Unlike 2547 VPN unicast, which uses point-to-point LSPs, NG MVPN uses point-to-multipoint (P2MP) LSPs. As shown in A P2MP LSP with two destinations, a P2MP LSP is a TE tunnel with a single source and multiple destinations.

Figure 1. A P2MP LSP with two destinations

A P2MP LSP is composed of two or more point-to-point LSPs, called subLSPs, which are formed between the ingress and egress PEs to form the P2MP LSP. Each subLSP is a separate RSVP session that is signaled end-to-end.

The P2MP in Figure 4 is composed of two subLSPs:

  • PEa -> P -> PEb

  • PEa -> P -> PEc