Why would you need a whole book about Internet protocol version 6 (IPv6)? It’s just a later release of Internet protocol version 4 (IPv4), with address fields containing 128 bits instead of 32 bits.

Actually, there’s a lot more to IPv6 than that. The author devotes some 340 pages to detailing its characteristics and, to a lesser extent, its capabilities. She is currently CEO of a consulting company in Switzerland, and has spent some time as an instructor. Her expertise is in directory services and protocol analysis, so she is obviously well qualified to write a book like this.

The book begins with a brief history of how IPv6 was developed in order to work around the progressive address-space exhaustion that has plagued IPv4 in recent years. Several proposals were developed along the way, and some details of the working parties and requests for comment (RFC) documents associated with them are given for readers who wish to pursue them. A summary of the extensions in functionality offered by IPv6 is provided, and there are some paragraphs on transitional considerations.

IPv6 is still in development, but there are already some global networks in which it is used. The best known of these is probably the 6Bone network; the author offers some details in relation to this, and mentions several other IPv6 networks.

The structure of the IPv6 protocol is covered in chapter 2. It contains some good packet diagrams and trace file screen shots, which make it somewhat easier to understand than the raw RFC documents from which it is derived. There are also some informative paragraphs on the use of extension headers as a mechanism for conveying hop-by-hop, routing, and other options in a manner that simplifies handling.

IPv6 address structures and types differ from those used in IPv4, and this is explained (with more packet diagrams and screen shots) in chapter 3. In a similar vein, the extended functionality found in Internet control message protocol (ICMP) is covered in chapter 4; one of the most important capabilities in this regard is that of autoconfiguration.

Security, quality of service, and networking issues are dealt with in chapters 5 through 7. While not exciting, these are issues that any system administrator or network engineer absolutely has to know about.

Chapter 8, “Routing Protocols,” occupies more than 70 pages, and provides comprehensive details of two interior gateway protocols (IGPs) and one exterior gateway protocol (EGP). Those in the former category are respectively routing information protocol next-generation (RIPng) and open shortest path first (OSPF) for IPv6. The other is border gateway protocol version 4 (BGP-4). Some useful diagrams are included to illustrate route poisoning and other concepts. Brief overviews are included for two emerging protocols: Integrated IS-IS and Cisco EIGRPv6.

Some changes are required in upper-layer protocols to accommodate the extended functionality of IPv6, and these are discussed in chapter 9. Some of the more obvious examples are dynamic host configuration protocol (DHCP), domain name system (DNS), and service location protocol (SLP); all of these must be able to return 128-bit addresses. A less obvious candidate is file transfer protocol (FTP). The author provides some good screen shots illustrating DNS and other operations performed on SuSE Linux and Windows 2000 machines.

IPv6 and IPv4 will coexist for many years. The techniques that have been developed to make that coexistence possible are described in chapter 10, “Interoperability.” Readers are shown how to decide between using dual-stack, tunneling and network address translation (NAT) mechanisms.

The final chapter, “Getting Your Hands Dirty,” lists some sources for Solaris, Linux, Windows, and Cisco IPv6 stacks and associated utilities. Some configuration and test screen shots are included. Lists of RFCs and IPv6 resources are included in the appendices at the end of the book.

There is no way I can pretend that I found this book interesting! But I plan on being around for a few years yet, and I will need a good IPv6 reference on my bookshelf. I couldn’t find anything better.