Segmented inter-area P2MP LSP

P2MP LSPs can be segmented at the area boundary. A segmented P2MP LSP consists of an ingress area segment(ingress PE router or ASBR), backbone area segment (Transit ABR), and egress area segment (egress PE routers or ASBRs). Each of the intra-area segments can be carried over provider tunnels such as P2MP RSVP-TE LSP, P2MP mLDP LSP, or ingress replication. Segmentation of inter-area P2MP LSP occurs when the S-PMSI auto-discovery routes are advertised, which triggers the inclusion of a new BGP extended community or inter-area P2MP segmented next-hop extended community in the ingress PE router or ASBR, transit ABR, and egress PE routers or ASBRs.