Content-addressable memory

CAM is short for Content adressable memory.

When reading usual ram, one supplys an adress and gets data. on CAM, one supplys data and gets an adress.

CAM does a quick search on it's memort to find the matching the adress that matches the data. the search is very fast - sometimes as fast as reading regular ram.

a usual use for CAM by a router is mapping MAC adresses (48 bit long) to IP adresses (32 bit long). to use a usual ram, one needs 256 Terra (2^48) adresses, each 32 bits wide. this will map every mac adress possible to an ip adress. this is really not necessery as there are only 2^32 ip adresses possible and usually not that much seen by a single router. a CAM is the better way to do it, as it can store only a subset of the mac-ip map in a smaller memory