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
• device-role
• hop-limit
• ipv6 neighbor
• managed-config-flag
• match ra
• mtu
• other-config-flag
• reachable-time
• retrans-time
• router-lifetime
• router-preference maximum
• show config
• show ipv6 neighbors
clear ipv6 neighbors
Delete all entries in the IPv6 neighbor discovery cache or neighbors of a specific interface. Static entries are not removed using
this command.
C9000 Series
Syntax
clear ipv6 neighbors [ipv6 address] | interface interface | vrf vrf name]
Parameters
ipv6-address Enter the IPv6 address of the neighbor in the x:x:x:x::x format to remove a specific
IPv6 neighbor.
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1074 Neighbor Discovery Protocol (NDP)