Administrator 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:
• debug ipv6 nd ra–guard
• device–role
• hop–limit
• ipv6 nd ra–guard attach–policy
• ipv6 nd ra–guard enable
• ipv6 nd ra–guard policy
• managed-config-flag
• match ra
• mtu
• other–config–flag
• reachable–time
• retrans-time
• router–lifetime
• router–preference maximum
• show config
• show ipv6 nd ra–guard policy
• trusted–port
debug ipv6 nd ra–guard
Enable debugging for IPv6 RA guard snooping information.
Syntax
debug ipv6 nd ra-guard [interface_type slot/port | count value]
Parameters
interface_type
slot/port
Enter the one of the following interfaces and slot/port information:
● For a port channel interface, enter the keywords port-channel then a
number.
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1126 Neighbor Discovery Protocol (NDP)