A hybrid scheme for routing lookup with fast updates based on TCAMs

The exponential growth of routing tables in routers results in the exhaustion of IPv4 address. The urgent demand of high speed of routing lookup makes the Ternary CAM (TCAM), which needs only one cycle in each parallel lookup, a state-in-art hardware for Internet Protocol (IP) lookup and packet forwarding. However, the performance of TCAM is cut down due to too much update time. In this paper, we proposed a hybrid scheme for routing lookup with fast updates based on TCAMs. In our scheme, about 95% prefixes to be updated need no more than one movement. In the worst case, delete a prefix needs only 2 movements and insert a prefix needs 5 movements. The proposed scheme could fit different routing tables.