Flow cache mechanism for performing packet flow lookups in a network device

A network device comprising:

• one or more network interfaces configured to receive a packet of a packet flow, wherein the packet flow is one of a plurality of packet flows processed by the network device;
• a flow cache configured to receive a lookup key associated with the packet flow;
• and
• a Bloom filter configured to process the lookup key,
• wherein the flow cache is further configured to store information about a portion of the plurality of packet flows processed by the network device, determine whether to store information about the packet flow by at least applying a selection criterion to processing of the lookup key by the Bloom filter, determine whether the lookup key is stored in the flow cache, and, when the lookup key is stored in the flow cache, retrieve a stored result associated with the lookup key and output the stored result.

A computer-readable storage medium encoded with instructions for causing one or more programmable processors of a computing device to:

• receive a lookup key associated with a packet flow, wherein the packet flow is one of a plurality of packet flows processed by the computing device, wherein a flow cache of the computing device stores information about a portion of the plurality of packet flows processed by the network device, and wherein the flow cache determines whether to store information about the packet flow based at least in part on applying a selection criterion to processing of the lookup key by a Bloom filter of the network device;
• determine whether the lookup key is stored in the flow cache;
• and
• when the lookup key is stored in the flow cache:
• retrieve a stored result associated with the lookup key;
• and
• output the stored result.