VRRP
Router Configuration Guide 411
Context config>router>if>ipv6>vrrp
Description This command associates router IPv6 addresses with the parental IP interface IP addresses and only
applies to the 7750 SR and 7950 XRS.
The backup command has two distinct functions when used in an owner or a non-owner context of
the virtual router instance.
Non-owner virtual router instances actually create a routable IP interface address that is operationally
dependent on the virtual router instance mode (master or backup). The backup command in owner
virtual router instances does not create a routable IP interface address; it simply defines the existing
parental IP interface IP addresses that are advertised by the virtual router instance.
For owner virtual router instances, the backup command defines the IP addresses that are advertised
within VRRP advertisement messages. This communicates the IP addresses that the master is
representing to backup virtual routers receiving the messages. Advertising a correct list is important.
The specified ipv6-addr must be equal to one of the existing parental IP interface IP addresses (link-
local or global) or the backup command will fail.
For non-owner virtual router instances, the backup command actually creates an IP interface IP
address used for routing IP packets and communicating with the system when the access commands
are defined (ping-reply, telnet-reply, and ssh-reply). The specified ipv6-addr must be an IP address
that is within one of the parental IP interface local subnets created with the link-local-address or
address commands. If a local subnet does not exist that includes the specified ipv6-addr or if ipv6-
addr is the same IP address as the parental IP interface IP address, the backup command will fail.
The new interface IP address created with the backup command assumes the mask and parameters of
the corresponding parent IP interface IP address. The ipv6-addr is only active when the virtual router
instance is operating in the master state. For IPv6 VRRP, the parental interface's IP address that is in
the same subnet as the backup address must be manually-configured, non EUI-64 and configured to be
in the preferred state.
When not operating as master, the virtual router instance acts as if it is operationally down. It will not
respond to ARP requests to ipv6-addr, nor will it route packets received with its vrid derived source
MAC address. A non-master virtual router instance always silently discards packets destined to
ipv6-
addr. A single virtual router instance may only have a single virtual router IP address from a given
parental local subnet. Multiple virtual router instances can define a virtual router IP address from the
same local subnet as long as each is a different IP address.
Executing backup multiple times with the same ipv6-addr results in no operation performed and no
error generated. At least one successful backup ipv6-addr command must be executed before the
virtual router instance can enter the operational state.
When operating as (non-owner) master, the default functionality associated with ipv6-addr is ARP
response to ARP requests to ip-addr, routing of packets destined to the virtual router instance source
MAC address and silently discarding packets destined to ipv6-addr. An IPv6 virtual router instance
can enter the operational state only if one of the configured backup address is a link-local address and
the router advertisement of the interface is configured to use the virtual MAC address. Enabling the
non-owner-access parameters selectively allows ping, Telnet and traceroute connectivity to ipv6-addr
when the virtual router instance is operating as master.
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