The TCP/IP Guide  9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)       9  TCP/IP Internet Layer (OSI Network Layer) Protocols

ICMPv6 Informational Message Options 1 IPv6 ND Overview, History, Motivation and Standards

The new Internet Protocol version 6 (IPv6) represents an evolution of the venerable Internet Protocol. It maintains the same basic operational principles of IPv4, but makes some important modifications, particularly in the area of addressing. In fact, some of the more significant changes in IPv6 are actually not in the IP protocol itself, but in the protocols that support IP. One of the most interesting of these was the creation of an entirely new support protocol for IPv6. It combines several tasks previously performed by other protocols in IPv4, adds some new functions, and makes numerous improvements to the whole package. This new standard is called the IPv6 Neighbor Discovery (ND) protocol.

In this section I describe the new Neighbor Discovery protocol used in IPv6. I begin with an overview of the protocol, discussing its history, the motivation for its creation and the standards that define it. I then describe its operation in general terms, listing the fundamental functions that ND performs, the three groups these functions fit into, and the ICMPv6 message types used to carry them out. I describe the key differences between ND and the way that its functions were carried out in IPv4. I then provide more information on the three functional groups in ND: those that involve discovery of important internetwork information from routers, those that are related to address resolution and neighbor communication between hosts, and finally, router redirection.

ICMPv6 Informational Message Options 1 IPv6 ND Overview, History, Motivation and Standards