Bidirectional Forwarding Detection (BFD) Reverse Path for MPLS Label Switched Paths (LSPs)

Bidirectional Forwarding Detection (BFD) is expected to be able to monitor a wide variety of encapsulations of paths between systems. When a BFD session monitors an explicitly routed unidirectional path, there may be a need to direct the egress BFD peer to use a specific path for the reverse direction of the BFD session. This document describes an extension to the MPLS Label Switched Path (LSP) echo request that allows a BFD system to request that the remote BFD peer transmit BFD control packets over the specified LSP.