Operating mpls label switched paths and mpls pseudowire in loopback mode

An apparatus comprising:

• a network interface configured to communicate with a tail-end label switching router (LSR) and one or more intermediate LSRs located along a circuit;
• a processor coupled to the network interface and configured to execute one or more software processes;
• and
• a memory configured to store a software process executable by the processor, the software process when executed operable to:
• cause the network interface to transmit along the circuit a packet including a loopback request, the packet including the loopback request having a particular time-to-live (TTL) value configured to expire at a particular intermediate LSR at which loopback is to occur,
• use the circuit in a loopback mode,
• cause the network interface to transmit along the circuit a packet including a cease loopback request,
• cease to use the circuit in the loopback mode.

An apparatus comprising:

• means locking a circuit, that extends between a head-end label switching router (LSR) and a tail-end LSR and traverses one or more intermediate LSRs;
• means for transmitting along the circuit a packet including a loopback request, the packet including the loopback request having a particular time-to-live (TTL) value configured to expire at a particular intermediate LSR at which loopback is to occur;
• means for transmitting along the circuit a packet including a cease loopback request, wherein the packet including the cease loopback request has the particular TTL value configured to expire at the particular intermediate LSR;
• and means for unlocking the circuit.