IGMP snooping support for EVPN-MPLS

You can configure IGMP snooping on devices in an Ethernet VPN (EVPN) over an MPLS network. Enabling IGMP snooping helps to constrain multicast traffic to interested receivers in a broadcast domain. Multicast sources and receivers in the EVPN instance (EVI) can each be single-homed to one provider edge (PE) device or multihomed (in all-active mode only) to multiple PE devices. When IGMP snooping is configured with multihomed receivers, IGMP state information is synchronized among peer PE devices by exchanging BGP EVPN Type 7 (Join Sync Route) and Type 8 (Leave Sync Route) network layer reachability information (NLRI). When PE devices receive multicast traffic from the EVPN core on a multihomed Ethernet segment (ES), only the designated forwarder (DF) PE device forwards the traffic, and the DF forwards the traffic only to interested receivers (selective multicast forwarding) based on IGMP snooping reports and BGP EVPN Type 7 routes. PE devices serving single-homed receivers also use selective multicast forwarding based on IGMP snooping reports to forward the traffic only to interested receivers, conserving network bandwidth. All PE devices perform inclusive multicast forwarding using ingress replication to forward multicast traffic into the EVPN core to reach all remote PE devices. Multicast traffic at Layer 3 is routed between bridge domains or VLANs using IRB interfaces. This feature is supported with multiple EVIs, multicast sources and receivers on the same or different sites, and IGMP snooping in proxy mode only. To enable IGMP snooping on PE devices in an EVPN instance, include the igmp-snooping proxy statement at the [edit routing-instances routing-instance-name protocols] or the [edit routing-instances routing-instance-name bridge-domain bridge-domain-name protocols] hierarchy level. For inter-VLAN multicast forwarding, PIM distributed DR (PIM DDR) mode must be enabled on all participating IRBs. EVPN and IGMP snooping operational mode commands can be used to view information learned from IGMP snooping messages or EVPN Type 7 and Type 8 messages.