Clustered address caching system for a network switch

Abstract

A network switch forwards data packets between network stations connected to its input and output ports. Each data packet includes the network address of a destination station. The receiving input port consults an address translation system including a local address translation cache within each input port for caching recently used address-to-port translation information, a set of secondary address translation units each serving a separate cluster of input ports for caching a larger amount of recently used address translation information, and a main address translation unit storing address-to-port translation information for all network stations. An input port not having appropriate translation information in its local cache sends an address translation request to a secondary address translation unit. A secondary address translation unit not having appropriate address translation information to respond to the request, forwards the request to the main address translation unit. The main address translation unit returns the appropriate address translation information to the secondary address translation unit which caches that information and returns it to the requesting input port. The input port caches the information locally and then forwards the packet to the indicated output port.