Network system with shared filtering information

Abstract

A network system comprising a transmission medium coupling a plurality of devices on the network, a plurality of relay devices connected to the transmission medium, each relay device operable to apply filtering on data from the network and transmits frames, each relay device comprising command process division operable to generate and parse commands that include filtering information relating the sharing of filtering information on the network, and when filtering sharing conditions are applied, register filtering information on its own device and apply a protocol to relay to an adjacent device if filtering information sent from an adjacent device through the filtering sharing conditions has a destination address, if a port that received the filtering information from the adjacent matches a relay destination port of the destination address, and if there is only one relay destination port for the destination address, register a receiving port of the filtering information as a destination port, if there is no destination address information in the filtering information sent from the adjacent device through the filtering sharing conditions, and a filtering information sharing protocol division operable to apply a protocol so that filtering information is not relayed to an adjacent device, and a filtering division operable to relay filtering information and frames, or filters discarded information, based on instruction from the filtering information sharing protocol division.