The VRRP Aware PIM feature enables PIM to track the state of a VRRP instance and to identify whether the associated VRRP interface is the master. PIM uses an operational group parameter (oper-group group-name) to monitor the state of VRRP. One operational group can be created for IPv4, and another for IPv6. When VRRP is the MR, the operational group is up; for all other VRRP states, the operational group is down. A VRRP instance can only be associated with one operational group, and an operational group can have one or more associated VRRP instances. This feature is supported on base router, IES, and VPRN interfaces.
If the monitored interface is the VRRP MR, PIM becomes the DR by setting its priority to the configured oper-group-active-priority value. For the router to become the DR, the correct priorities must be configured so that the oper-group-active-priority is the highest priority on the IP interface.
If a PIM router is the DR and then receives an indication from VRRP that the interface is no longer the VRRP MR, PIM relinquishes the DR role by setting its priority back to the default or configured priority value.
If the configured VRRP instance or oper-group is not configured, PIM operates as normal with the default or configured priority value, and does not set its priority to oper-group-active-priority. A change in the operational group status is independent of the address family; IPv4 and IPv6 priorities are configured independently of each other. Two operational groups are supported per PIM interface, one for IPv4 and one for IPv6.