Users Guide

Neighbor Discovery Protocol (NDP)

The neighbor discovery protocol for IPv6 is defined in RFC 2461 as part of the Stateless Address

Autoconfiguration protocol. It replaces the Address Resolution Protocol used with IPv4. NDP defines

mechanisms for solving the following problems:

• Router discovery — hosts can locate routers residing on a link

• Prefix discovery — hosts can discover address prefixes for the link

• Parameter discovery

• Address autoconfiguration — configuration of addresses for an interface

• Address resolution — mapping from IP address to link-layer address

• Next-hop determination

• Neighbor unreachability detection (NUD) — determine that a neighbor is no longer reachable on the

link.

• Duplicate address detection (DAD) — allow a node to check whether a proposed address is already in

use.

• Redirect — the router can inform a node about a better first-hop.

NDP uses the following five ICMPv6 packet types in its implementation:

• Router Solicitation

• Router Advertisement

• Neighbor Solicitation

• Neighbor Advertisement

• Redirect

Topics:

• clear ipv6 neighbors

• ipv6 neighbor

• show ipv6 neighbors

• IPv6 Router Advertisement (RA) Guard

Neighbor Discovery Protocol (NDP) 1319