Patent ID: 7940695

Claim:
A system comprising: an ingress label-switching router (LSR) of a first label-switched path (LSP); and an intermediate LSR of the first LSP, wherein the ingress LSR of the first LSP tests connectivity of the first LSP by sending a Multi-Protocol Label Switching (MPLS) echo request packet that includes both a label stack having a label for directing the MPLS echo request packet along the first LSP and a forwarding equivalence class (FEC) stack specifying a FEC identifying the first LSP, and wherein, upon receiving the MPLS echo request packet, the intermediate LSR sends an MPLS echo reply packet to the ingress LSR that includes information that instructs the ingress LSR to modify the FEC stack specified within subsequent MPLS echo request packets to be sent by the ingress LSR for testing connectivity of the first LSP.