MCS for IGMP snooping synchronizes the join/prune state information from IGMP messages received on the related port/VLANs corresponding to their associated sync-tag. It is enabled as follows.
CLI syntax:
configure
redundancy
multi-chassis
peer ip-address [create]
sync
igmp-snooping
IGMP snooping synchronization is supported wherever IGMP snooping is supported (except in EVPN for VXLAN). See IGMP snooping for VPLS for more information. IGMP snooping synchronization is also only supported for the following active/standby redundancy mechanisms:
MC-LAG
MC-Ring
Single-Active Multihoming (EVPN-MPLS and PBB-EVPN I-VPLS)
Single-Active Multihoming (EVPN-MPLS VPRN and IES routed VPLS)
Configuring an mrouter port under an object that has the synchronization of IGMP snooping states enabled is not recommended. The mrouter port configuration adds a (*,*) entry into the MFIB, which causes all groups (and IGMP messages) to be sent out of the respective object. In addition, the mrouter-port command causes all IGMP messages on that object to be discarded. However, the (*,*) entry is not synchronized by MCS. Consequently, the mrouter port could cause the two MCS peers to be forwarding different sets of multicast streams out of the related object when each is active.