Label Advertisement Discipline for LDP Forwarding Equivalence Classes (FECs)

Abstract

The label advertising behavior of an LDP speaker for a given Forwarding Equivalence Class (FEC) is governed by the FEC type and not necessarily by the LDP session's negotiated label advertisement mode. This document updates RFC 5036 to make that fact clear. It also updates RFCs 3212, 4447, 5918, 6388, and 7140 by specifying the label advertisement mode for all currently defined LDP FEC types.

Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)

“…A reference has also been added to [RFC7358] to indicate the use of downstream unsolicited mode to distribute PW FEC label bindings, independent of the negotiated label advertisement mode of the LDP session.…”

“…An LDP session must be set up between the pseudowire endpoints. LDP MUST exchange PW FEC label bindings in downstream unsolicited mode, independent of the negotiated label advertisement mode of the LDP session according to the specifications in [RFC7358]. LDP's "liberal label retention" mode SHOULD be used.…”