End-to-end traffic engineering label switched paths in seamless MPLS

A network device comprising:

• a physical interface to receive a label request message generated by an access node, wherein the label request message specifies a forwarding equivalence class (FEC) for traffic to be sent by the access node, and data that indicates constraint information for the traffic to be sent by the access node;
• a control unit to establish a first session for a traffic-engineering label distribution protocol with a next hop adjacent to the network device and positioned within a same network as the network device, and to establish a second session for the same traffic-engineering label distribution protocol, wherein the second session has a remote next hop positioned at a border between the network and a second network;
• a traffic-engineering label distribution protocol module to generate a message destined for the remote next hop over the second session for establishing an end-to-end traffic engineered label switched path for the FEC specified in the label request message, wherein the message includes the data indicating the constraint information, which was received by the network device in the label request message from the access node;
• and
• a forwarding component to send the message over the second session.

A computer-readable storage medium comprising instructions for causing a programmable processor to:

• receive a Label Distribution Protocol (LDP) Downstream on Demand (DoD) label request message generated by an access node, wherein the LDP DoD label request message specifies a forwarding equivalence class (FEC) for traffic to be sent by the access node, and data that indicates constraint information for the traffic to be sent by the access node;
• establish a first session for Resource Reservation Protocol with Traffic Engineering extensions (RSVP-TE) with a next hop adjacent to an aggregation node and positioned within a same network as the aggregation node;
• establish a second session for RSVP-TE, wherein the second session has a remote next hop positioned at a border between the network and a second network;
• responsive to receiving the label request message and by the aggregation node, look up the FEC specified by the LDP DoD label request message in BGP labeled unicast (BGP-LU) routing information stored by the aggregation node;
• determine the remote next hop comprising a BGP next hop to which to send the message to reach the FEC based on the lookup in the BGP-LU routing information;
• and
• send a message destined for the BGP next hop over the second session for establishing an end-to-end traffic engineered label switched path for the FEC specified in the label request message, wherein the message includes the data indicating the constraint information, which was received by the aggregation node in the LDP DoD label request message from the access node.