Cisco's switches support many types of MLS. However, Cisco's current crop of high-end switches, including the 3550, the 4000s, and the 6500, use CEF. A Layer 3 switching engine (sometimes referred to as the main processor) handles the control functions, such as building and maintaining the FIB, and pushes table information down to the line cards or ports, where data ASICs use this information to perform switching decisions in hardware. It's important to point out that CEF is used for hardware switching of unicast frames—not broadcasts.

CEF separates switching into two components: control and data. Control components handle things ...

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