Chapter 2. An IPv6 Refresher

IPv6 represents an evolutionary step for IP. Despite building upon IPv4 and the experience gained operating IPv4 networks, IPv6 has its own idiosyncrasies and unique functionality implementations. For this reason, you should familiarize yourself with the fundamentals of the protocol prior to looking into deploying it. This chapter ushers you into the scope of this book by providing a brief refresher of key IPv6 concepts.

Many aspects of IPv6 set it apart from its predecessor. Some of these aspects are discussed in subsequent chapters from a deployment perspective. This chapter, however, focuses on a subset of IPv6 protocol characteristics that represent the foundation of its operation, as follows:

• IPv6 addressing

• IPv6 packet format

• ICMPv6

• Neighbor Discovery

This chapter particularly emphasizes addressing for a simple reason: It represents one of the most important benefits of IPv6 today. Neighbor Discovery is also discussed at length to clarify the link operation of IPv6.

Rather than repeating the information readily available in many books dedicated to describing the IPv6 protocols, this book focuses on reviewing the deltas from IPv4 and their impact on deployment. The following books are recommended for technology overviews: Cisco Self-Study: Implementing Cisco IPv6 Networks (IPv6) by R. Desmeules, and IPv6: The New Internet Protocol by C. Huitema.