Fabric path context-based forwarding for virtual nodes

A single-chassis network device 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 plurality of forwarding components that has an egress interface toward a network destination and that is associated with the first virtual routing node, and
• advertise to the second virtual routing node, a message specifying the fabric interface as a next hop for the network destination and a context forwarding table of the second virtual routing node to which to install the fabric interface, and
• wherein the second virtual routing node is configured to, in response to receiving the message specifying the fabric interface, store, to the context forwarding table of the second virtual routing node, the fabric interface as a next hop for the network destination, select, based on the context forwarding table and a context next hop in a first forwarding table pointing to the context forwarding table, the fabric interface for forwarding network packets received by the second virtual routing node and destined for the network destination based on the context forwarding table and a context next hop in a first forwarding table pointing to the context forwarding table, and forward network packets destined for the network destination to the selected fabric interface.

A non-transitory computer-readable storage medium comprising instructions for causing one or more programmable processors 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 a second virtual routing node of the single-chassis network device, a message specifying the fabric interface as a next hop for the network destination and a context forwarding table to which to install the fabric interface;
• in response to receiving the message specifying the fabric interface, store, to the context forwarding table of the second virtual routing node, the fabric interface as a next hop for the network destination;
• select, by the second virtual routing node and based on the context forwarding table and a context next hop in a first forwarding table pointing to the context forwarding table, the fabric interface for forwarding network packets destined for the network destination received by the second virtual routing node;
• and
• forward, by the second virtual routing node, network packets destined for the network destination to the selected fabric interface.