Hybrid Partitioned SRAM-Based Ternary Content Addressable Memory

Although content addressable memory (CAM) provides fast search operation; however, CAM has disadvantages like low bit density and high cost per bit. This paper presents a novel memory architecture called hybrid partitioned static random access memory-based ternary content addressable memory (HP SRAM-based TCAM), which emulates TCAM functionality with conventional SRAM, thereby eliminating the inherited disadvantages of conventional TCAMs. HP SRAM-based TCAM logically dissects conventional TCAM table in a hybrid way (column-wise and row-wise) into TCAM sub-tables, which are then processed to be mapped to their corresponding SRAM memory units. Search operation in HP SRAM-based TCAM involves two SRAM accesses followed by a logical ANDing operation. To validate and justify our approach, 512 × 36 HP SRAM-based TCAM has been implemented in Xilinx Virtex-5 field programmable gate array (FPGA) and designed using 65-nm CMOS technology. Implementation in FPGA is advantageous and a beauty of our proposed TCAM because classical TCAMs cannot be implemented in FPGA. After a thorough analysis, we have concluded that energy/bit/search of the proposed TCAM is 85.72 fJ.

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