sustainability Jobs & careers Press Our brands AMAG App Get connected with AMAG © 2024 AMAG Automobil und Motoren AG Privacy policy Legal notice Impressum Terms and conditions Cookie policy Jobs We use cookies to optimise the experience on our website. This includes the personalisation of content and ads, offering social networking features and traffic analysis. Such cookies include targeted social media cookies and cookies for advanced analysis. For more information, please see our information note on the cookie page. By clicking “Accept” you agree to our use of cookies. To change the types of cookies we use, please click on “Cookie settings”. Further information on data protection can be found here. Cookies Settings Reject all Accept all #################### File: amag-ch-28917.txt Page: 1 Context: ELECTROMOBILITY switch now AMAG GROUP Mobility, Sustainability & Future NO. 1 CAR DEALER IN SWITZERLAND with 90 locations Find a vehicle Services Find garage Jobs My garage EN Online-Leasing Discover our exclusive online leasing deals Profit now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. New CUPRA Formentor Discover now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. The new Audi Q6 e-tron from CHF 570.–/month* Discover now Full charge of rE-volution from a single source Discover now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. Fast help in the event of damage Report a damage online now The new Å koda Kodiaq Test drive now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. The new Tiguan Discover now Envia – on the road at home with the camper from AMAG Take a closer look! New Formentor Q6 e-tron 360 Grad Lösungen Schadenmeldung Video New Kodiaq New Tiguan Envia Find a vehicle Services Find garage Our vehicles Find and buy your car now directly online. #################### File: amag-ch-28917.txt Page: 1 Context: Find and buy your car now directly online. All brands VW Audi SEAT, CUPRA CUPRA Å koda VW Commercial Vehicles All brands Brand All models All models Model All Sedan Station wagon Convertible Coupé Van/minibus SUV/off-road vehicle Pickup Commercial vehicle/camper All Construction type All prices Until CHF 1'000 Until CHF 2'000 Until CHF 3'000 Until CHF 4'000 Until CHF 5'000 Until CHF 7'500 Until CHF 10'000 Until CHF 12'500 Until CHF 15'000 Until CHF 17'500 Until CHF 20'000 Until CHF 22'500 Until CHF 25'000 Until CHF 30'000 Until CHF 35'000 Until CHF 40'000 Until CHF 45'000 Until CHF 50'000 Until CHF 60'000 Until CHF 70'000 Until CHF 80'000 Until CHF 90'000 Until CHF 100'000 Until CHF 150'000 Until CHF 200'000 Until CHF 300'000 All prices Price until Find vehicles AMAG AMAG NEWS CUPRA PROMOTION The new CUPRA Formentor VZ e-HYBRID from CHF 450.–/month Pure passion Discover now SEAT PROMOTION The SEAT Ibiza Sensacion from CHF 250.– per month with no down payment Experience pure driving pleasure Discover now DYNAMIC. STIRRING. AMPLE. The Audi A1 Sportback from CHF 239.- per month Discover now ONLY FOR A SHORT TIME Discover our exclusive online deals Profit now Show more WELCOME TO AMAG From purchase via service to sale of your car – at AMAG you will find what you’re looking for Your dream car from AMAG 1 / 3 Buy or lease a car #################### File: amag-ch-28917.txt Page: 1 Context: Find what you’re looking for here. Discover all the offers from your AMAG! Find out more AMAG car subscription Get your dream car for a flat price per month - everything except fuel included. Find out more Sell a car Make room for new dreams. We buy your car. Find out more Our services for you 1 / 3 Your online appointment Without detours directly online on the desired date at an AMAG garage of your choice. Arrange an appointment Top garage services Quality and speed: our service and workshop staff are here for you. Find out more Help in case of damage Whether breakdown or hail damage. We are here for you 24/7. Find out more SERVICES Our most requested services The best service brings highest safety and comfort. How can we be of further assistance? Tyres and wheels Summer tyre change Winter tyre change Complete wheels All-season tyres About the service Air conditioning service Cleaning Fluid check Functional check About the service Car service / maintenance Mobility guarantee Original spare parts Maintenance of the warranty About the service Arrange an appointment I was able to easily and conveniently book my appointment online. Thank you for the amazing service! Regula S. Customer of AMAG Our AMAG pledge Full transparency Largest selection of vehicles Free test drive Buy a vehicle online with just a few clicks Fair trade-in price Greater safety 15 day right of exchange for used vehicles Quality check Minimum 12-month warranty Totalmobil! vehicle insurance Best service Breakdown assistance 24h Highest service quality Attractive financing options Individual insurance packages Turn your passion into a profession Do you have ambitious goals? Take your chance and find your dream job at AMAG. About the jobs AMAG – your car dealership at 90 locations and online #################### File: amag-ch-28917.txt Page: 1 Context: About the jobs AMAG – your car dealership at 90 locations and online Welcome to the biggest car dealership in Switzerland. As official Swiss dealership, we at AMAG offer you all the models of all the Volkswagen brands. At AMAG, you will find online and on site a huge range of new, stock and used vehicles from car brands like Volkswagen, Audi, SEAT, Å koda, CUPRA, VW Commercial Vehicles and Bentley. Of course, our experts also offer all the services related to the car after the purchase – be it a repair in the workshop or a consultation at the garage! Buy vehicles directly online To sell your car to AMAG All-round service for your car Find the AMAG garage of your choice Assistance & contact Contact Online appointment FAQ Online car purchase Corporate clients Newsletter Emergency Find a car & service Find a vehicle Services Find garage Car subscription Clyde Leasing Europcar Carsharing Company About us AMAG Group Sustainability Jobs & careers Press Our brands AMAG App Get connected with AMAG © 2024 AMAG Automobil und Motoren AG Privacy policy Legal notice Impressum Terms and conditions Cookie policy Jobs We use cookies to optimise the experience on our website. This includes the personalisation of content and ads, offering social networking features and traffic analysis. Such cookies include targeted social media cookies and cookies for advanced analysis. For more information, please see our information note on the cookie page. By clicking “Accept” you agree to our use of cookies. To change the types of cookies we use, please click on “Cookie settings”. Further information on data protection can be found here. Cookies Settings Reject all Accept all #################### File: amag-ch-28917.txt Page: 1 Context: ELECTROMOBILITY switch now AMAG GROUP Mobility, Sustainability & Future NO. 1 CAR DEALER IN SWITZERLAND with 90 locations Find a vehicle Services Find garage Jobs My garage EN Online-Leasing Discover our exclusive online leasing deals Profit now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. New CUPRA Formentor Discover now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. The new Audi Q6 e-tron from CHF 570.–/month* Discover now Full charge of rE-volution from a single source Discover now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. Fast help in the event of damage Report a damage online now The new Å koda Kodiaq Test drive now There is so much to discover! This will display external content. Click here to accept our cookie policy in order to view the content. The new Tiguan Discover now Envia – on the road at home with the camper from AMAG Take a closer look! New Formentor Q6 e-tron 360 Grad Lösungen Schadenmeldung Video New Kodiaq New Tiguan Envia Find a vehicle Services Find garage Our vehicles Find and buy your car now directly online. #################### File: amag-ch-28917.txt Page: 1 Context: Find and buy your car now directly online. All brands VW Audi SEAT, CUPRA CUPRA Å koda VW Commercial Vehicles All brands Brand All models All models Model All Sedan Station wagon Convertible Coupé Van/minibus SUV/off-road vehicle Pickup Commercial vehicle/camper All Construction type All prices Until CHF 1'000 Until CHF 2'000 Until CHF 3'000 Until CHF 4'000 Until CHF 5'000 Until CHF 7'500 Until CHF 10'000 Until CHF 12'500 Until CHF 15'000 Until CHF 17'500 Until CHF 20'000 Until CHF 22'500 Until CHF 25'000 Until CHF 30'000 Until CHF 35'000 Until CHF 40'000 Until CHF 45'000 Until CHF 50'000 Until CHF 60'000 Until CHF 70'000 Until CHF 80'000 Until CHF 90'000 Until CHF 100'000 Until CHF 150'000 Until CHF 200'000 Until CHF 300'000 All prices Price until Find vehicles AMAG AMAG NEWS CUPRA PROMOTION The new CUPRA Formentor VZ e-HYBRID from CHF 450.–/month Pure passion Discover now SEAT PROMOTION The SEAT Ibiza Sensacion from CHF 250.– per month with no down payment Experience pure driving pleasure Discover now DYNAMIC. STIRRING. AMPLE. The Audi A1 Sportback from CHF 239.- per month Discover now ONLY FOR A SHORT TIME Discover our exclusive online deals Profit now Show more WELCOME TO AMAG From purchase via service to sale of your car – at AMAG you will find what you’re looking for Your dream car from AMAG 1 / 3 Buy or lease a car #################### File: amag-ch-28917.txt Page: 1 Context: Find what you’re looking for here. Discover all the offers from your AMAG! Find out more AMAG car subscription Get your dream car for a flat price per month - everything except fuel included. Find out more Sell a car Make room for new dreams. We buy your car. Find out more Our services for you 1 / 3 Your online appointment Without detours directly online on the desired date at an AMAG garage of your choice. Arrange an appointment Top garage services Quality and speed: our service and workshop staff are here for you. Find out more Help in case of damage Whether breakdown or hail damage. We are here for you 24/7. Find out more SERVICES Our most requested services The best service brings highest safety and comfort. How can we be of further assistance? Tyres and wheels Summer tyre change Winter tyre change Complete wheels All-season tyres About the service Air conditioning service Cleaning Fluid check Functional check About the service Car service / maintenance Mobility guarantee Original spare parts Maintenance of the warranty About the service Arrange an appointment I was able to easily and conveniently book my appointment online. Thank you for the amazing service! Regula S. Customer of AMAG Our AMAG pledge Full transparency Largest selection of vehicles Free test drive Buy a vehicle online with just a few clicks Fair trade-in price Greater safety 15 day right of exchange for used vehicles Quality check Minimum 12-month warranty Totalmobil! vehicle insurance Best service Breakdown assistance 24h Highest service quality Attractive financing options Individual insurance packages Turn your passion into a profession Do you have ambitious goals? Take your chance and find your dream job at AMAG. About the jobs AMAG – your car dealership at 90 locations and online #################### File: amag-ch-28917.txt Page: 1 Context: About the jobs AMAG – your car dealership at 90 locations and online Welcome to the biggest car dealership in Switzerland. As official Swiss dealership, we at AMAG offer you all the models of all the Volkswagen brands. At AMAG, you will find online and on site a huge range of new, stock and used vehicles from car brands like Volkswagen, Audi, SEAT, Å koda, CUPRA, VW Commercial Vehicles and Bentley. Of course, our experts also offer all the services related to the car after the purchase – be it a repair in the workshop or a consultation at the garage! Buy vehicles directly online To sell your car to AMAG All-round service for your car Find the AMAG garage of your choice Assistance & contact Contact Online appointment FAQ Online car purchase Corporate clients Newsletter Emergency Find a car & service Find a vehicle Services Find garage Car subscription Clyde Leasing Europcar Carsharing Company About us AMAG Group Sustainability Jobs & careers Press Our brands AMAG App Get connected with AMAG © 2024 AMAG Automobil und Motoren AG Privacy policy Legal notice Impressum Terms and conditions Cookie policy Jobs We use cookies to optimise the experience on our website. This includes the personalisation of content and ads, offering social networking features and traffic analysis. Such cookies include targeted social media cookies and cookies for advanced analysis. For more information, please see our information note on the cookie page. By clicking “Accept” you agree to our use of cookies. To change the types of cookies we use, please click on “Cookie settings”. Further information on data protection can be found here. Cookies Settings Reject all Accept all #################### File: amag-ch-de-28918.txt Page: 1 Context: SCHNELL UND ONLINE Wir kaufen Ihr Auto AMAG GROUP Mobilität, Nachhaltigkeit & Zukunft NR. 1 IN DER SCHWEIZ mit 90 Standorten Auto finden Service Garage suchen Jobs Meine Garage DE Online-Leasing Entdecken Sie unsere exklusiven Online Leasing-Deals Jetzt entdecken Der neue Å koda Kodiaq mit CHF 5800.– Sparvorteil Jetzt entdecken. Der neue Audi Q6 e-tron Jetzt entdecken Elektromobilität zum Fixpreis: Alles inklusive, optional sogar Strom Clyde – das E-Auto-Abo der AMAG Der neue Tiguan Jetzt entdecken Envia – unterwegs daheim mit dem Camper von AMAG Jetzt entdecken E-Power aus einer Hand – von Photovoltaik bis E-Auto Entdecken Sie unsere Produkte Schnelle Hilfe im Schadensfall Jetzt Schaden online melden New Kodiaq Q6 e-tron Clyde New Tiguan Envia 360 Grad Lösungen Schaden Auto finden Service Garage suchen Starten Sie Ihre Occasionen und Neuwagen Suche! Finden Sie hier Occasionen und Neuwagen nach Ihren Wünschen. #################### File: amag-ch-de-28918.txt Page: 1 Context: Finden Sie hier Occasionen und Neuwagen nach Ihren Wünschen. Alle Marken VW Audi SEAT CUPRA Å koda VW Nutzfahrzeuge Alle Marken Marke Alle Modelle Alle Modelle Modell Alle Preise Bis CHF 1'000 Bis CHF 2'000 Bis CHF 3'000 Bis CHF 4'000 Bis CHF 5'000 Bis CHF 7'500 Bis CHF 10'000 Bis CHF 12'500 Bis CHF 15'000 Bis CHF 17'500 Bis CHF 20'000 Bis CHF 22'500 Bis CHF 25'000 Bis CHF 30'000 Bis CHF 35'000 Bis CHF 40'000 Bis CHF 45'000 Bis CHF 50'000 Bis CHF 60'000 Bis CHF 70'000 Bis CHF 80'000 Bis CHF 90'000 Bis CHF 100'000 Bis CHF 150'000 Bis CHF 200'000 Bis CHF 300'000 Alle Preise Preis bis Auto finden AMAG NEWS NEWS und ANGEBOTE DAS E-AUTO-ABO DER AMAG Clyde bietet E-Mobilität zum Fixpreis: alles inklusive, Strom optional Günstig, flexibel, einfach. Jetzt entdecken NACHHALTIG UNTERWEGS E-Power aus einer Hand – von Photovoltaik bis E-Auto Mehr erfahren BEREIT FÜR CAMPER-FERIEN? Jetzt online Camper mieten In wenigen Klicks zum Traumcamper Jetzt entdecken FRANZ IST AMAG Die AMAG übernimmt vier Standorte der Franz AG Der Name ändert, das Team und die Qualität bleiben. #################### File: amag-ch-de-28918.txt Page: 1 Context: Der Name ändert, das Team und die Qualität bleiben. Mehr erfahren Mehr anzeigen AKTUELLES Mobil in die Zukunft: News & Aktuelles Neuigkeiten und Trends der AMAG Group rund um das Thema Mobilität, Nachhaltigkeit und Zukunft. 04.04.2024 Bastian Baker wird neuer AMAG Ambassador Mehr erfahren 13.03.2024 AMAG bleibt Official Car Partner von YB Mehr erfahren 04.03.2024 Å koda verleiht AMAG Chur den Titel «Best Dealer 2023» Mehr erfahren Weitere Beiträge anzeigen UNSERE SERVICES Die gefragtesten AMAG Serviceleistungen Mit bestem Service kommt auch höchste Sicherheit. Unsere Fachleute kümmern sich persönlich um Ihr Fahrzeug und sorgen mit viel Erfahrung dafür, dass alles so läuft, wie es laufen soll. Räder und Reifen Sommerreifenwechsel Winterreifenwechsel Kompletträder Ganzjahresreifen Zum Service Klimaservice Reinigung Flüssigkeitskontrolle Pollenfilterkontrolle Zum Service Autoservice / Unterhalt Funktionsprüfung Ölwechsel Filteraustausch Teilecheck Zum Service Termin vereinbaren WILLKOMMEN BEI DER AMAG Vom Kauf über den Service bis zum Verkauf Ihres Autos – bei der AMAG finden Sie, was Sie suchen Ihr Traumauto von der AMAG 1 / 3 Auto kaufen oder leasen Hier finden Sie, was Sie suchen. Entdecken Sie alle Angebote von Ihrer AMAG. Mehr erfahren AMAG Auto-Abo Ihr Wunschauto zum monatlichen Fixpreis - ausser Tanken ist alles inklusive. Mehr erfahren Auto verkaufen Machen Sie Platz für neue Träume. Wir kaufen Ihr Auto. #################### File: amag-ch-de-28918.txt Page: 1 Context: Machen Sie Platz für neue Träume. Wir kaufen Ihr Auto. Mehr erfahren Unsere Services für Sie 1 / 3 Ihr Online-Termin Ohne Umwege direkt online zum Wunschtermin in einer AMAG Garage Ihrer Wahl. Termin vereinbaren Top-Services Qualität und Schnelligkeit: Unser Service- und Werkstattpersonal ist für Sie da. Mehr erfahren Hilfe im Schadensfall Ob Panne oder Hagelschaden: Wir sind 24 Stunden für Sie da. Mehr erfahren Wir bewegen und begeistern Menschen. Einfach. Nachhaltig. Voraus. Ich konnte meinen Termin einfach und bequem online buchen. Danke für den super Service! Regula S. Kundin bei AMAG Unser AMAG Versprechen Volle Transparenz Grösste Fahrzeugauswahl schweizweit Kostenlose Probefahrt Mit wenigen Klicks Fahrzeug online kaufen Fairer Eintauschpreis Mehr Sicherheit 15 Tage Umtauschrecht bei Occasionen Umfassender Qualitätscheck Mindestens 12 Monate Garantie Mobilitätsversicherung Totalmobil! Bester Service 24h Pannenhilfe  Höchste Servicequalität Attraktive Finanzierung Individuelle Versicherungen  Machen Sie Ihre Leidenschaft zum Beruf Sie haben grosse Ziele? Nutzen Sie Ihre Chance, und finden Sie Ihren Traumjob bei der AMAG. Zu den Jobs AMAG – Ihr Autohändler an 90 Standorten und online #################### File: amag-ch-de-28918.txt Page: 1 Context: Willkommen beim grössten Autohändler der Schweiz. Wir bei der AMAG bieten Ihnen als offizieller Schweizer Händler sämtliche Modelle aller Volkswagen Marken an. Bei der AMAG finden Sie online und vor Ort eine riesige Auswahl an Neuwagen, Lagerfahrzeugen und Occasionen von Automarken wie Volkswagen, Audi, SEAT, Å koda, CUPRA, VW Nutzfahrzeuge und Bentley. Natürlich bieten unsere Experten auch nach dem Kauf alle Services rund um das Auto an – sei es eine Reparatur in der Werkstatt oder eine Beratung in der Garage. Auto direkt online kaufen So verkaufen Sie Ihr Auto an die AMAG Rundumservice für Ihr Auto So finden Sie die AMAG Garage Ihrer Wahl Hilfe & Kontakt Kontakt Online-Termin FAQ Online-Autokauf Firmenkunden Newsletter Notfall Auto finden & Service Auto finden Service Garage suchen Leasing Auto-Abo Clyde Europcar Carsharing Parking Unternehmen Über uns AMAG Group Nachhaltigkeit Jobs & Karriere Presse Unsere Marken AMAG App Get connected with AMAG © 2024 AMAG Automobil und Motoren AG Datenschutzerklärung Rechtliche Hinweise Rechtliche Hinweise Online-Chat Cookie-Richtlinie Impressum AGB Jobs Der Schutz Ihrer Privatsphäre ist uns wichtig. Wir nutzen Cookies, um Ihr Erlebnis auf unserer Webseite zu optimieren und unsere Kommunikation mit Ihnen zu verbessern. Die Arten von Cookies, die wir einsetzen, werden unter «Cookie-Einstellungen» beschrieben. Wir berücksichtigen hierbei Ihre Präferenzen und verarbeiten Daten für Marketing, Analytics und Personalisierung nur, wenn Sie uns Ihre Einwilligung geben. Weitere Informationen zum Datenschutz finden Sie hier. Cookie-Einstellungen Alle ablehnen Alle erlauben #################### File: amag-ch-de-28918.txt Page: 1 Context: SCHNELL UND ONLINE Wir kaufen Ihr Auto AMAG GROUP Mobilität, Nachhaltigkeit & Zukunft NR. 1 IN DER SCHWEIZ mit 90 Standorten Auto finden Service Garage suchen Jobs Meine Garage DE Online-Leasing Entdecken Sie unsere exklusiven Online Leasing-Deals Jetzt entdecken Der neue Å koda Kodiaq mit CHF 5800.– Sparvorteil Jetzt entdecken. Der neue Audi Q6 e-tron Jetzt entdecken Elektromobilität zum Fixpreis: Alles inklusive, optional sogar Strom Clyde – das E-Auto-Abo der AMAG Der neue Tiguan Jetzt entdecken Envia – unterwegs daheim mit dem Camper von AMAG Jetzt entdecken E-Power aus einer Hand – von Photovoltaik bis E-Auto Entdecken Sie unsere Produkte Schnelle Hilfe im Schadensfall Jetzt Schaden online melden New Kodiaq Q6 e-tron Clyde New Tiguan Envia 360 Grad Lösungen Schaden Auto finden Service Garage suchen Starten Sie Ihre Occasionen und Neuwagen Suche! Finden Sie hier Occasionen und Neuwagen nach Ihren Wünschen. #################### File: amag-ch-de-28918.txt Page: 1 Context: Finden Sie hier Occasionen und Neuwagen nach Ihren Wünschen. Alle Marken VW Audi SEAT CUPRA Å koda VW Nutzfahrzeuge Alle Marken Marke Alle Modelle Alle Modelle Modell Alle Preise Bis CHF 1'000 Bis CHF 2'000 Bis CHF 3'000 Bis CHF 4'000 Bis CHF 5'000 Bis CHF 7'500 Bis CHF 10'000 Bis CHF 12'500 Bis CHF 15'000 Bis CHF 17'500 Bis CHF 20'000 Bis CHF 22'500 Bis CHF 25'000 Bis CHF 30'000 Bis CHF 35'000 Bis CHF 40'000 Bis CHF 45'000 Bis CHF 50'000 Bis CHF 60'000 Bis CHF 70'000 Bis CHF 80'000 Bis CHF 90'000 Bis CHF 100'000 Bis CHF 150'000 Bis CHF 200'000 Bis CHF 300'000 Alle Preise Preis bis Auto finden AMAG NEWS NEWS und ANGEBOTE DAS E-AUTO-ABO DER AMAG Clyde bietet E-Mobilität zum Fixpreis: alles inklusive, Strom optional Günstig, flexibel, einfach. Jetzt entdecken NACHHALTIG UNTERWEGS E-Power aus einer Hand – von Photovoltaik bis E-Auto Mehr erfahren BEREIT FÜR CAMPER-FERIEN? Jetzt online Camper mieten In wenigen Klicks zum Traumcamper Jetzt entdecken FRANZ IST AMAG Die AMAG übernimmt vier Standorte der Franz AG Der Name ändert, das Team und die Qualität bleiben. #################### File: amag-ch-de-28918.txt Page: 1 Context: Der Name ändert, das Team und die Qualität bleiben. Mehr erfahren Mehr anzeigen AKTUELLES Mobil in die Zukunft: News & Aktuelles Neuigkeiten und Trends der AMAG Group rund um das Thema Mobilität, Nachhaltigkeit und Zukunft. 04.04.2024 Bastian Baker wird neuer AMAG Ambassador Mehr erfahren 13.03.2024 AMAG bleibt Official Car Partner von YB Mehr erfahren 04.03.2024 Å koda verleiht AMAG Chur den Titel «Best Dealer 2023» Mehr erfahren Weitere Beiträge anzeigen UNSERE SERVICES Die gefragtesten AMAG Serviceleistungen Mit bestem Service kommt auch höchste Sicherheit. Unsere Fachleute kümmern sich persönlich um Ihr Fahrzeug und sorgen mit viel Erfahrung dafür, dass alles so läuft, wie es laufen soll. Räder und Reifen Sommerreifenwechsel Winterreifenwechsel Kompletträder Ganzjahresreifen Zum Service Klimaservice Reinigung Flüssigkeitskontrolle Pollenfilterkontrolle Zum Service Autoservice / Unterhalt Funktionsprüfung Ölwechsel Filteraustausch Teilecheck Zum Service Termin vereinbaren WILLKOMMEN BEI DER AMAG Vom Kauf über den Service bis zum Verkauf Ihres Autos – bei der AMAG finden Sie, was Sie suchen Ihr Traumauto von der AMAG 1 / 3 Auto kaufen oder leasen Hier finden Sie, was Sie suchen. Entdecken Sie alle Angebote von Ihrer AMAG. Mehr erfahren AMAG Auto-Abo Ihr Wunschauto zum monatlichen Fixpreis - ausser Tanken ist alles inklusive. Mehr erfahren Auto verkaufen Machen Sie Platz für neue Träume. Wir kaufen Ihr Auto. #################### File: amag-ch-de-28918.txt Page: 1 Context: Machen Sie Platz für neue Träume. Wir kaufen Ihr Auto. Mehr erfahren Unsere Services für Sie 1 / 3 Ihr Online-Termin Ohne Umwege direkt online zum Wunschtermin in einer AMAG Garage Ihrer Wahl. Termin vereinbaren Top-Services Qualität und Schnelligkeit: Unser Service- und Werkstattpersonal ist für Sie da. Mehr erfahren Hilfe im Schadensfall Ob Panne oder Hagelschaden: Wir sind 24 Stunden für Sie da. Mehr erfahren Wir bewegen und begeistern Menschen. Einfach. Nachhaltig. Voraus. Ich konnte meinen Termin einfach und bequem online buchen. Danke für den super Service! Regula S. Kundin bei AMAG Unser AMAG Versprechen Volle Transparenz Grösste Fahrzeugauswahl schweizweit Kostenlose Probefahrt Mit wenigen Klicks Fahrzeug online kaufen Fairer Eintauschpreis Mehr Sicherheit 15 Tage Umtauschrecht bei Occasionen Umfassender Qualitätscheck Mindestens 12 Monate Garantie Mobilitätsversicherung Totalmobil! Bester Service 24h Pannenhilfe  Höchste Servicequalität Attraktive Finanzierung Individuelle Versicherungen  Machen Sie Ihre Leidenschaft zum Beruf Sie haben grosse Ziele? Nutzen Sie Ihre Chance, und finden Sie Ihren Traumjob bei der AMAG. Zu den Jobs AMAG – Ihr Autohändler an 90 Standorten und online #################### File: amag-ch-de-28918.txt Page: 1 Context: Willkommen beim grössten Autohändler der Schweiz. Wir bei der AMAG bieten Ihnen als offizieller Schweizer Händler sämtliche Modelle aller Volkswagen Marken an. Bei der AMAG finden Sie online und vor Ort eine riesige Auswahl an Neuwagen, Lagerfahrzeugen und Occasionen von Automarken wie Volkswagen, Audi, SEAT, Å koda, CUPRA, VW Nutzfahrzeuge und Bentley. Natürlich bieten unsere Experten auch nach dem Kauf alle Services rund um das Auto an – sei es eine Reparatur in der Werkstatt oder eine Beratung in der Garage. Auto direkt online kaufen So verkaufen Sie Ihr Auto an die AMAG Rundumservice für Ihr Auto So finden Sie die AMAG Garage Ihrer Wahl Hilfe & Kontakt Kontakt Online-Termin FAQ Online-Autokauf Firmenkunden Newsletter Notfall Auto finden & Service Auto finden Service Garage suchen Leasing Auto-Abo Clyde Europcar Carsharing Parking Unternehmen Über uns AMAG Group Nachhaltigkeit Jobs & Karriere Presse Unsere Marken AMAG App Get connected with AMAG © 2024 AMAG Automobil und Motoren AG Datenschutzerklärung Rechtliche Hinweise Rechtliche Hinweise Online-Chat Cookie-Richtlinie Impressum AGB Jobs Der Schutz Ihrer Privatsphäre ist uns wichtig. Wir nutzen Cookies, um Ihr Erlebnis auf unserer Webseite zu optimieren und unsere Kommunikation mit Ihnen zu verbessern. Die Arten von Cookies, die wir einsetzen, werden unter «Cookie-Einstellungen» beschrieben. Wir berücksichtigen hierbei Ihre Präferenzen und verarbeiten Daten für Marketing, Analytics und Personalisierung nur, wenn Sie uns Ihre Einwilligung geben. Weitere Informationen zum Datenschutz finden Sie hier. Cookie-Einstellungen Alle ablehnen Alle erlauben #################### File: amag-ch-de-28918.txt Page: 1 Context: SCHNELL UND ONLINE Wir kaufen Ihr Auto AMAG GROUP Mobilität, Nachhaltigkeit & Zukunft NR. 1 IN DER SCHWEIZ mit 90 Standorten Auto finden Service Garage suchen Jobs Meine Garage DE Online-Leasing Entdecken Sie unsere exklusiven Online Leasing-Deals Jetzt entdecken Der neue Å koda Kodiaq mit CHF 5800.– Sparvorteil Jetzt entdecken. Der neue Audi Q6 e-tron Jetzt entdecken Elektromobilität zum Fixpreis: Alles inklusive, optional sogar Strom Clyde – das E-Auto-Abo der AMAG Der neue Tiguan Jetzt entdecken Envia – unterwegs daheim mit dem Camper von AMAG Jetzt entdecken E-Power aus einer Hand – von Photovoltaik bis E-Auto Entdecken Sie unsere Produkte Schnelle Hilfe im Schadensfall Jetzt Schaden online melden New Kodiaq Q6 e-tron Clyde New Tiguan Envia 360 Grad Lösungen Schaden Auto finden Service Garage suchen Starten Sie Ihre Occasionen und Neuwagen Suche! Finden Sie hier Occasionen und Neuwagen nach Ihren Wünschen. #################### File: amag-ch-de-28918.txt Page: 1 Context: Finden Sie hier Occasionen und Neuwagen nach Ihren Wünschen. Alle Marken VW Audi SEAT CUPRA Å koda VW Nutzfahrzeuge Alle Marken Marke Alle Modelle Alle Modelle Modell Alle Preise Bis CHF 1'000 Bis CHF 2'000 Bis CHF 3'000 Bis CHF 4'000 Bis CHF 5'000 Bis CHF 7'500 Bis CHF 10'000 Bis CHF 12'500 Bis CHF 15'000 Bis CHF 17'500 Bis CHF 20'000 Bis CHF 22'500 Bis CHF 25'000 Bis CHF 30'000 Bis CHF 35'000 Bis CHF 40'000 Bis CHF 45'000 Bis CHF 50'000 Bis CHF 60'000 Bis CHF 70'000 Bis CHF 80'000 Bis CHF 90'000 Bis CHF 100'000 Bis CHF 150'000 Bis CHF 200'000 Bis CHF 300'000 Alle Preise Preis bis Auto finden AMAG NEWS NEWS und ANGEBOTE DAS E-AUTO-ABO DER AMAG Clyde bietet E-Mobilität zum Fixpreis: alles inklusive, Strom optional Günstig, flexibel, einfach. Jetzt entdecken NACHHALTIG UNTERWEGS E-Power aus einer Hand – von Photovoltaik bis E-Auto Mehr erfahren BEREIT FÜR CAMPER-FERIEN? Jetzt online Camper mieten In wenigen Klicks zum Traumcamper Jetzt entdecken FRANZ IST AMAG Die AMAG übernimmt vier Standorte der Franz AG Der Name ändert, das Team und die Qualität bleiben. #################### File: amag-ch-de-28918.txt Page: 1 Context: Der Name ändert, das Team und die Qualität bleiben. Mehr erfahren Mehr anzeigen AKTUELLES Mobil in die Zukunft: News & Aktuelles Neuigkeiten und Trends der AMAG Group rund um das Thema Mobilität, Nachhaltigkeit und Zukunft. 04.04.2024 Bastian Baker wird neuer AMAG Ambassador Mehr erfahren 13.03.2024 AMAG bleibt Official Car Partner von YB Mehr erfahren 04.03.2024 Å koda verleiht AMAG Chur den Titel «Best Dealer 2023» Mehr erfahren Weitere Beiträge anzeigen UNSERE SERVICES Die gefragtesten AMAG Serviceleistungen Mit bestem Service kommt auch höchste Sicherheit. Unsere Fachleute kümmern sich persönlich um Ihr Fahrzeug und sorgen mit viel Erfahrung dafür, dass alles so läuft, wie es laufen soll. Räder und Reifen Sommerreifenwechsel Winterreifenwechsel Kompletträder Ganzjahresreifen Zum Service Klimaservice Reinigung Flüssigkeitskontrolle Pollenfilterkontrolle Zum Service Autoservice / Unterhalt Funktionsprüfung Ölwechsel Filteraustausch Teilecheck Zum Service Termin vereinbaren WILLKOMMEN BEI DER AMAG Vom Kauf über den Service bis zum Verkauf Ihres Autos – bei der AMAG finden Sie, was Sie suchen Ihr Traumauto von der AMAG 1 / 3 Auto kaufen oder leasen Hier finden Sie, was Sie suchen. Entdecken Sie alle Angebote von Ihrer AMAG. Mehr erfahren AMAG Auto-Abo Ihr Wunschauto zum monatlichen Fixpreis - ausser Tanken ist alles inklusive. Mehr erfahren Auto verkaufen Machen Sie Platz für neue Träume. Wir kaufen Ihr Auto. #################### File: amag-ch-de-28918.txt Page: 1 Context: Machen Sie Platz für neue Träume. Wir kaufen Ihr Auto. Mehr erfahren Unsere Services für Sie 1 / 3 Ihr Online-Termin Ohne Umwege direkt online zum Wunschtermin in einer AMAG Garage Ihrer Wahl. Termin vereinbaren Top-Services Qualität und Schnelligkeit: Unser Service- und Werkstattpersonal ist für Sie da. Mehr erfahren Hilfe im Schadensfall Ob Panne oder Hagelschaden: Wir sind 24 Stunden für Sie da. Mehr erfahren Wir bewegen und begeistern Menschen. Einfach. Nachhaltig. Voraus. Ich konnte meinen Termin einfach und bequem online buchen. Danke für den super Service! Regula S. Kundin bei AMAG Unser AMAG Versprechen Volle Transparenz Grösste Fahrzeugauswahl schweizweit Kostenlose Probefahrt Mit wenigen Klicks Fahrzeug online kaufen Fairer Eintauschpreis Mehr Sicherheit 15 Tage Umtauschrecht bei Occasionen Umfassender Qualitätscheck Mindestens 12 Monate Garantie Mobilitätsversicherung Totalmobil! Bester Service 24h Pannenhilfe  Höchste Servicequalität Attraktive Finanzierung Individuelle Versicherungen  Machen Sie Ihre Leidenschaft zum Beruf Sie haben grosse Ziele? Nutzen Sie Ihre Chance, und finden Sie Ihren Traumjob bei der AMAG. Zu den Jobs AMAG – Ihr Autohändler an 90 Standorten und online #################### File: amag-ch-de-28918.txt Page: 1 Context: Willkommen beim grössten Autohändler der Schweiz. Wir bei der AMAG bieten Ihnen als offizieller Schweizer Händler sämtliche Modelle aller Volkswagen Marken an. Bei der AMAG finden Sie online und vor Ort eine riesige Auswahl an Neuwagen, Lagerfahrzeugen und Occasionen von Automarken wie Volkswagen, Audi, SEAT, Å koda, CUPRA, VW Nutzfahrzeuge und Bentley. Natürlich bieten unsere Experten auch nach dem Kauf alle Services rund um das Auto an – sei es eine Reparatur in der Werkstatt oder eine Beratung in der Garage. Auto direkt online kaufen So verkaufen Sie Ihr Auto an die AMAG Rundumservice für Ihr Auto So finden Sie die AMAG Garage Ihrer Wahl Hilfe & Kontakt Kontakt Online-Termin FAQ Online-Autokauf Firmenkunden Newsletter Notfall Auto finden & Service Auto finden Service Garage suchen Leasing Auto-Abo Clyde Europcar Carsharing Parking Unternehmen Über uns AMAG Group Nachhaltigkeit Jobs & Karriere Presse Unsere Marken AMAG App Get connected with AMAG © 2024 AMAG Automobil und Motoren AG Datenschutzerklärung Rechtliche Hinweise Rechtliche Hinweise Online-Chat Cookie-Richtlinie Impressum AGB Jobs Der Schutz Ihrer Privatsphäre ist uns wichtig. Wir nutzen Cookies, um Ihr Erlebnis auf unserer Webseite zu optimieren und unsere Kommunikation mit Ihnen zu verbessern. Die Arten von Cookies, die wir einsetzen, werden unter «Cookie-Einstellungen» beschrieben. Wir berücksichtigen hierbei Ihre Präferenzen und verarbeiten Daten für Marketing, Analytics und Personalisierung nur, wenn Sie uns Ihre Einwilligung geben. Weitere Informationen zum Datenschutz finden Sie hier. Cookie-Einstellungen Alle ablehnen Alle erlauben #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: SCHNELL UND ONLINE Wir kaufen Ihr Auto AMAG GROUP Mobilität, Nachhaltigkeit & Zukunft NR. 1 IN DER SCHWEIZ Mit 85 Standorten Auto finden Service Garage suchen Jobs Meine Garage DE Exklusiv bei Online-Leasing Entdecken Sie exklusive Online Leasing-Deals Jetzt online Leasing abschliessen Marke - - - AUDI CUPRA SEAT Å koda VW VW Nutzfahrzeuge - - - Alfa Romeo Bentley BMW Chevrolet Citroën Dacia Fiat Ford Honda Hyundai Jaguar Jeep Kia Land Rover Maserati Mazda Mercedes-Benz Micro MINI Mitsubishi Nissan Opel Peugeot Porsche Renault Smart Subaru Suzuki Toyota Volvo - - - Andere Modell SUCHE SPEICHERN Fahrzeugdaten 1 Ausstattung 0 PROMOTIONEN Exklusiv bei Online-Leasing Spezial Elektro Leasing Online-Deals Leasing ab CHF 249 NEUHEITEN Bald verfügbar INVERKEHRSETZUNG Jahr Alle Ab 2024 Ab 2023 Ab 2022 Ab 2021 Ab 2020 Ab 2019 Ab 2018 Ab 2017 Ab 2016 Ab 2015 Ab 2014 Ab 2013 Ab 2012 Ab 2011 Ab 2010 Ab 2009 Ab 2008 Ab 2007 Ab 2006 Ab 2005 PREIS (CHF) Kauf Leasing #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Kauf Leasing KAUFPREIS von Alle 3’000 4’000 5’000 7’500 10’000 12’500 15’000 17’500 20’000 22’500 25’000 30’000 35’000 40’000 45’000 50’000 60’000 70’000 80’000 90’000 100’000 125’000 150’000 175’000 200’000 bis Alle 3’000 4’000 5’000 7’500 10’000 12’500 15’000 17’500 20’000 22’500 25’000 30’000 35’000 40’000 45’000 50’000 60’000 70’000 80’000 90’000 100’000 125’000 150’000 175’000 200’000 STANDORT Alle KRAFTSTOFFART Benzin Diesel Hybrid Elektro Gas H2 ANTRIEB Front Heck Allrad GETRIEBE Automatik Schaltung FAHRZEUGART #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: GETRIEBE Automatik Schaltung FAHRZEUGART Neu-/Lagerfahrzeuge Occasionen Vorführwagen Elektrofahrzeuge Abo KILOMETERSTAND von Alle 1’000 5’000 10’000 20’000 30’000 40’000 50’000 60’000 70’000 80’000 90’000 100’000 110’000 120’000 130’000 140’000 150’000 bis Alle 1’000 5’000 10’000 20’000 30’000 40’000 50’000 60’000 70’000 80’000 90’000 100’000 110’000 120’000 130’000 140’000 150’000 LEISTUNG (PS) von Alle 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 bis Alle 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 KAROSSERIEVARIANTE Alle Limousine Kombi Cabriolet Coupé Van/Kleinbus SUV / Geländewagen Pickup Nutzfahrzeuge / Camper ANZAHL SITZE von Alle 1 2 3 4 5 6 7 8 bis Alle 2 3 4 5 6 7 8 9 #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: ANZAHL TÜREN von Alle 2 3 4 5 bis Alle 2 3 4 5 FARBE ( AUSSEN ) Alle anthrazit beige blau bordeaux braun gelb gold grau grün mehrfarbig orange pink rot schwarz silber türkis violett weiss FARBE ( INNEN ) Alle anthrazit beige blau braun bronze gelb gold grau grün mehrfarbig orange rot schwarz silber violett weiss REFERENZ-NUMMER ALLE FILTER (1) ZURÜCKSETZEN EXKLUSIV BEI ONLINE-LEASING Entdecken Sie exklusive Online Leasing-Deals Jetzt abschliessen 101 Fahrzeuge verfügbar 161 Exklusiv bei Online-Leasing: Profitieren Sie bei sämtlichen Occasionsfahrzeugen, die auf auto.amag.ch als Online Deal gekennzeichnet sind beim Abschluss eines Leasingvertrages über auto.amag.ch bis 30.09.2024 oder bis auf Widerruf von einem 3.99% Leasing. Berechnungsbeispiel mit Fahrzeugpreis CHF 44’310. Effektiver Jahreszins 4,06%, Laufzeit: 48 Mt. (15’000 km Jahr), Sonderzahlung: CHF 0.-, Leasingrate: CHF 612.– Mt., inkl. MwSt., exkl. obligatorischer Vollkaskoversicherung. Aktion nur gültig so lange Vorrat. Änderungen vorbehalten. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Finanzierung über AMAG Leasing AG. Jetzt online Leasing abschliessen Aktuell sind 101 Fahrzeuge für Sie verfügbar. #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Ihre Suchergebnisse ALLE FILTER ZURÜCKSETZEN Sortieren Nach Name Preis aufsteigend Preis absteigend Nach Kilometer Jahrgang neuste Jahrgang älteste in Aufbereitung EXKLUSIV BEI ONLINE-LEASING #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: VW Arteon Shooting Brake R-Line CHF 44’450.- Leasing ab CHF 403.- /Monat 31’200 km 05/2023 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW Passat Variant Elegance CHF 33’950.- Leasing ab CHF 304.- /Monat 41’500 km 12/2022 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING SEAT IBIZA FR CHF 23’700.- Leasing ab CHF 219.- /Monat 20’600 km 05/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING AUDI Q3 40 TFSI advanced CHF 30’900.- Leasing ab CHF 369.- /Monat 47’800 km 05/2019 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VWNF California 6.1 Ocean Liberty CHF 68’900.- Leasing ab CHF 651.- /Monat 15’000 km 01/2022 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING VWNF California 6.1 Beach Liberty CHF 65’900.- Leasing ab CHF 512.- /Monat 18’200 km 04/2023 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING Å koda SUPERB Sportline "Light" CHF 34’500.- Leasing ab CHF 306.- /Monat 55’000 km 06/2022 Diesel Automatik Abo EXKLUSIV BEI ONLINE-LEASING Å koda KAROQ ''Smile'' (netto) CHF 20’100.- #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: CHF 20’100.- Leasing ab CHF 224.- /Monat 88’660 km 04/2019 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING Å koda Kamiq Ambition CHF 27’430.- Leasing ab CHF 257.- /Monat 33’000 km 06/2023 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING AUDI RS 6 Avant CHF 94’900.- Leasing ab CHF 959.- /Monat 73’058 km 09/2020 Benzin MHEV Automatik EXKLUSIV BEI ONLINE-LEASING Å koda Octavia Style CHF 34’900.- Leasing ab CHF 292.- /Monat 9’000 km 09/2023 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW T-Roc Advance CHF 22’900.- Leasing ab CHF 294.- /Monat 43’846 km 08/2018 Benzin Schaltung EXKLUSIV BEI ONLINE-LEASING VW T-Cross Life CHF 21’900.- Leasing ab CHF 230.- /Monat 71’200 km 10/2020 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW Polo Style CHF 24’990.- Leasing ab CHF 255.- /Monat 21’200 km 07/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING AUDI TT Roadster CHF 26’770.- Jetzt Offerte einholen 82’900 km 08/2015 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Automatik EXKLUSIV BEI ONLINE-LEASING VW Tiguan Highline CHF 27’970.- Leasing ab CHF 308.- /Monat 68’115 km 09/2018 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW Tiguan Starter CHF 22’490.- Leasing ab CHF 214.- /Monat 48’500 km 12/2020 Benzin Schaltung Abo EXKLUSIV BEI ONLINE-LEASING VW Tiguan Elegance CHF 41’950.- Leasing ab CHF 344.- /Monat 24’500 km 07/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING Å koda Scala Ambition CHF 24’950.- Leasing ab CHF 226.- /Monat 24’900 km 03/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING VW Polo Life CHF 22’900.- Leasing ab CHF 218.- /Monat 16’600 km 07/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING Å koda Karoq SportLine CHF 41’900.- Leasing ab CHF 389.- /Monat 22’990 km 04/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING VWNF California 6.1 Ocean Liberty CHF 71’450.- Leasing ab CHF 552.- /Monat 11’900 km 06/2023 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING AUDI Q2 40 TFSI sport #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: AUDI Q2 40 TFSI sport CHF 33’400.- Leasing ab CHF 382.- /Monat 52’300 km 08/2020 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING AUDI Q5 55 TFSI e sport CHF 38’900.- Leasing ab CHF 450.- /Monat 69’600 km 09/2019 Hybrid Automatik Abo 24 Fahrzeuge pro Seite 48 Fahrzeuge pro Seite 72 Fahrzeuge pro Seite 96 Fahrzeuge pro Seite «12345» Exklusiv bei Online-Leasing: Profitieren Sie bei sämtlichen Occasionsfahrzeugen, die auf auto.amag.ch als Online Deal gekennzeichnet sind beim Abschluss eines Leasingvertrages über auto.amag.ch bis 30.09.2024 oder bis auf Widerruf von einem 3.99% Leasing. Berechnungsbeispiel mit Fahrzeugpreis CHF 44’310. Effektiver Jahreszins 4,06%, Laufzeit: 48 Mt. (15’000 km Jahr), Sonderzahlung: CHF 0.-, Leasingrate: CHF 612.– Mt., inkl. MwSt., exkl. obligatorischer Vollkaskoversicherung. Aktion nur gültig so lange Vorrat. Änderungen vorbehalten. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Finanzierung über AMAG Leasing AG. #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Spezial Elektro Leasing: 2.99% AMAG Basic PLUS für alle Occasion Elektrofahrzeugmodelle der VW-Konzernmarken. Gültig bei Abschluss eines AMAG Basic PLUS bis 30.09.2024 oder bis auf Widerruf auf sofort verfügbare Elektrofahrzeuge (Occasionen >1000km). Rechnungsbeispiel mit Kaufpreis: CHF 59’710.–. Effektiver Jahreszins: 3.03%, Laufzeit: 48 Monate (15‘000 km Jahr), Sonderzahlung 0%: CHF 0.–, Leasingrate: CHF 758.44.- Mt. exkl. obligatorische Vollkasko-Motorfahrzeugversicherung. AMAG Basic PLUS beinhaltet die Dienstleistungen Service, bestimmte Flüssigkeiten, Verschleiss und 3 Monate Garantieverlängerung geschenkt. 1.74% AMAG Advanced PLUS für alle Occasion Elektrofahrzeugmodelle der VW-Konzernmarken. Gültig bei Abschluss eines AMAG Advanced PLUS bis 30.09.2024 oder bis auf Widerruf auf sofort verfügbare Elektrofahrzeuge (Occasionen >1000km). Rechnungsbeispiel mit Kaufpreis: CHF 45’000.–. Effektiver Jahreszins: 2.01%, Laufzeit: 48 Monate (10‘000 km Jahr), Sonderzahlung 20%: CHF 9’000.–, Leasingrate: CHF 488.- Mt. exkl. obligatorische Vollkasko-Motorfahrzeugversicherung. AMAG Advanced PLUS beinhaltet die Dienstleistungen Service, bestimmte Flüssigkeiten, Reifenkontingent gemäss Laufzeit, Laufleistung sowie Räder- oder Reifenwechsel und 6 Monate Garantieverlängerung geschenkt. Vertragsabschlüsse #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Garantieverlängerung geschenkt. Vertragsabschlüsse über Occasionsfahrzeuge bis 30.06.2024 oder bis auf Widerruf. Das Fahrzeug darf nach Ablauf des Leasingvertrages nicht älter als 8 Jahre alt sein (Datum erste Inverkehrsetzung ist massgebend.) Der Kilometerstand darf nach Ablauf des Leasingvertrages nicht mehr als 180 000 km aufweisen. Finanzierung über AMAG Leasing AG. Nur bei teilnehmenden AMAG Retail Betrieben. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Änderungen vorbehalten. Solange Vorrat #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Leasing ab CHF 249: Berechnungsbeispiel Leasing: Barkaufpreis: CHF 35’999.–. Effektiver Jahreszins: 4.07 %, Laufzeit: 48 Monate (10’000 km Jahr), Sonderzahlung CHF 7’112.–, Leasingrate Fahrzeug: CHF 248.51 Mt. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Finanzierung über die AMAG Leasing AG. Gültig nur für Lagerfahrzeuge. Aktion gültig bis 31.08.2024. Bereits bestehende Leasinganträge können nicht rückwirkend angepasst werden. Das Leasing ist nicht kumulierbar mit Flottenkonditionen. Nur bei teilnehmenden AMAG Betrieben und nur solange Vorrat. Änderungen Hilfe & Kontakt Kontakt Online-Termin FAQ Online-Autokauf Firmenkunden Newsletter Notfall Auto finden & Service Auto finden Service Garage suchen Leasing Auto Abo Europcar Carsharing Parking Unternehmen Über uns AMAG Group Nachhaltigkeit Jobs & Karriere Presse Unsere Marken AMAG App Get connected with AMAG © 2024 AMAG Automobil und Motoren AG Datenschutzerklärung Rechtliche Hinweise Rechtliche Hinweise Online-Chat Cookie-Richtlinie Impressum AGB Jobs #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Der Schutz Ihrer Privatsphäre ist uns wichtig. Wir nutzen Cookies, um Ihr Erlebnis auf unserer Webseite zu optimieren und unsere Kommunikation mit Ihnen zu verbessern. Die Arten von Cookies, die wir einsetzen, werden unter «Cookie-Einstellungen» beschrieben. Wir berücksichtigen hierbei Ihre Präferenzen und verarbeiten Daten für Marketing, Analytics und Personalisierung nur, wenn Sie uns Ihre Einwilligung geben. Weitere Informationen zum Datenschutz finden Sie hier. Cookie-Einstellungen Alle ablehnen Alle erlauben #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: SCHNELL UND ONLINE Wir kaufen Ihr Auto AMAG GROUP Mobilität, Nachhaltigkeit & Zukunft NR. 1 IN DER SCHWEIZ Mit 85 Standorten Auto finden Service Garage suchen Jobs Meine Garage DE Exklusiv bei Online-Leasing Entdecken Sie exklusive Online Leasing-Deals Jetzt online Leasing abschliessen Marke - - - AUDI CUPRA SEAT Å koda VW VW Nutzfahrzeuge - - - Alfa Romeo Bentley BMW Chevrolet Citroën Dacia Fiat Ford Honda Hyundai Jaguar Jeep Kia Land Rover Maserati Mazda Mercedes-Benz Micro MINI Mitsubishi Nissan Opel Peugeot Porsche Renault Smart Subaru Suzuki Toyota Volvo - - - Andere Modell SUCHE SPEICHERN Fahrzeugdaten 1 Ausstattung 0 PROMOTIONEN Exklusiv bei Online-Leasing Spezial Elektro Leasing Online-Deals Leasing ab CHF 249 NEUHEITEN Bald verfügbar INVERKEHRSETZUNG Jahr Alle Ab 2024 Ab 2023 Ab 2022 Ab 2021 Ab 2020 Ab 2019 Ab 2018 Ab 2017 Ab 2016 Ab 2015 Ab 2014 Ab 2013 Ab 2012 Ab 2011 Ab 2010 Ab 2009 Ab 2008 Ab 2007 Ab 2006 Ab 2005 PREIS (CHF) Kauf Leasing #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Kauf Leasing KAUFPREIS von Alle 3’000 4’000 5’000 7’500 10’000 12’500 15’000 17’500 20’000 22’500 25’000 30’000 35’000 40’000 45’000 50’000 60’000 70’000 80’000 90’000 100’000 125’000 150’000 175’000 200’000 bis Alle 3’000 4’000 5’000 7’500 10’000 12’500 15’000 17’500 20’000 22’500 25’000 30’000 35’000 40’000 45’000 50’000 60’000 70’000 80’000 90’000 100’000 125’000 150’000 175’000 200’000 STANDORT Alle KRAFTSTOFFART Benzin Diesel Hybrid Elektro Gas H2 ANTRIEB Front Heck Allrad GETRIEBE Automatik Schaltung FAHRZEUGART #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: GETRIEBE Automatik Schaltung FAHRZEUGART Neu-/Lagerfahrzeuge Occasionen Vorführwagen Elektrofahrzeuge Abo KILOMETERSTAND von Alle 1’000 5’000 10’000 20’000 30’000 40’000 50’000 60’000 70’000 80’000 90’000 100’000 110’000 120’000 130’000 140’000 150’000 bis Alle 1’000 5’000 10’000 20’000 30’000 40’000 50’000 60’000 70’000 80’000 90’000 100’000 110’000 120’000 130’000 140’000 150’000 LEISTUNG (PS) von Alle 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 bis Alle 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 KAROSSERIEVARIANTE Alle Limousine Kombi Cabriolet Coupé Van/Kleinbus SUV / Geländewagen Pickup Nutzfahrzeuge / Camper ANZAHL SITZE von Alle 1 2 3 4 5 6 7 8 bis Alle 2 3 4 5 6 7 8 9 #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: ANZAHL TÜREN von Alle 2 3 4 5 bis Alle 2 3 4 5 FARBE ( AUSSEN ) Alle anthrazit beige blau bordeaux braun gelb gold grau grün mehrfarbig orange pink rot schwarz silber türkis violett weiss FARBE ( INNEN ) Alle anthrazit beige blau braun bronze gelb gold grau grün mehrfarbig orange rot schwarz silber violett weiss REFERENZ-NUMMER ALLE FILTER (1) ZURÜCKSETZEN EXKLUSIV BEI ONLINE-LEASING Entdecken Sie exklusive Online Leasing-Deals Jetzt abschliessen 101 Fahrzeuge verfügbar 161 Exklusiv bei Online-Leasing: Profitieren Sie bei sämtlichen Occasionsfahrzeugen, die auf auto.amag.ch als Online Deal gekennzeichnet sind beim Abschluss eines Leasingvertrages über auto.amag.ch bis 30.09.2024 oder bis auf Widerruf von einem 3.99% Leasing. Berechnungsbeispiel mit Fahrzeugpreis CHF 44’310. Effektiver Jahreszins 4,06%, Laufzeit: 48 Mt. (15’000 km Jahr), Sonderzahlung: CHF 0.-, Leasingrate: CHF 612.– Mt., inkl. MwSt., exkl. obligatorischer Vollkaskoversicherung. Aktion nur gültig so lange Vorrat. Änderungen vorbehalten. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Finanzierung über AMAG Leasing AG. Jetzt online Leasing abschliessen Aktuell sind 101 Fahrzeuge für Sie verfügbar. #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Ihre Suchergebnisse ALLE FILTER ZURÜCKSETZEN Sortieren Nach Name Preis aufsteigend Preis absteigend Nach Kilometer Jahrgang neuste Jahrgang älteste in Aufbereitung EXKLUSIV BEI ONLINE-LEASING #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: VW Arteon Shooting Brake R-Line CHF 44’450.- Leasing ab CHF 403.- /Monat 31’200 km 05/2023 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW Passat Variant Elegance CHF 33’950.- Leasing ab CHF 304.- /Monat 41’500 km 12/2022 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING SEAT IBIZA FR CHF 23’700.- Leasing ab CHF 219.- /Monat 20’600 km 05/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING AUDI Q3 40 TFSI advanced CHF 30’900.- Leasing ab CHF 369.- /Monat 47’800 km 05/2019 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VWNF California 6.1 Ocean Liberty CHF 68’900.- Leasing ab CHF 651.- /Monat 15’000 km 01/2022 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING VWNF California 6.1 Beach Liberty CHF 65’900.- Leasing ab CHF 512.- /Monat 18’200 km 04/2023 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING Å koda SUPERB Sportline "Light" CHF 34’500.- Leasing ab CHF 306.- /Monat 55’000 km 06/2022 Diesel Automatik Abo EXKLUSIV BEI ONLINE-LEASING Å koda KAROQ ''Smile'' (netto) CHF 20’100.- #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: CHF 20’100.- Leasing ab CHF 224.- /Monat 88’660 km 04/2019 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING Å koda Kamiq Ambition CHF 27’430.- Leasing ab CHF 257.- /Monat 33’000 km 06/2023 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING AUDI RS 6 Avant CHF 94’900.- Leasing ab CHF 959.- /Monat 73’058 km 09/2020 Benzin MHEV Automatik EXKLUSIV BEI ONLINE-LEASING Å koda Octavia Style CHF 34’900.- Leasing ab CHF 292.- /Monat 9’000 km 09/2023 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW T-Roc Advance CHF 22’900.- Leasing ab CHF 294.- /Monat 43’846 km 08/2018 Benzin Schaltung EXKLUSIV BEI ONLINE-LEASING VW T-Cross Life CHF 21’900.- Leasing ab CHF 230.- /Monat 71’200 km 10/2020 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW Polo Style CHF 24’990.- Leasing ab CHF 255.- /Monat 21’200 km 07/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING AUDI TT Roadster CHF 26’770.- Jetzt Offerte einholen 82’900 km 08/2015 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Automatik EXKLUSIV BEI ONLINE-LEASING VW Tiguan Highline CHF 27’970.- Leasing ab CHF 308.- /Monat 68’115 km 09/2018 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW Tiguan Starter CHF 22’490.- Leasing ab CHF 214.- /Monat 48’500 km 12/2020 Benzin Schaltung Abo EXKLUSIV BEI ONLINE-LEASING VW Tiguan Elegance CHF 41’950.- Leasing ab CHF 344.- /Monat 24’500 km 07/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING Å koda Scala Ambition CHF 24’950.- Leasing ab CHF 226.- /Monat 24’900 km 03/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING VW Polo Life CHF 22’900.- Leasing ab CHF 218.- /Monat 16’600 km 07/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING Å koda Karoq SportLine CHF 41’900.- Leasing ab CHF 389.- /Monat 22’990 km 04/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING VWNF California 6.1 Ocean Liberty CHF 71’450.- Leasing ab CHF 552.- /Monat 11’900 km 06/2023 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING AUDI Q2 40 TFSI sport #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: AUDI Q2 40 TFSI sport CHF 33’400.- Leasing ab CHF 382.- /Monat 52’300 km 08/2020 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING AUDI Q5 55 TFSI e sport CHF 38’900.- Leasing ab CHF 450.- /Monat 69’600 km 09/2019 Hybrid Automatik Abo 24 Fahrzeuge pro Seite 48 Fahrzeuge pro Seite 72 Fahrzeuge pro Seite 96 Fahrzeuge pro Seite «12345» Exklusiv bei Online-Leasing: Profitieren Sie bei sämtlichen Occasionsfahrzeugen, die auf auto.amag.ch als Online Deal gekennzeichnet sind beim Abschluss eines Leasingvertrages über auto.amag.ch bis 30.09.2024 oder bis auf Widerruf von einem 3.99% Leasing. Berechnungsbeispiel mit Fahrzeugpreis CHF 44’310. Effektiver Jahreszins 4,06%, Laufzeit: 48 Mt. (15’000 km Jahr), Sonderzahlung: CHF 0.-, Leasingrate: CHF 612.– Mt., inkl. MwSt., exkl. obligatorischer Vollkaskoversicherung. Aktion nur gültig so lange Vorrat. Änderungen vorbehalten. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Finanzierung über AMAG Leasing AG. #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Spezial Elektro Leasing: 2.99% AMAG Basic PLUS für alle Occasion Elektrofahrzeugmodelle der VW-Konzernmarken. Gültig bei Abschluss eines AMAG Basic PLUS bis 30.09.2024 oder bis auf Widerruf auf sofort verfügbare Elektrofahrzeuge (Occasionen >1000km). Rechnungsbeispiel mit Kaufpreis: CHF 59’710.–. Effektiver Jahreszins: 3.03%, Laufzeit: 48 Monate (15‘000 km Jahr), Sonderzahlung 0%: CHF 0.–, Leasingrate: CHF 758.44.- Mt. exkl. obligatorische Vollkasko-Motorfahrzeugversicherung. AMAG Basic PLUS beinhaltet die Dienstleistungen Service, bestimmte Flüssigkeiten, Verschleiss und 3 Monate Garantieverlängerung geschenkt. 1.74% AMAG Advanced PLUS für alle Occasion Elektrofahrzeugmodelle der VW-Konzernmarken. Gültig bei Abschluss eines AMAG Advanced PLUS bis 30.09.2024 oder bis auf Widerruf auf sofort verfügbare Elektrofahrzeuge (Occasionen >1000km). Rechnungsbeispiel mit Kaufpreis: CHF 45’000.–. Effektiver Jahreszins: 2.01%, Laufzeit: 48 Monate (10‘000 km Jahr), Sonderzahlung 20%: CHF 9’000.–, Leasingrate: CHF 488.- Mt. exkl. obligatorische Vollkasko-Motorfahrzeugversicherung. AMAG Advanced PLUS beinhaltet die Dienstleistungen Service, bestimmte Flüssigkeiten, Reifenkontingent gemäss Laufzeit, Laufleistung sowie Räder- oder Reifenwechsel und 6 Monate Garantieverlängerung geschenkt. Vertragsabschlüsse #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Garantieverlängerung geschenkt. Vertragsabschlüsse über Occasionsfahrzeuge bis 30.06.2024 oder bis auf Widerruf. Das Fahrzeug darf nach Ablauf des Leasingvertrages nicht älter als 8 Jahre alt sein (Datum erste Inverkehrsetzung ist massgebend.) Der Kilometerstand darf nach Ablauf des Leasingvertrages nicht mehr als 180 000 km aufweisen. Finanzierung über AMAG Leasing AG. Nur bei teilnehmenden AMAG Retail Betrieben. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Änderungen vorbehalten. Solange Vorrat #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Leasing ab CHF 249: Berechnungsbeispiel Leasing: Barkaufpreis: CHF 35’999.–. Effektiver Jahreszins: 4.07 %, Laufzeit: 48 Monate (10’000 km Jahr), Sonderzahlung CHF 7’112.–, Leasingrate Fahrzeug: CHF 248.51 Mt. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Finanzierung über die AMAG Leasing AG. Gültig nur für Lagerfahrzeuge. Aktion gültig bis 31.08.2024. Bereits bestehende Leasinganträge können nicht rückwirkend angepasst werden. Das Leasing ist nicht kumulierbar mit Flottenkonditionen. Nur bei teilnehmenden AMAG Betrieben und nur solange Vorrat. Änderungen Hilfe & Kontakt Kontakt Online-Termin FAQ Online-Autokauf Firmenkunden Newsletter Notfall Auto finden & Service Auto finden Service Garage suchen Leasing Auto Abo Europcar Carsharing Parking Unternehmen Über uns AMAG Group Nachhaltigkeit Jobs & Karriere Presse Unsere Marken AMAG App Get connected with AMAG © 2024 AMAG Automobil und Motoren AG Datenschutzerklärung Rechtliche Hinweise Rechtliche Hinweise Online-Chat Cookie-Richtlinie Impressum AGB Jobs #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Der Schutz Ihrer Privatsphäre ist uns wichtig. Wir nutzen Cookies, um Ihr Erlebnis auf unserer Webseite zu optimieren und unsere Kommunikation mit Ihnen zu verbessern. Die Arten von Cookies, die wir einsetzen, werden unter «Cookie-Einstellungen» beschrieben. Wir berücksichtigen hierbei Ihre Präferenzen und verarbeiten Daten für Marketing, Analytics und Personalisierung nur, wenn Sie uns Ihre Einwilligung geben. Weitere Informationen zum Datenschutz finden Sie hier. Cookie-Einstellungen Alle ablehnen Alle erlauben #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: SCHNELL UND ONLINE Wir kaufen Ihr Auto AMAG GROUP Mobilität, Nachhaltigkeit & Zukunft NR. 1 IN DER SCHWEIZ Mit 85 Standorten Auto finden Service Garage suchen Jobs Meine Garage DE Exklusiv bei Online-Leasing Entdecken Sie exklusive Online Leasing-Deals Jetzt online Leasing abschliessen Marke - - - AUDI CUPRA SEAT Å koda VW VW Nutzfahrzeuge - - - Alfa Romeo Bentley BMW Chevrolet Citroën Dacia Fiat Ford Honda Hyundai Jaguar Jeep Kia Land Rover Maserati Mazda Mercedes-Benz Micro MINI Mitsubishi Nissan Opel Peugeot Porsche Renault Smart Subaru Suzuki Toyota Volvo - - - Andere Modell SUCHE SPEICHERN Fahrzeugdaten 1 Ausstattung 0 PROMOTIONEN Exklusiv bei Online-Leasing Spezial Elektro Leasing Online-Deals Leasing ab CHF 249 NEUHEITEN Bald verfügbar INVERKEHRSETZUNG Jahr Alle Ab 2024 Ab 2023 Ab 2022 Ab 2021 Ab 2020 Ab 2019 Ab 2018 Ab 2017 Ab 2016 Ab 2015 Ab 2014 Ab 2013 Ab 2012 Ab 2011 Ab 2010 Ab 2009 Ab 2008 Ab 2007 Ab 2006 Ab 2005 PREIS (CHF) Kauf Leasing #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Kauf Leasing KAUFPREIS von Alle 3’000 4’000 5’000 7’500 10’000 12’500 15’000 17’500 20’000 22’500 25’000 30’000 35’000 40’000 45’000 50’000 60’000 70’000 80’000 90’000 100’000 125’000 150’000 175’000 200’000 bis Alle 3’000 4’000 5’000 7’500 10’000 12’500 15’000 17’500 20’000 22’500 25’000 30’000 35’000 40’000 45’000 50’000 60’000 70’000 80’000 90’000 100’000 125’000 150’000 175’000 200’000 STANDORT Alle KRAFTSTOFFART Benzin Diesel Hybrid Elektro Gas H2 ANTRIEB Front Heck Allrad GETRIEBE Automatik Schaltung FAHRZEUGART #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: GETRIEBE Automatik Schaltung FAHRZEUGART Neu-/Lagerfahrzeuge Occasionen Vorführwagen Elektrofahrzeuge Abo KILOMETERSTAND von Alle 1’000 5’000 10’000 20’000 30’000 40’000 50’000 60’000 70’000 80’000 90’000 100’000 110’000 120’000 130’000 140’000 150’000 bis Alle 1’000 5’000 10’000 20’000 30’000 40’000 50’000 60’000 70’000 80’000 90’000 100’000 110’000 120’000 130’000 140’000 150’000 LEISTUNG (PS) von Alle 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 bis Alle 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 KAROSSERIEVARIANTE Alle Limousine Kombi Cabriolet Coupé Van/Kleinbus SUV / Geländewagen Pickup Nutzfahrzeuge / Camper ANZAHL SITZE von Alle 1 2 3 4 5 6 7 8 bis Alle 2 3 4 5 6 7 8 9 #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: ANZAHL TÜREN von Alle 2 3 4 5 bis Alle 2 3 4 5 FARBE ( AUSSEN ) Alle anthrazit beige blau bordeaux braun gelb gold grau grün mehrfarbig orange pink rot schwarz silber türkis violett weiss FARBE ( INNEN ) Alle anthrazit beige blau braun bronze gelb gold grau grün mehrfarbig orange rot schwarz silber violett weiss REFERENZ-NUMMER ALLE FILTER (1) ZURÜCKSETZEN EXKLUSIV BEI ONLINE-LEASING Entdecken Sie exklusive Online Leasing-Deals Jetzt abschliessen 101 Fahrzeuge verfügbar 161 Exklusiv bei Online-Leasing: Profitieren Sie bei sämtlichen Occasionsfahrzeugen, die auf auto.amag.ch als Online Deal gekennzeichnet sind beim Abschluss eines Leasingvertrages über auto.amag.ch bis 30.09.2024 oder bis auf Widerruf von einem 3.99% Leasing. Berechnungsbeispiel mit Fahrzeugpreis CHF 44’310. Effektiver Jahreszins 4,06%, Laufzeit: 48 Mt. (15’000 km Jahr), Sonderzahlung: CHF 0.-, Leasingrate: CHF 612.– Mt., inkl. MwSt., exkl. obligatorischer Vollkaskoversicherung. Aktion nur gültig so lange Vorrat. Änderungen vorbehalten. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Finanzierung über AMAG Leasing AG. Jetzt online Leasing abschliessen Aktuell sind 101 Fahrzeuge für Sie verfügbar. #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Ihre Suchergebnisse ALLE FILTER ZURÜCKSETZEN Sortieren Nach Name Preis aufsteigend Preis absteigend Nach Kilometer Jahrgang neuste Jahrgang älteste in Aufbereitung EXKLUSIV BEI ONLINE-LEASING #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: VW Arteon Shooting Brake R-Line CHF 44’450.- Leasing ab CHF 403.- /Monat 31’200 km 05/2023 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW Passat Variant Elegance CHF 33’950.- Leasing ab CHF 304.- /Monat 41’500 km 12/2022 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING SEAT IBIZA FR CHF 23’700.- Leasing ab CHF 219.- /Monat 20’600 km 05/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING AUDI Q3 40 TFSI advanced CHF 30’900.- Leasing ab CHF 369.- /Monat 47’800 km 05/2019 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VWNF California 6.1 Ocean Liberty CHF 68’900.- Leasing ab CHF 651.- /Monat 15’000 km 01/2022 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING VWNF California 6.1 Beach Liberty CHF 65’900.- Leasing ab CHF 512.- /Monat 18’200 km 04/2023 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING Å koda SUPERB Sportline "Light" CHF 34’500.- Leasing ab CHF 306.- /Monat 55’000 km 06/2022 Diesel Automatik Abo EXKLUSIV BEI ONLINE-LEASING Å koda KAROQ ''Smile'' (netto) CHF 20’100.- #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: CHF 20’100.- Leasing ab CHF 224.- /Monat 88’660 km 04/2019 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING Å koda Kamiq Ambition CHF 27’430.- Leasing ab CHF 257.- /Monat 33’000 km 06/2023 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING AUDI RS 6 Avant CHF 94’900.- Leasing ab CHF 959.- /Monat 73’058 km 09/2020 Benzin MHEV Automatik EXKLUSIV BEI ONLINE-LEASING Å koda Octavia Style CHF 34’900.- Leasing ab CHF 292.- /Monat 9’000 km 09/2023 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW T-Roc Advance CHF 22’900.- Leasing ab CHF 294.- /Monat 43’846 km 08/2018 Benzin Schaltung EXKLUSIV BEI ONLINE-LEASING VW T-Cross Life CHF 21’900.- Leasing ab CHF 230.- /Monat 71’200 km 10/2020 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW Polo Style CHF 24’990.- Leasing ab CHF 255.- /Monat 21’200 km 07/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING AUDI TT Roadster CHF 26’770.- Jetzt Offerte einholen 82’900 km 08/2015 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Automatik EXKLUSIV BEI ONLINE-LEASING VW Tiguan Highline CHF 27’970.- Leasing ab CHF 308.- /Monat 68’115 km 09/2018 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING VW Tiguan Starter CHF 22’490.- Leasing ab CHF 214.- /Monat 48’500 km 12/2020 Benzin Schaltung Abo EXKLUSIV BEI ONLINE-LEASING VW Tiguan Elegance CHF 41’950.- Leasing ab CHF 344.- /Monat 24’500 km 07/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING Å koda Scala Ambition CHF 24’950.- Leasing ab CHF 226.- /Monat 24’900 km 03/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING VW Polo Life CHF 22’900.- Leasing ab CHF 218.- /Monat 16’600 km 07/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING Å koda Karoq SportLine CHF 41’900.- Leasing ab CHF 389.- /Monat 22’990 km 04/2023 Benzin Automatik Abo EXKLUSIV BEI ONLINE-LEASING VWNF California 6.1 Ocean Liberty CHF 71’450.- Leasing ab CHF 552.- /Monat 11’900 km 06/2023 Diesel Automatik EXKLUSIV BEI ONLINE-LEASING AUDI Q2 40 TFSI sport #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: AUDI Q2 40 TFSI sport CHF 33’400.- Leasing ab CHF 382.- /Monat 52’300 km 08/2020 Benzin Automatik EXKLUSIV BEI ONLINE-LEASING AUDI Q5 55 TFSI e sport CHF 38’900.- Leasing ab CHF 450.- /Monat 69’600 km 09/2019 Hybrid Automatik Abo 24 Fahrzeuge pro Seite 48 Fahrzeuge pro Seite 72 Fahrzeuge pro Seite 96 Fahrzeuge pro Seite «12345» Exklusiv bei Online-Leasing: Profitieren Sie bei sämtlichen Occasionsfahrzeugen, die auf auto.amag.ch als Online Deal gekennzeichnet sind beim Abschluss eines Leasingvertrages über auto.amag.ch bis 30.09.2024 oder bis auf Widerruf von einem 3.99% Leasing. Berechnungsbeispiel mit Fahrzeugpreis CHF 44’310. Effektiver Jahreszins 4,06%, Laufzeit: 48 Mt. (15’000 km Jahr), Sonderzahlung: CHF 0.-, Leasingrate: CHF 612.– Mt., inkl. MwSt., exkl. obligatorischer Vollkaskoversicherung. Aktion nur gültig so lange Vorrat. Änderungen vorbehalten. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Finanzierung über AMAG Leasing AG. #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Spezial Elektro Leasing: 2.99% AMAG Basic PLUS für alle Occasion Elektrofahrzeugmodelle der VW-Konzernmarken. Gültig bei Abschluss eines AMAG Basic PLUS bis 30.09.2024 oder bis auf Widerruf auf sofort verfügbare Elektrofahrzeuge (Occasionen >1000km). Rechnungsbeispiel mit Kaufpreis: CHF 59’710.–. Effektiver Jahreszins: 3.03%, Laufzeit: 48 Monate (15‘000 km Jahr), Sonderzahlung 0%: CHF 0.–, Leasingrate: CHF 758.44.- Mt. exkl. obligatorische Vollkasko-Motorfahrzeugversicherung. AMAG Basic PLUS beinhaltet die Dienstleistungen Service, bestimmte Flüssigkeiten, Verschleiss und 3 Monate Garantieverlängerung geschenkt. 1.74% AMAG Advanced PLUS für alle Occasion Elektrofahrzeugmodelle der VW-Konzernmarken. Gültig bei Abschluss eines AMAG Advanced PLUS bis 30.09.2024 oder bis auf Widerruf auf sofort verfügbare Elektrofahrzeuge (Occasionen >1000km). Rechnungsbeispiel mit Kaufpreis: CHF 45’000.–. Effektiver Jahreszins: 2.01%, Laufzeit: 48 Monate (10‘000 km Jahr), Sonderzahlung 20%: CHF 9’000.–, Leasingrate: CHF 488.- Mt. exkl. obligatorische Vollkasko-Motorfahrzeugversicherung. AMAG Advanced PLUS beinhaltet die Dienstleistungen Service, bestimmte Flüssigkeiten, Reifenkontingent gemäss Laufzeit, Laufleistung sowie Räder- oder Reifenwechsel und 6 Monate Garantieverlängerung geschenkt. Vertragsabschlüsse #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Garantieverlängerung geschenkt. Vertragsabschlüsse über Occasionsfahrzeuge bis 30.06.2024 oder bis auf Widerruf. Das Fahrzeug darf nach Ablauf des Leasingvertrages nicht älter als 8 Jahre alt sein (Datum erste Inverkehrsetzung ist massgebend.) Der Kilometerstand darf nach Ablauf des Leasingvertrages nicht mehr als 180 000 km aufweisen. Finanzierung über AMAG Leasing AG. Nur bei teilnehmenden AMAG Retail Betrieben. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Änderungen vorbehalten. Solange Vorrat #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Leasing ab CHF 249: Berechnungsbeispiel Leasing: Barkaufpreis: CHF 35’999.–. Effektiver Jahreszins: 4.07 %, Laufzeit: 48 Monate (10’000 km Jahr), Sonderzahlung CHF 7’112.–, Leasingrate Fahrzeug: CHF 248.51 Mt. Die Kreditvergabe ist verboten, falls sie zur Überschuldung des Konsumenten führt. Finanzierung über die AMAG Leasing AG. Gültig nur für Lagerfahrzeuge. Aktion gültig bis 31.08.2024. Bereits bestehende Leasinganträge können nicht rückwirkend angepasst werden. Das Leasing ist nicht kumulierbar mit Flottenkonditionen. Nur bei teilnehmenden AMAG Betrieben und nur solange Vorrat. Änderungen Hilfe & Kontakt Kontakt Online-Termin FAQ Online-Autokauf Firmenkunden Newsletter Notfall Auto finden & Service Auto finden Service Garage suchen Leasing Auto Abo Europcar Carsharing Parking Unternehmen Über uns AMAG Group Nachhaltigkeit Jobs & Karriere Presse Unsere Marken AMAG App Get connected with AMAG © 2024 AMAG Automobil und Motoren AG Datenschutzerklärung Rechtliche Hinweise Rechtliche Hinweise Online-Chat Cookie-Richtlinie Impressum AGB Jobs #################### File: amag-ch-de-promotions-2024-online-deals-html-28919.txt Page: 1 Context: Der Schutz Ihrer Privatsphäre ist uns wichtig. Wir nutzen Cookies, um Ihr Erlebnis auf unserer Webseite zu optimieren und unsere Kommunikation mit Ihnen zu verbessern. Die Arten von Cookies, die wir einsetzen, werden unter «Cookie-Einstellungen» beschrieben. Wir berücksichtigen hierbei Ihre Präferenzen und verarbeiten Daten für Marketing, Analytics und Personalisierung nur, wenn Sie uns Ihre Einwilligung geben. Weitere Informationen zum Datenschutz finden Sie hier. Cookie-Einstellungen Alle ablehnen Alle erlauben #################### File: LeitfadenCO2.pdf Page: 1 Context: # CO₂-Leitfaden ## Wird der Leitfaden zum Energieverbrauch und zu den CO₂-Emissionen **Online abrufbar unter:** [https://www.dat.de/co2/](https://www.dat.de/co2/) Aus Gründen der leichteren Recherche und um Papier zu sparen, wird dieser Leitfaden nur noch online zur Verfügung gestellt und regelmäßig aktualisiert. --- © Deutsche Automobil Treuhand GmbH | Hellmuth-Hirth-Straße 1 | 73760 Ostfildern Image Analysis: ### Comprehensive Analysis of the Visual Content #### 1. Localization and Attribution - **Image 1**: The image occupies the entire visual content provided. #### 2. Object Detection and Classification - **Image 1**: - **Objects Detected**: - Text blocks - A logo featuring the text "DAT" and an icon of a car and a document. - **Classified Categories**: - Informational text - Corporate logo - **Key Features**: - The text is predominantly in German, organized in a structured format. - The logo is registered clearly in the upper right-hand corner with distinct yellow and blue colors. #### 3. Scene and Activity Analysis - **Image 1**: - **Scene Description**: - The image appears to be a digital flyer or advertisement. - It is highly focused on providing information regarding CO2 emissions guidelines. - **Activities**: - The main activity involves reading and possibly following the provided online link. #### 4. Text Analysis - **Image 1**: - **Detected Text**: ``` Automobiles Wissen beginnt mit uns. AUS DEM CO²-LEITFADEN WIRD DER LEITFADEN ZUM ENERGIEVERBRAUCH UND ZU DEN CO²-EMISSIONEN ONLINE ABRUFBAR UNTER: https://www.dat.de/co2/ Aus Gründen der leichteren Recherche und um Papier zu sparen, wird dieser Leitfaden nur noch online zur Verfügung gestellt und regelmäßig aktualisiert. © Deutsche Automobil Treuhand GmbH | Helmut-Hirth-Straße 1 | 73760 Ostfildern ``` - **Content Significance**: - The text describes a transition from a printed guideline on CO2 emissions to an online version. - It highlights the benefits of this transition for easier research and environmental friendliness. - A clear call to action is provided with a URL to access the guidelines online. #### 8. Color Analysis - **Image 1**: - **Dominant Colors**: - Blue: Used prominently in headings and the logo, conveying trust and professionalism. - Yellow: Accents the logo in the upper right, suggesting attention to detail. - White and Grey: Provide a neutral background that makes the text readable and highlights the main informational content. - **Impact on Perception**: - The blue text stands out against the white background, capturing attention and signifying importance. - Yellow elements draw attention towards the logo, enhancing brand recognition. #### 9. Perspective and Composition - **Image 1**: - **Perspective**: - The image uses a straightforward front-facing perspective which is typical for informational material. - **Composition**: - The elements are centered and well-aligned, providing a balanced visual presentation. - Text blocks are organized hierarchically, leading the eye from important heading information to detailed explanations. #### 10. Contextual Significance - **Image 1**: - **Overall Document Context**: - As an informational flyer or digital advertisement, this image serves to notify and direct readers to a specific online resource on CO2 emissions. - **Contribution to Message**: - The image communicates effectively about the shift to an online guide, emphasizing accessibility and environmental considerations. ### Summary The visual content is a well-designed informational advertisement for the Deutsche Automobil Treuhand GmbH, focusing on a transition to an online CO2 emissions guide. The use of clear and well-organized text, along with highlighted colors, effectively draws attention to the key message and call to action. #################### File: LeitfadenCO2.pdf Page: 1 Context: # Aus dem CO₂-Leitfaden ## Wird der Leitfaden zum Energieverbrauch und zu den CO₂-Emissionen **Online abrufbar unter:** [https://www.dat.de/co2/](https://www.dat.de/co2/) Aus Gründen der leichteren Recherche und um Papier zu sparen, wird dieser Leitfaden nur noch online zur Verfügung gestellt und regelmäßig aktualisiert. © Deutsche Automobil Treuhand GmbH | Hellmut-Hirth-Straße 1 | 73760 Ostfildern Image Analysis: ### Image Analysis #### Localization and Attribution: - **Image Number**: Image 1 - **Location on Page**: Center of a single-page document. #### Object Detection and Classification: - **Objects Identified**: This image primarily consists of text and logos. The key detected elements are: - Text blocks. - Logos (top right: yellow background, black icon of a car and another symbol). #### Text Analysis: - **Extracted Text**: ``` Automobiles Wissen beginnt mit uns. AUS DEM CO2-LEITFADEN WIRD DER LEITFADEN ZUM ENERGIEVERBRAUCH UND ZU DEN CO2-EMISSIONEN ONLINE ABRUFBAR UNTER: https://www.dat.de/co2/ Aus Gründen der leichteren Recherche und um Papier zu sparen, wird dieser Leitfaden nur noch online zur Verfügung gestellt und regelmäßig aktualisiert. © Deutsche Automobil Treuhand GmbH | Helmut-Hirth-Straße 1 | 73760 Ostfildern ``` - **Text Significance**: - The text indicates that a guideline on CO2 emissions is available online. - The guideline has been renamed from "CO2-Leitfaden" to a more comprehensive guide on energy consumption and CO2 emissions. - The intent is to provide the guide online only, for reasons of easier research and paper-saving. - The website link provided (https://www.dat.de/co2/) redirects users to where they can access the digital version of the guide. #### Color Analysis: - **Dominant Colors**: - **Blue**: For text headers and the background of the top left corner. - **White**: As the primary background color. - **Yellow**: Used in the bottom left corner and part of the logo. - **Gray**: Used for auxiliary text and background pattern. - **Impact on Perception**: - The color scheme provides a professional and clean appearance, which is suitable for an informational document. - The use of blue conveys trust and reliability, while yellow adds a touch of energy and emphasis. #### Perspective and Composition: - **Perspective Description**: The image is taken from a straight-on perspective with a flat background. - **Composition Analysis**: - The main text is centrally aligned. - Logos are strategically placed to ensure branding visibility. - The layout is hierarchical, with the most important information (title and online link) displayed prominently in larger fonts. #### Contextual Significance: - **Overall Contribution**: - This image serves as a promotional and informational piece, likely from a digital or printed document by Deutsche Automobil Treuhand GmbH. - It emphasizes the shift towards online resources and the importance of keeping such guidelines updated continuously. - The image reinforces the commitment to providing accessible information on CO2 emissions and energy consumption. ### Summary: The image is a centralized informational graphic that highlights the update and availability of a guide on CO2 emissions and energy consumption. It underscores the importance of transitioning to online resources for easier accessibility and environmental considerations, featuring a clean, professional design consistent with the document’s purpose. ########## """QUERY: Schreib mir eine zusammenfassung von Öle und Lacke""" Consider the chat history for relevant information. Use all information included. Use as much tokens as needed. Important: If you find information separated by a | in the context, it is a table formatted in Markdown.Important: Take a look at the QUERY and only the QUERY. If this is vague or unclear, please ignore everything and ask a follow-up question instead! Final Files Sources: 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 2, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 3, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 4, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 5, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 6, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 7, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 8, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 9, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 10, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 11, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 12, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 13, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 14, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 15, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 16, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 17, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 18, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 19, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 20, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 21, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 22, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 23, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 24, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 25, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 26, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 27, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 28, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 29, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 30, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 31, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 32, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 33, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 34, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 35, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 36, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 37, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 38, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 39, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 40, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 41, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 42, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 43, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 44, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 45, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 46, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 47, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 48, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 49, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 50, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 51, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 52, 15%20MB%20Computer%20Networking%20Principles%2C%20Protocols%20and%20Practice%20%28HTML%2C%20ePub%2C%20PDF%2C%20Kindle%29%281%29.pdf - Page 53, amag-ch-28917.txt - Page 1, amag-ch-de-28918.txt - Page 1, amag-ch-de-promotions-2024-online-deals-html-28919.txt - Page 1, LeitfadenCO2.pdf - Page 1 ================================================== **Elapsed Time: 7.08 seconds** ================================================== FINAL ANSWER Answer: Es scheint, dass die bereitgestellten Dokumente und der Kontext keine spezifischen Informationen zu "Öle und Lacke" enthalten. Die Dokumente behandeln hauptsächlich Themen wie Computer Networking, Automobilangebote und -dienstleistungen sowie CO₂-Leitfäden. Um eine präzise und relevante Zusammenfassung zu "Öle und Lacke" zu erstellen, benötige ich spezifische Informationen oder Abschnitte, die sich mit diesem Thema befassen. Könnten Sie bitte genauere Informationen oder den spezifischen Kontext zu "Öle und Lacke" bereitstellen? Alternativ können Sie mir auch sagen, in welchem Dokument oder Abschnitt ich nach diesen Informationen suchen soll. ================================================== **Elapsed Time: 0.00 seconds** ==================================================