What is the difference between CAM and TCAM in networking?

 

TCAM is a special version of CAM. The main characteristic of both CAM and TCAM is that it is able to search all its entries in parallel. So the content search takes only one clock cycle. Though speed is high, it is expensive.

Main difference between CAM and TCAM

i) CAM requires an exact match on the key stored in its table whereas TCAM allows partial match.

In TCAM data are stored and queried using 0, 1 and X unlike 0 and 1 in case of CAM. X can be referred don’t care or wild card state. The name Ternary comes from the use of three states.

ii) From usage point of view in networking devices:

CAM is used in Ethernet switch (MAC table look up )whereas in TCAM is used in router (router prefix look up).