Bridging techniques for local area networks

摘要

A communications system includes one or more channels each comprising a plurality of LANs having multiple stations. The LANs of a particular channel are interconnected by a bridge interface, the respective bridge interfaces being connected by a backbone network. Each station is capable of transmitting a data packet including a header having either a 0 or 1 bridge flag, LAN stations being responsive only to data packets having a 0 bridge flag and bridge interfaces only to packets having a 1 bridge flag. Intra-LAN communications are thus effected by data packets having headers with 0 bridge flages while inter-LAN communications are effected by transmitting a packet with a 1 bridge flag from a source station which is coupled to the destination station by the bridge which also changes the bridge flag to 0. A special "broadcast" header is used to effect communications when the LAN or channel of the destination station is unknown.