Class-based traffic engineering in an IP network

A method comprising:

• sending, by a network device of a plurality of network devices of an Internet Protocol (IP) network, a capability message to an egress device of the IP network, wherein the capability message specifies a capability to compute a constrained path, wherein the capability message comprises path computation information including an identifier of a path computation algorithm to be used by the network device to identify the constrained path to compute;
• receiving, by the network device, a reachability message requesting establishment of a constrained path to the egress network device, wherein the reachability message comprises a destination IP prefix address of the egress network device and the identifier of the path computation algorithm from the path computation information to be used by the network device to compute the constrained path to reach the egress network device;
• computing, by the network device, the constrained path using the identifier of the path computation algorithm included in the reachability message;
• and
• configuring, by the network device, the network device to forward traffic on the constrained path toward the egress network device.

A network device comprising:

• a memory;
• one or more processors coupled to the memory, wherein the one or more processors are configured to:
• receive a capability message from one or more network devices of a plurality of network devices of an Internet Protocol (IP) network specifying a capability to compute a constrained path to an egress network device of the IP network, wherein the capability message comprises path computation information including an identifier of a path computation algorithm to be used by the one or more of the plurality of network devices to identify the constrained path to compute;
• generate a reachability message requesting establishment of the constrained path to the egress network device, wherein the reachability message comprises a destination IP prefix address of the egress network device and the identifier of the path computation algorithm from the path computation information received from the capability message;
• and
• send, to the plurality of network devices of the IP network, the reachability message to request that the plurality of network devices compute the constrained path to reach the egress network device.