IPv4 and IPv6 multicast routing is supported in a R-VPLS service through its IP interface when the source of the multicast stream is on one side of its IP interface and the receivers are on either side of the IP interface. For example, the source for multicast stream G1 could be on the IP side sending to receivers on both other regular IP interfaces and the VPLS of the R-VPLS service, while the source for group G2 could be on the VPLS side sending to receivers on both the VPLS and IP side of the R-VPLS service.
IPv4 and IPv6 multicast routing is not supported with Multicast VLAN Registration functions or the configuration of a video interface within the associated VPLS service. It is also not supported in a routed I-VPLS service, or for IPv6 multicast in BGP EVPN-MPLS routed VPLS services. Forwarding IPv4 or IPv6 multicast traffic from the R-VPLS IP interface into its VPLS service on a P2MP LSP is not supported.
The IP interface of a R-VPLS supports the configuration of both PIM and IGMP for IPv4 multicast and for both PIM and MLD for IPv6 multicast.
To forward IPv4/IPv6 multicast traffic from the VPLS side of the R-VPLS service to the IP side, the forward-ipv4-multicast-to-ip-int and/or forward-ipv6-multicast-to-ip-int commands must be configured as follows:
configure
service
vpls <service-id>
allow-ip-int-bind
forward-ipv4-multicast-to-ip-int
forward-ipv6-multicast-to-ip-int
exit
exit
exit
exit
Enabling IGMP snooping or MLD snooping in the VPLS service is optional, where supported. If IGMP/MLD snooping is enabled, IGMP/MLD must be enabled on the R-VPLS IP interface in order for multicast traffic to be sent into, or received from, the VPLS service. IPv6 multicast uses MAC-based forwarding; see MAC-based IPv6 multicast forwarding for more information.
If both IGMP/MLD and PIM for IPv4/IPv6 are configured on the R-VPLS IP interface in a redundant PE topology, the associated IP interface on one of the PEs must be configured as both the PIM designated router and the IGMP/MLD querier. This ensures that the multicast traffic is sent into the VPLS service, as IGMP/MLD joins are only propagated to the IP interface if it is the IGMP/MLD querier. An alternative to this is to configure the R-VPLS IP interface in the VPLS service as an mrouter port, as follows:
configure
service
vpls <service-id>
allow-ip-int-bind
igmp-snooping
mrouter-port
mld-snooping
mrouter-port
exit
exit
exit
exit
This configuration achieves a faster failover in scenarios with redundant routers where multicast traffic is sent to systems on the VPLS side of their R-VPLS services and IGMP/MLD snooping is enabled in the VPLS service. If the active router fails, the remaining router does not have to wait until it sends an IGMP/MLD query into the VPLS service before it starts receiving IGMP/MLD joins and starts sending the multicast traffic into the VPLS service. When the mrouter port is configured as above, all IGMP/MLD joins (and multicast traffic) are sent to the VPLS service IP interface.
IGMP/MLD snooping should only be enabled when systems, as opposed to PIM routers, are connected to the VPLS service. If IGMP/MLD snooping is enabled when the VPLS service is used for transit traffic for connected PIM routers, the IGMP/MLD snooping would prevent multicast traffic being forwarded between the PIM routers (as PIM snooping is not supported). A workaround would be to configure the VPLS SAPs and spoke-SDPs (and the R-VPLS IP interface) to which the PIM routers are connected as mrouter ports.
If IMPM is enabled on an FP on which there is a R-VPLS service with forward-ipv4-multicast-to-ip-int or forward-ipv6-multicast-to-ip-int configured, the IPv4/IPv6 multicast traffic received in the VPLS service that is forwarded through the IP interface is IMPM-managed even without IGMP/MLD snooping being enabled. This does not apply to traffic that is only flooded within the VPLS service.
When IPv4/IPv6 multicast traffic is forwarded from a VPLS SAP through the R-VPLS IP interface, the packet count is doubled in the following statistics to represent both the VPLS and IP replication (this reflects the capacity used for this traffic on the ingress queues, which is subject to any configured rates and IMPM capacity management):
Offered queue statistics
IMPM managed statistics
IMPM unmanaged statistics for policed traffic
IPv4 or IPv6 multicast traffic entering the IP side of the R-VPLS service and exiting over a multi-port LAG on the VPLS side of the service is sent on a single link of that egress LAG, specifically the link used for all broadcast, unknown, and multicast traffic.
An example of IPv4/IPv6 multicast in a R-VPLS service is shown in Figure 1. There are two R-VPLS IP interfaces connected to an IES service with the upper interface connected to a VPLS service in which there is a PIM router and the lower interface connected to a VPLS service in which there is a system using IGMP/MLD.
The IPv4/IPv6 multicast traffic entering the IES/VPRN service through the regular IP interface is replicated to both the other regular IP interface and the two R-VPLS interfaces if PIM/IGMP/MLD joins have been received on the respective IP interfaces. This traffic is flooded into both VPLS services unless IGMP/MLD snooping is enabled in the lower VPLS service, in which case it is only sent to the system originating the IGMP/MLD join.
The IPv4/IPv6 multicast traffic entering the upper VPLS service from the connected PIM router is flooded in that VPLS service and, if related joins have been received, forwarded to the regular IP interfaces in the IES/VPRN. It is also be forwarded to the lower VPLS service if an IGMP/MLD join is received on its IP interface, and is flooded in that VPLS service unless IGMP/MLD snooping is enabled.
The IPv4/IPv6 multicast traffic entering the lower VPLS service from the connected system is flooded in that VPLS service, unless IGMP/MLD snooping is enabled, in which case it is only forwarded to SAPs, spoke-SDPs, or the R-VPLS IP interface if joins have been received on them. It is forwarded to the regular IP interfaces in the IES/VPRN service if related joins have been received on those interfaces, and it is also forwarded to the upper VPLS service if a PIM IPv4/IPv6 join is received on its IP interface, this being flooded in that VPLS service.