A high-speed IP routing lookup scheme with fast updates

Abstract

Most of the existing IP address lookup schemes emphasize the table lookups with little attention to table updates. Updating the routing table often requires a considerable time overhead, especially for gigabit backbone routers. This paper presents a high-speed lookup scheme with a small bounded update time for IP forwarding engines in IP routers. It achieves one IP address lookup per memory access by employing memory access pipelining and updates the table in the time bounded by the IP packet interarrival time on a gigabit link, regardless of the size of the database. The resulting design requires manageably small memories to be implemented using current SRAM technology.