High Speed Routing Lookup IC Design for IPv6

Abstract

With the growth of Internet users and services, the IP address has been exhausted. In order to solve this problem, the short term solution was presented, i.e., CIDR (classless inter-domain routing). The long term solution for insufficient IP addresses is the IPv6 protocol which was defined by IETF (Internet Engineering Task Force). The length of IPv6 address is 128 bits that can avoid the IP address exhaustion. In this paper, a complete hardware for IPv6 routing lookup architecture is proposed. It is composed of routing lookup ASIC and memory set. In our system, the simple hash hardware is used to reduce the lookup time, and the CAM (content addressable memory) is used to solve the collision problem effectively. In our performance analysis, 91.89% routing entries of the routing table can be searched in one memory access, and the worst case about 10% needs two memory accesses. The CAM in the ASIC is used as cache memory with FIFO replacement algorithm. The routing lookup system approaches 213.4Mlps (109.26Gb/s). It is enough to satisfy the high speed link OC-768 (40Gb/s) with 150000 routing entries.