Patent attributes
This invention first presents SRAM based pipeline IP lookup architectures including an SRAM based systolic array architecture that utilizes multi-pipeline parallelism idea and elaborates on it as the base architecture highlighting its advantages. In this base architecture a multitude of intersecting and different length pipelines are constructed on a two dimensional array of processing elements in a circular fashion. The architecture supports the use of any type of prefix tree instead of conventional binary prefix tree. The invention secondly proposes a novel use of an alternative and more advantageous prefix tree based on binomial spanning tree to achieve a substantial performance increase. The new approach, enhanced with other extensions including four-side input and three-pointer implementations, considerably increases the parallelism and search capability of the base architecture and provides a much higher throughput than all existing IP lookup approaches making, for example, a 7 Tbps router IP lookup front end speed possible. Although theoretical worst-case lookup delay in this systolic array structure is high, the average delay is quite low, large delays being observed only rarely. The structure in its new form is scalable in terms of processing elements and is also well suited for the IPv6 addressing scheme.
