Multicast over Fabric Connect cannot connect to a PIM router that is external to the SPB network. When a receiver joins the SPB network for a specific group, the receiver must receive multicast streams in the neighboring multicast domains (PIM network). Similarly, a receiver in the neighboring multicast domain (PIM network) must receive multicast streams from sources in the SPB network. SPB-PIM Gateway (SPB-PIM GW) provides multicast inter-domain communication between an SPB network and a PIM network. SPB-PIM GW accomplishes this inter-domain communication across a special gateway VLAN. The gateway VLAN communicates with the PIM network through a subset of the full protocol messaging required for RFC 4601 compliance of a PIM interface, and translates the PIM network requirements into SPB language and vice versa.
One or more SPB domains can share streams with one or more PIM domains.
SPB-PIM GW can connect two independent SPB domains. The independent SPB domains connected by SPB-PIM GW share a subset of multicast streams without a PIM network in between.
SPB-PIM GW is supported in the GRT and in VRFs.
In a Multicast over Fabric Connect environment with SPB-PIM GW, the SPB network connects sources and receivers from one or more PIM networks. The multicast traffic is then delivered across the domain boundaries through a path that transports the multicast traffic.
Multicast over Fabric Connect with SPB-PIM GW functionality consists of SPB nodes, which act as SPB-PIM Controller nodes and SPB-PIM Gateway nodes. The SPB Controller uses the Multicast Source Discovery Protocol (MSDP) to discover foreign sources.
The following figure shows the Multicast over Fabric Connect environment with SPB-PIM GW.
