Macro Design for IPv6 Lookup Tables

Abstract—Ternary content addressable memory (TCAM) is extensively adopted in network systems. As routing tables become larger, energy consumption and leakage current be-come increasingly important issues in the design of TCAM in nano-scale technologies. This work presents a novel 65 nm en-ergy-efficient TCAM macro design for IPv6 applications. The proposed TCAM employs the concept of architecture and circuit co-design. To achieve an energy-efficient TCAM architecture, a butterfly match-line scheme and a hierarchy search-line scheme are developed to reduce significantly both the search time and power consumption. The match-lines are also implemented using noise-tolerant XOR-based conditional keepers to reduce not only the search time but also the power consumption. To reduce the increasing leakage power in advanced technologies, the proposed TCAM design utilizes two power gating techniques, namely super cut-off power gating and multi-mode data-retention power gating. An energy-efficient 256 144 TCAM macro is implemented using UMC 65 nm CMOS technology, and the experimental results demonstrate a leakage power reduction of 19.3 % and an energy metric of the TCAM macro of 0.165 fJ/bit/search. Index Terms—Butterfly match-line, hierarchy search-line, memory, power gating, TCAM, XOR conditional keeper. I