It has been nearly ten years since the 5th Edition of Computer Networks: A Systems Approach was published. Much has changed in that time, most notably, the explosion of the cloud and smartphone apps onto the scene. In many ways, this is reminiscent of the dramatic affect the Web was having on the Internet when we published the 1st Edition of the book in 1996.
The 6th Edition adapts to the times, but keeps the Systems Approach as its north star. In broad strokes, we update and improve this new edition in four main ways:
- We refresh the examples to reflect the current state of the world. This includes deleting anachronisms (e.g., dial-up modem), using popular applications (e.g., Netflix, Spotify) to motivate the problems being addressed, and updating the numbers to represent the state-of-the-art technology (e.g., 10-Gbps Ethernet).
- We connect the dots between the original research that led to the development of technologies like multicast, real-time video streaming, and quality-of-service, and the now-familar cloud applications like GoToMeeting, Netflix, and Spotify. This is in keeping with our emphasis on the design process and not just the end result, which is especially important today since so much the Internet is primarily available in proprietary commercial services.
- We place the Internet in the broader context of the Cloud, and just as importantly, in the context of the commerial forces that are shaping the Cloud. This has minimal impact on the technical details presented throughout the book, but it is discussed in a new Perspective section at the end of each chapter. We hope one side-effect of this discussion is to foster an appreciation for the Internet’s continuous evolution, and the opportunity for innovation this represents.
- We distill the important principles of network design in a series of Key Takeaways throughout the book. Each takeaway is a concise statement of either a general system design rule or a fundamental networking concept, drawing on the examples presented in the surrounding text. Pedagogically, these takeaways correspond to the high-level learning objectives for the book.
More specifically, the 6th Edition includes the following major changes:
- New Perspective Section in Chapter 1 introduces the recurring Cloudification theme.
- New Section 2.8 describes the Access Network, including Passive Optical Networks (PON) and 5G’s Radio Access Networks (RAN).
- Refactored topics across Sections 3.1 (Switching Basics) and 3.2 (Switched Ethernet), including expanded coverage of VLANs.
- Section 3.5 updated to include descriptions of White-Box Switches and Software-Defined Networks (SDN).
- New Perspective Section in Chapter 3 describes VXLANs and the role of overlays in the Cloud.
- Refactored topics across Sections 4.1 (Global Internet) and 4.2 (IP Version 6).
- New Perspective Section in Chapter 4 describes how the Cloud impacts the Internet’s structure.
- Section 5.2 expanded to include a discussion of QUIC.
- Section 5.3 expanded to include a description of gRPC.
- Sections 6.3 and 6.4 updated to include descriptions of TCP CUBIC, DCTCP, and BBR.
- Section 6.4 expanded to include a description of Active Queue Management (AQM).
- Section 7.1 expanded to include a desciption of Protocol Buffers.
- Section 7.2 expanded to include a desciption of HTTP Adaptive Streaming.
- New Section 8.1 introduces the duality of Threats and Trust.
- Refactored topics across Sections 8.3 (Key Predistribution) and 8.4 (Authentication Protocols).
- New Perspective Section in Chapter 8 describes Decentralized Identity Management and the role of Blockchains.
- Section 9.1 updated to include a description of HTTP/2, along with a discussion of REST, gRPC, and Cloud Services.
- Section 9.3 expaned to include a description of modern Network Management Systems including the use of OpenConfig and gNMI.
To construct a networking course around the material in this book, it can be helpful to understand the overall organization, which can be characterized as having three major parts:
- Conceptual and foundational material, that is, the big ideas at the heart of networking.
- Core protocols and algorithms that illustrate how the foundational ideas are put to practice.
- Advanced material that might or might not fit in any single semester course.
This characterization can be applied at the Chapter level: Chapter 1 is foundational, Chapters 2, 3, 5, and 9 are core, and Chapters 4, 6, 7, and 8 cover more advanced topics.
This characterization can also be applied at the Section level, where roughly speaking, each Chapter advances from basic concepts to specific technology to advanced techniques. For example, Chapter 3 starts by introducing the basics of switched networks (3.1), then covers the specifics of Switched Ethernet and the IP Internet (3.2-3.4), and concludes with an optional discusion of SDN (3.5). Similarly, Chapter 6 starts with foundational ideas (6.1-6.2), then explores TCP congestion control (6.3), and concludes with optional advanced material (6.4-6.5).
We would like to acknowledge the following people for their help with new content:
- Larry Brakmo: TCP Congestion Control
- Carmelo Cascone: White-Box Switches
- Charles Chan: White-Box Switches
- Jude Nelson: Decentralized Identity
- Oguz Sunay: Cellular Networks
- Thomas Vachuska: Network Management
Along with the following individuals (github users) for their various contributions and bug fixes:
.. hlist:: :columns: 3 - Mohammed Al-Ameen - Andy Bavier - Manuel Berfelde - Chris Goldsworthy - John Hartman - Diego López León - Matteo Scandolo - Mike Wawrzoniak - 罗泽轩 (spacewander) - Arnaud (arvdrpoo) - Desmond (kingdido999) - Guo (ZJUGuoShuai) - Hellman (eshellman) - Xtao (vertextao) - Mike Appelman - Seth (springbov)
Finally, we would like to thank the following reviewers for their many helpful comments and suggestions. Their impact was significant.
- Mark J. Indelicato, Rochester Institute of Technology
- Michael Yonshik Choi, Illinois Institute of Technology
- Sarvesh Kulkarni, Villanova University
- Alexander L. Wijesinha, Towson University