Preface

This book is about the next generation Internet protocol. We have become familiar with the strengths and weaknesses of IPv4; we know how to design and configure it, and we have learned how to troubleshoot it. And now we have to learn a new protocol? Start from scratch? Not really. The designers of IPv6 have learned a lot from over 15 years of experience with IPv4, and they have been working on the new protocol since the early 1990s. They retained the strengths of IPv4, extended the address space from 32 bits to 128 bits, and added functionality that is missing in IPv4. They developed transition mechanisms that make IPv4 and IPv6 coexist peacefully and that guarantee a smooth transition between the protocols. In fact, this was one of the major requirements for the development of the new protocol version.

So you do not need to forget what you know about IPv4; many things will feel familiar with IPv6. When you get started, you will discover new features and functionalities that will make your life a lot easier. IPv6 has features that you will need in tomorrow's networksfeatures that IPv4 does not provide. The day will come when our Personal Digital Assistants (PDAs) and mobile phones have IP addresses. Aside from the fact that the IPv4 address space could never cover the demand for that number of IP addresses, imagine configuring those devices with the means we have today!

One of the coolest features built into IPv6 is the autoconfiguration capability. Haven't we always struggled with IP address assignment? The advent of DHCP made our lives a little easier, but now we need to maintain and troubleshoot the DHCP servers. And when our refrigerator, our PDA, and our TV each have an IP address, will we need a DHCP server at home? Not with autoconfiguration. If you have an IPv6-enabled host, you can plug it into your network, and it will configure automatically for a valid IPv6 address. Internet Control Message Protocol (ICMP), which is a networker's best friend, has become much more powerful with IPv6. Many of the new features of IPv6, such as autoconfiguration, optimized multicast routing and multicast group management, Neighbor Discovery, path MTU discovery, and Mobile IPv6 are based on ICMPv6.

I hope that this book will help you to become familiar with the protocol and provide an easy-to-understand entry point and guide to exploring this new area.

Audience

This book covers a broad range of information about IPv6 and is an excellent resource for anybody who wants to understand or implement the protocol. Whether you are the owner or manager of a company or an IT department; whether you are a system or network administrator, an engineer, or a network designer; or whether you are just generally interested in learning about the important changes with IPv6, this book discusses economic and strategic aspects as well as technical details. I describe interoperability mechanisms and scenarios that ensure a smooth introduction of IPv6. Quick start guides for different operating systems help with the first hands-on steps. If you are a company owner or manager, you will be most interested in Chapters 1 and 10. If you need to plan your corporate network strategy, you will be most interested in Chapters 1, 4, 8, 9, and 10. If you manage the infrastructure in your company, you will especially be interested in Chapters 4, 7, and 8, which cover ICMPv6, Layer 2 issues and routing, and in Chapter 10, which addresses interoperability. If you are a system or network administrator, all chapters are relevant: this book provides a foundation for IPv6 implementation and integration with IPv4.

About This Book

This book covers IPv6 in detail and explains all the new features and functions. It will show you how to plan for, design, and integrate IPv6 in your current IPv4 infrastructure. It also teaches you what you need to know to get started, to configure IPv6 on your hosts and routers, and to find the right applications that support IPv6.

Now that you know what this book is about, I should explain this this book is not written for developers. This doesn't mean you should not be reading it if you are a developer. If you do read it, you will understand the implications of introducing IPv6 in your network and how important it is to develop cool applications for IPv6. If you need a specific guide to developing for IPv6, look for developer resources.

This book assumes that you have a good understanding of network issues in general and a familiarity with IPv4. It is beyond the scope of this book to discuss IPv4 concepts in detail. I refer to them when necessary, but if you want to learn more about IPv4, there are a lot of good resources on the market. You can find a list of books in Appendix C.

Organization

This book is organized so that a reader familiar with IPv4 can easily learn about the new features in IPv6 by reading Chapters 2 through 6. These chapters cover what you need to know about addressing, the new IPv6 header, ICMPv6, security, and Quality of Service (QoS). Chapters 7 through 11 cover topics such as networking aspects, support of different link-layer services, routing, upper layer protocol support, the transition mechanisms that make IPv6 interoperable with IPv4, and Mobile IPv6. Chapter 12 is a quick-start guide and includes a short description of how different operating systems are configured for IPv6. Here is a chapter-by-chapter breakdown of the book:

• Chapter 1, Why IPv6?, briefly explains the history of IPv6 and gives an overview of the new functionality. It draws a bigger picture of Internet and service evolution, showing that the large address space and the advanced functionality of IPv6 are much needed for different reasons. It then discusses the most common misconceptions that prevent people from exploring and integrating the protocol, and provides a summary of the most important steps to undertake today, along with a picture of what is happening around the world.

• Chapter 2, The Structure of the IPv6 Protocol, describes the new IPv6 header format with a discussion of each field and trace file examples. It also describes what Extension headers are, what types of Extension headers have been defined, and how they are used.

• Chapter 3, IPv6 Addressing, explains everything you need to know about the new address format, address notation, address types, international registry services, and prefix allocation.

• Chapter 4, ICMPv6, describes the new ICMPv6 message format, the ICMPv6 Error messages and Informational messages, and the ICMPv6 header in the trace file. This chapter also discusses the extended functionality based on ICMPv6, such as Neighbor Discovery, Autoconfiguration, Path MTU Discovery, and Multicast Listener Discovery (MLD). You will learn how ICMPv6 makes an administrator's life easier.

• Chapter 5, Security with IPv6, begins with a short discussion of basic security concepts and requirements. It then covers the IPsec framework, security elements available in IPv6 for authentication and encryption, and how they are used. Our future networks will require new security architectures. This chapter includes a description of a new model.

• Chapter 6, Quality of Service, discusses basic requirements and types of QoS. I explain the QoS elements available in IPv6 and how they can be implemented. I also describe different QoS architectures and introduce further work in this area.

• Chapter 7, Networking Aspects, discusses Layer 2 support for IPv6 (Ethernet, Token Ring, ATM, frame relay, etc.), the mapping of multicast addresses to Layer 2 addresses, and the Detecting Network Attachment (DNA) working group.

• Chapter 8, Routing Protocols, discusses the advanced routing features of IPv6 and covers the available routing protocols such as RIPng, OSPFv3 for IPv6, and BGP extensions for IPv6, IS-IS, and EIGRPv6. (This chapter was written by Stefan Marzohl.)

• Chapter 9, Upper-Layer Protocols, discusses what is going on above the IP layer, starting with changes for TCP and UDP, continuing with a detailed discussion of the DHCPv6 specification, DNS extensions for IPv6, SLPv2 in IPv6 networks, FTP, Telnet, and web servers.

• Chapter 10, Interoperability, discusses the different transition mechanisms that have been defined, such as dual-stack operation, tunneling, and translation techniques. It also shows how they can be used and combined to ensure peaceful coexistence and smooth transition. A broad variety of case studies show that IPv6 is mature enough to be introduced and that there are many ways to do this. It also provides an overview of what is still missing, security and application aspects, vendor status, and the cost of introduction.

• Chapter 11, Mobile IPv6, covers Mobile IPv6. This chapter explains why this technology will become the foundation for a new generation of mobile services.

• Chapter 12, Get Your Hands Dirty, explains how to get started with IPv6 on different operating systems, such as Sun Solaris, Linux, BSD, Windows 2003, Windows XP, Mac OS, and a Cisco router. It introduces the most common IPv6 tools available for each operating system. This chapter also explains what I did in my lab and provides examples of trace files.

• Appendix A, RFCs, includes a short introduction to the RFC process and authorities, and provides a list of relevant RFCs for IPv6.

• Appendix B, IPv6 Resources, reflects the chapter organization of the book and provides summaries of all indexes, protocol numbers, message types, and address allocations.

• Appendix C, Recommended Reading, provides a list of books that I recommend.

Some important topics and information appear in multiple places in the book. This is not because I want to bore you, but because I assume that most readers will not read the book from the first page to the last page, but rather will pick and choose chapters and sections depending on interest. So if the information is important with regard to different sections and contexts, I may mention it again.

Conventions Used in This Book

I use the following font conventions in this book:

Italic

Used to indicate commands, directory paths, filenames, and URLs.

Constant width

Used to indicate IP and MAC addresses, command-line utilities and tools, interfaces, and flags.

Constant width italic

Used in code examples to show sample text to be replaced with your own values.

Constant width bold

Used to highlight portions of code, typically new additions to old code.

Using Code Examples

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Acknowledgments

There are many people all over the world who have contributed to this book. Without their help and input, it would not be what it is. Big thanks go to Stefan Marzohl, who is a Cisco- and Nortel-certified instructor and the author of Chapter 8. He wrote the chapter for the first edition and made all the updates and additions for the second edition. Many thanks go out to Anja Spittler (Maggy). She spent hours, days, and weeks in our lab setting up SuSE Linux, getting BIND and other services to work, and writing parts of Chapters 9 and 12 in the first edition. I also want to thank the technical editors, who have made this book much better with their invaluable comments, corrections, and clarifications. They were great resources when I was struggling with a topic and needed some answers. The technical reviewers of the first edition were Patrick Grossetete, who works as a product manager for the Internet Technology Division (ITD) at Cisco, and Neil Cashell, who is a great TCP/IP guy at Novell. Thanks also to Brian McGehee, who has been working with IPv6 for many years and has written numerous courses for IPv6. He did the final technical edits of the first edition and added a lot of useful information. I'd like to thank Cisco Switzerland, especially René Räber, both for providing an updated router and access to their technical resources as well as for his continuing support of my work for IPv6. Thanks to the guys at SuSE for providing software and supporting us in getting our SuSE host ready for IPv6, Microsoft for providing software and information about their implementations, Network General for providing Sniffer Pro Software for the trace files, Bob Fink for running the 6Bone web site, Cricket Liu for answering my DNS questions, and Peter Bieringer for running a great Internet resource site and for answering my questions with lightning speed.

There were many additional supporters, writers, and reviewers for the second edition. They include: Jim Bound from HP, CTO of the IPv6 Forum and Chair of the NAv6TF; Latif Ladid, President of the IPv6 Forum; Tim Chown, Department of Electronics and Computer Science at the University of Southampton; and Vijayabhaskar from McAfee. Yurie Rich, John Spence, and Mike Owen from Native6 Inc. in Seattle have provided substantial input into Chapters 1, 5, 6, and 10. Gene Cronk from the Robin Shepherd Group has given substantial input into Chapters 5 and 10, and John Jason Brzozowski, North American IPv6 Task Force and Chair of the Mid-Atlantic IPv6 Task Force, contributed great input into Chapters 1 and 9. Thanks to David B. Green from SRI International for the permission to quote his Enterprise Security Model presentation in Chapter 5 and for reviewing different parts of the book. Thanks to Merike Kaeo, Chief Network Security Architect at Double Shot Security, for all her inputs and comments to Chapter 5. And thanks to Chris Engdahl from Microsoft for his review of Chapter 10. Thanks to Jimmy Ott from Sunny Connection for researching and writing all updates for Chapter 12. David Malone, author of the companion book IPv6 Network Administration, reviewed the whole bookthank you, David, for your great and clarifying comments. A great thank you goes out to all the people who were ready to share their experience with us and have provided case studies. They are Paolo Vieira from the University of Porto, Pierre David from the University of Strasbourg, Cody Christman from NTT Communications, and Flavio Curti and Ueli Heuer from Cyberlink AG in Zurich. Wolfgang Fritsche from IABG Germany and Karim El-Malki from Ericsson AB in Stockholm reviewed and provided input on Chapter 11 about Mobility. Thanks to the people at Checkpoint for providing information and connections, especially Patrik Honegger and Yoni Appel; and thanks also to Jean-Marc Uzé at Juniper for his information and connections. I also want to thank all the people and developers in the international working groups. Without their visionary power, enthusiasm, and tireless work, we would not have IPv6 ready.

A special thank you goes to Jim Sumser, Mike Loukides, and Tatiana Apandi at O'Reilly. Jim Sumser guided me through the whole writing process of the first edition with a lot of enthusiasm, patience, and experience. Thank you, Jim, for being there, and thank you for never hassling me when I was already struggling. You made a difference! Mike and Tatiana, with whom I worked on the second edition, have also been very supportive throughout the whole process. I also want to thank all the other folks at O'Reilly who contributed to this book, especially Tim O'Reilly for making it possible in the first place.

Another very special thank you goes to Hanspeter Bütler, who was my teacher back in school, for teaching me the beauty of the ancient Greek language. His insightful and sensitive way of guiding me into understanding and feeling the richness of old languages laid the foundation for my understanding of language in general, of different cultures and how the differences in viewing the world are expressed in language. I can probably make him partially responsible for my becoming an author. Language is made to communicate, and the more precisely we use our language, the better we can understand and be understood. Without communication, there can be no understanding. On a different level, TCP/IP is the protocol that enables communication in the network and therefore creates the foundation for Internet communication. And the Internet creates the physical foundation for global communication. It offers a great opportunity to communicate, share, and understand globally across all cultures. That is how we should be using it.