Advertising MPLS labels in OSPF

Historically MPLS label distribution was driven by protocols like LDP, RSVP and LBGP. All of those protocols are session oriented. In order to obtain label binding for a given destination FEC from a given router one needs first to establish an LDP/RSVP/LBGP session with that router. Advertising MPLS labels in IGPs [I-D.gredler-rtgwg-igp-label- advertisement] describes several use cases where utilizing the flooding machinery of link-state protocols for MPLS label distribution allows to obtain the binding without requiring to establish an LDP/RSVP/LBGP session with that router. This document describes the protocol extension to distribute MPLS label bindings by the OSPFv2 and OSPFv3 protocol.