Method and apparatus for improving CAM learn throughput using a cache

摘要

An apparatus and method of using a cache to improve a learn rate for a content-addressable memory (“CAM”) are disclosed. A network device such as a router or a switch, in one embodiment, includes a key generator, a searching circuit, and a key cache, wherein the key generator is capable of generating a first lookup key in response to a first packet. The searching circuit is configured to search the content of the CAM to match the first lookup key. If the first lookup key is not found in the CAM, the key cache stores the first lookup key in response to a first miss.

主权项

1. A network device comprising:
a key generator capable of generating a first lookup key in response to a first packet; a searching circuit coupled to the key generator and configured to search content of a content-addressable memory (“CAM”) to match the first lookup key; a key cache coupled to the searching circuit and capable of storing the first lookup key in response to a first miss generated by the searching circuit when the content of the CAM does not match with the first lookup key; and a comparing circuit coupled to the key cache and configured to compare the first lookup key stored in the key cache with a second lookup key, which is generated in accordance with a second packet in response to a second miss.