An efficient parallel TCAM scheme for the forwarding engine of the next-generation router

Abstract

Ternary Content-Addressable Memory (TCAM) is a popular hardware device for fast IP address lookup. High link transmission speed of Internet backbone demands more powerful IP address lookup engine. Restricted by the memory access speed, the lookup engine for next-generation routers demands exploiting parallelism among multiple TCAM chips. However, most existing schemes improve lookup performance and reduce power consumption but ignore the update efficiency. In this paper, we propose a crossed address range division and shared caching scheme. We improve the update efficiency significantly by buddy update method while keep low power dissipation by decreasing the number of the triggered TCAMs access in each lookup operation. The lookup throughput is ultra high through adaptive load balance. Our simulation results show that the proposed scheme can achieve an average lookup speedup factor greater than 11 with 12 TCAM chips, on the cost of 10% more memory space and an additional cache chip.