Related Documentation
IGMP and Nonstop Active Routing
Nonstop active routing (NSR) configurations include two Routing Engines that share information so that routing is not interrupted during Routing Engine failover. These NSR configurations include passive support with IGMP in connection with PIM. The master Routing Engine uses IGMP to determine its PIM multicast state, and this IGMP-derived information is replicated on the backup Routing Engine. IGMP on the new master Routing Engine (after failover) relearns the state information quickly through IGMP operation. In the interim, the new master Routing Engine retains the IGMP-derived PIM state as received by the replication process from the old master Routing Engine. This state information times out unless refreshed by IGMP on the new master Routing Engine. No additional IGMP configuration is required.
