Evaluating an access list can take up additional time, adding to the latency of forwarding packets.
In multilayer switches, however, all of the matching process that ACLs provide is implemented in hardware.
TCAM entries are composed of Value, Mask, and Result (VMR) combinations.
Fields from frame or packet headers are fed into the TCAM, where they are matched against the value and mask pairs to yield a result.
The tables are tailored for Layer 2 switching or MLS, and are kept in very fast memory so that many fields within a frame or packet can be compared in parallel.