TABLE OF CONTENTS One area in which IPv4 networking is made more complicated is in locating servers, routers, configuration data, and generally in making it possible for nodes to determine what other nodes are nearby (on the same link) and what nodes are remote (off-link). Neighbor Discovery ( ND) for IPv6 is defined in RFC 2461, Neighbor Discovery for IPv6, and it provides an important tool that not only simplifies network administration and management but also enables a much greater degree of scaling in IPv6 network size.
This chapter compares how ND is specified and implemented in IPv4 and IPv6, followed by a discussion of some of the roles that ND fulfills for IPv6. The rest of the chapter outlines how ND works, with some example ND messages and protocol interactions.
As noted in the abstract of RFC 2461, IPv6 nodes on the same link use Neighbor Discovery to discover each other s presence, to determine each other s link layer addresses, to find routers and to maintain reachability information about the paths to active neighbors. Five types of ICMPv6 messages to be used in neighbor discovery are defined in RFC 2461, including a pair of messages for router solicitation and router advertisement, a pair for neighbor solicitation and advertisement, and a redirect message.
By defining neighbor discovery functions in terms of ICMPv6 messages, additional protocols (such as ARP) are unnecessary and without a mechanism for doing broadcast (as in IPv4), those protocols would not work anyway. As a...
