IETF RFC 7524 PDF

This document describes procedures for building inter-area point-tomultipoint (P2MP) segmented service label switched paths (LSPs) by partitioning such LSPs into intra-area segments and using BGP as the inter-area routing and Label Distribution Protocol (LDP). Within each IGP area, the intra-area segments are either carried over intraarea P2MP LSPs, using P2MP LSP hierarchy, or instantiated using ingress replication. The intra-area P2MP LSPs may be signaled using P2MP RSVP-TE or P2MP multipoint LDP (mLDP). If ingress replication is used within an IGP area, then (multipoint-to-point) LDP LSPs or (point-to-point) RSVP-TE LSPs may be used in the IGP area. The applications/services that use such inter-area service LSPs may be BGP Multicast VPN, Virtual Private LAN Service (VPLS) multicast, or global table multicast over MPLS.