Multicast Delivery over EVPN with Ingress Replication

[j.a.m.e.s]

Dear All,

With a VXLAN EVPN fabric (based on N9k), I need to deliver a small amount (1Mbit) of multicast video from a server attached to a leaf out through the spine and border-leaf to our classic-ethernet network. PIM is already enabled on the underlay between leaf/spine/borderleaf, but we are using ingress-replication:

interface nve1
  host-reachability protocol bgp
  advertise virtual-rmac
  source-interface loopback2
 member vni 10010
  suppress-arp
  ingress-replication protocol bgp
 [...]
 member vni 103967 associate-vrf
exit
interface Vlan3967
  mtu 9216
  vrf member vf-cam
  no ip redirects
  ip forward
  no ipv6 redirects
  no shutdown
exit

 I thought this would get delivered as broadcast, then at the egress point from the fabric (the border leaf) it would convert to multicast. This isn't happening and there is no PIM mroute entry on the border-leaf. If I want to deliver this traffic, do I really have to roll out TRM?

Many thanks for any insight.

James.

[j.a.m.e.s]

It looks like Ingress Replication (also known as HER or Head-End Replication) will handle multicast as a layer 2 broadcast only. The frames would get sent from Leaf -> BorderLeaf (assuming the VNI is defined on the border-leaf), but at that point even if a PIM join arrives from the external network, the border leaf won't start routing the traffic.

I believe TRM (Tenant Routed Multicast) is needed, which is a pain as it will involve assigning multicast groups for use in the fabric, and there seems to be a few limitations to check through before deploying that (although things are looking better in nx-os v9.3+).