Performance Analysis of TCAMs in Switches

Abstract

The Catalyst 6500 is a modern commercial switch, capable of processing millions of packets per second through the utilization of specialized hardware. One of the main hardware components aiding the switch in performing its task is the Ternary Content Addressable Memory (TCAM). TCAMs update themselves with data relevant to routing and switching based on the traffic flowing through the switch. This enables the switch to forward future packets destined to a location that has already been previously discovered - at a very high speed. The problem is TCAMs have a limited size, and once they reach their capacity, the switch has to rely on software to perform the switching and routing - a much slower process than performing Hardware Switching that utilizes the TCAM. A framework has been developed to analyze the switch’s performance once the TCAM has reached its capacity, as well as measure the penalty associated with a cache miss. This thesis concludes with some recommendations and future work.