Transport LSP setup using selected fabric path between virtual nodes

A single-chassis router comprising:

• a plurality of forwarding components;
• a plurality of fabric links coupling respective pairs of the plurality of forwarding components at respective fabric interfaces of the plurality of forwarding components;
• a first virtual routing node configured to forward packets using a first subset of the plurality of forwarding components;
• and a second virtual routing node configured to forward packets using a second subset of the plurality of forwarding components, the second subset distinct from the first subset, wherein the first virtual routing node is configured to:
• select a fabric interface of a forwarding component of the first subset of the plurality of forwarding components that has an egress interface toward a network destination;
• advertise, to the second virtual routing node in a routing protocol message over a single-hop routing protocol session established between the first virtual routing node to the second virtual routing node, the fabric interface as a next hop for the network destination and a label for use in establishing a transport label switched path (LSP);
• and wherein the second virtual routing node is configured to:
• in response to receiving, by the second virtual routing node, the routing protocol message advertising the fabric interface and the label:
• update stored routing information to replace an aggregated fabric interface with the fabric interface as the next hop for the network destination, wherein the aggregated fabric interface is a logical interface associated with a logical link connecting the first virtual routing node and the second virtual routing node, the logical link logically representing multiple fabric links of the plurality of fabric links, wherein the fabric interface is a member interface of the aggregated fabric interface, the fabric interface comprising a physical interface coupling one of the multiple fabric links to the forwarding component of the plurality of forwarding components that has the egress interface toward the network destination;
• compute a path for the transport LSP to include the fabric interface, and
• establish the transport LSP along the computed path by sending a message to the first virtual routing node containing the label, wherein the message comprises one of a Label Distribution Protocol (LDP) label mapping message and a Resource Reservation Protocol with Traffic-Engineering extensions (RSVP-TE) path message.

A non-transitory computer-readable storage medium comprising instructions for causing at least one programmable processor of a single-chassis network device to:

• select, by a first virtual routing node of the single-chassis network device having a plurality of forwarding components and a plurality of fabric links coupling respective pairs of the plurality of forwarding components at respective fabric interfaces of the plurality of forwarding components, a fabric interface of a forwarding component of the plurality of forwarding components that has an egress interface toward a network destination and that is associated with the first virtual routing node;
• advertise, by the first virtual routing node to the second virtual routing node in a routing protocol message over a single-hop routing protocol session established between the first virtual routing node to the second virtual routing node, the fabric interface as a next hop for the network destination and a label for use in establishing a transport label switched path (LSP);
• and
• in response to receiving, by the second virtual routing node, the routing protocol message advertising the fabric interface and the label:
• update, by the second virtual routing node, stored routing information of the second virtual routing node to replace an aggregated fabric interface with the fabric interface as the next hop for the network destination, wherein the aggregated fabric interface is a logical interface associated with a logical link connecting the first virtual routing node and the second virtual routing node, the logical link logically representing multiple fabric links of the plurality of fabric links, wherein the fabric interface is a member interface of the aggregated fabric interface, the fabric interface comprising a physical interface coupling one of the multiple fabric links to the forwarding component of the plurality of forwarding components that has the egress interface toward the network destination,
• compute, by the second virtual routing node, a path for the transport LSP to include the fabric interface, and
• establish, by the second virtual routing node, the transport LSP along the computed path by sending a message to the first virtual routing node containing the label, wherein the message comprises one of a Label Distribution Protocol (LDP) label mapping message and a Resource Reservation Protocol with Traffic-Engineering extensions (RSVP-TE) path message.