LDP Extension for Inter-Area Label Switched Paths (LSPs)
B. Decraene, JL. Le Roux, I. Minei · 2008
To facilitate the establishment of Label Switched Paths (LSP) that would span multiple IGP areas in a given Autonomous System (AS), this document proposes a new optional label mapping procedure for the Label Distribution Protocol (LDP). This procedure allows the use of a label if the Forwarding Equivalence Class (FEC) Element matches an entry in the routing table (RIB). Matching is defined by an IP longest match search and does not mandate an exact match.