In this task, when you enter the standby
ipv6 command, a link-local address is generated from the link-local prefix, and a modified EUI-64 format interface identifier
is generated in which the EUI-64 interface identifier is created from the relevant HSRP virtual MAC address.
A link-local address is an IPv6 unicast address that can be automatically configured on any interface using the link-local
prefix FE80::/10 (1111 1110 10) and the interface identifier in the modified EUI-64 format. Link-local addresses are used
in the stateless autoconfiguration process. Nodes on a local link can use link-local addresses to communicate; the nodes do
not need site-local or globally unique addresses to communicate.
In IPv6, a device on the link advertises in RA messages any site-local and global prefixes, and its willingness to function
as a default device for the link. RA messages are sent periodically and in response to router solicitation messages, which
are sent by hosts at system startup.
A node on the link can automatically configure site-local and global IPv6 addresses by appending its interface identifier
(64 bits) to the prefixes (64 bits) included in the RA messages. The resulting 128-bit IPv6 addresses configured by the node
are then subjected to duplicate address detection to ensure their uniqueness on the link. If the prefixes advertised in the
RA messages are globally unique, then the IPv6 addresses configured by the node are also guaranteed to be globally unique.
Router solicitation messages, which have a value of 133 in the Type field of the ICMP packet header, are sent by hosts at
system startup so that the host can immediately autoconfigure without needing to wait for the next scheduled RA message.
To enabling and verifying an HSRP group for IPv6, perform this procedure: