Interoperability between the Virtual Router Redundancy Protocol and PIM

This document introduces VRRP-aware PIM, a redundancy mechanism for the Protocol Independent Multicast (PIM) to interoperate with the Virtual Router Redundancy Protocol (VRRP). It allows PIM to track VRRP state and to preserve multicast traffic upon failover in a redundant network with virtual routing groups enabled. The mechanism described in this document is based on Cisco IOS software implementation.