System and method for routing traffic through a virtual router-based network switch

A computer-readable medium having stored thereon instructions, which when executed by one or more processors cause the one or more processors to perform a method comprising:

• establishing a packet flow cache having a plurality of entries each identifying one of a plurality of virtual router (VR) flows through a VR-based network device and corresponding forwarding state information;
• receiving a packet at a processing engine of a plurality of processing engines of the VR-based network device;
• determining one or more appropriate packet transformations for application to the packet by an ingress unit of a packet forwarding engine associated with the processing engine by performing flow-based packet classification on the packet;
• using a result of the flow-based packet classification to retrieve an entry of a plurality of entries of the packet flow cache;
• on a packet flow cache hit, determining, based on the corresponding forwarding state information of the retrieved packet flow cache entry, whether to software forward the packet via a processor of the VR-based network device or hardware forward the packet without intervention by the processor via a network interface of the VR-based network device;
• on a packet flow cache miss, identifying the existence of a new VR flow and upon successful allocation of a new entry of the packet flow cache for the new VR flow, forwarding the packet to software on the processor for flow learning.

A virtual router (VR)-based network device comprising:

• a means for establishing a packet flow cache having a plurality of entries each identifying one of a plurality of VR flows through the VR-based network device and corresponding forwarding state information;
• a means for receiving a packet at a processing engine of a plurality of processing engines of the VR-based network device;
• a means for determining one or more appropriate packet transformations for application to the packet by an ingress unit of a packet forwarding engine associated with the processing engine by performing flow-based packet classification on the packet;
• a packet flow cache retrieval means for using a result of the flow-based packet classification to retrieve an entry of a plurality of entries of the packet flow cache;
• a means, responsive to the packet flow cache retrieval means, for determining on a packet flow cache hit and based on the corresponding forwarding state information of the retrieved packet flow cache entry whether to software forward the packet via a processor of the VR-based network device or hardware forward the packet without intervention by the processor via a network interface of the VR-based network device;
• a means, responsive to the packet flow cache retrieval means, for identifying on a packet flow cache miss the existence of a new VR flow and upon successful allocation of a new entry of the packet flow cache for the new VR flow, for forwarding the packet to software on the processor for flow learning.