Link discovery and verification procedure using loopback

An apparatus for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said apparatus comprising:

• a port having an input and an output, said input and output comprising optical interfaces;
• a line termination unit capable of, in accordance with a protocol, interpreting data received via said port input and formatting data to be transmitted via said port output;
• and
• a processor that connects said line termination unit to said port, monitors data received at said port at said first node to check for a match to data transmitted at said first port, and if said received data matches said transmitted data, determines that said port at said first node is connected to an internally looped-back port at said second node, stores an indication of connectivity between said first node and said second node, and removes said looped back condition after verifying a connection between said first node and said second node, said data traveling entirely in optical form between said first node and said second node and through said looped-back port.

An apparatus for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said apparatus comprising:

• means for looping back a port of said first node by internally connecting an input of said port to an output of said port via an all-optical connection within said first node;
• and
• means for notifying said second node of a looped back condition of said port to advance a procedure that verifies connectivity between said first node and said second node by employing a looped back condition of said port;
• and
• means for removing said looped back condition after verifying a connection between said first node and said second node.