EVPN-VXLAN: Automatic synchronization of multicast router interface status among EVPM multihoming peers

Multihoming peer EVPN-VXLAN border leaf (BL) devices that connect to external multicast receivers will now automatically synchronize the multicast router (mrouter) interface status for the EVPN segment identifiers (ESIs) the peer devices share. This feature ensures that multicast traffic reaches external receivers when a non-designated forwarder (NDF) BL peer device receives IGMP or MLD queries from the external PIM domain.

The peer BL devices:

• Use EVPN Type 7 Join Sync routes to communicate the mrouter interface status among their ESI peers.
• Advertise EVPN Type 3 Inclusive Multicast Ethernet Tag (IMET) routes that enable the other EVPN devices to learn how to reach the mrouter interfaces.

This behavior happens by default, so you no longer need to manually configure the multicast-router interface setting on the multihoming peer BL devices.

We support this feature in EVPN-VXLAN bridged overlay (BO) networks with IPv4 or IPv6 underlay peering.