A High-Speed Range-Matching TCAM for Storage-Efficient Packet Classification
Young-Deok Kim, Hyun-Seok Ahn, Suhwan Kim, Deog‐Kyoon Jeong · IEEE Transactions on Circuits and Systems I Regular Papers · 2008
A critical issue in the use of TCAMs for packet classification is how to efficiently represent rules with ranges, known as range matching. A range-matching ternary content addressable memory (RM-TCAM) including a highly functional range-matching cell (RMC) is presented in this paper. By offering various range operators, the RM-TCAM can reduce storage expansion ratio from 4.21 to 1.01 compared with conventional TCAMs, under real-world packet classification rule sets, which results in reduced power consumption and die area. A new pre-discharging match-line scheme is used to realize high-speed searching in a dynamic match-line structure. An additional charge-recycling driver further reduces the power consumption of search lines. Simulation results of a 256times64-bit range-matching TCAM, when implemented in the 0.13-mum CMOS technology, achieves a 1.99-ns search time with an energy efficiency of 1.26 fJ/bit/search. While a TCAM including range encoding approach requires an additional SRAM or DRAM, the RM-TCAM can improve storage efficiency without any extra components as well as reduce the die area.