Ultra-low bandwidth intra-network routing method

• Main Authors: Walker, W. Clinton, Bixler, David C, Siegel, Neil G
• Format: Patent
• Language: English
• Published: 02.03.2004

This invention relates generally to networks of interconnected computers and, more particularly, to techniques for routing messages or data packets from one node to another in a "locally" located intranet. The nature of the invention first requires a few definitions by way of background. Relatively small networks, perhaps of up to a few hundred nodes and typically located in a single building or group of buildings, are referred to as local area networks (LANs). When the nodes are further apart, the terms "wide area network" or "metropolitan area network" are sometimes used, but the distinction is one of degree and the definitions sometimes overlap. LANs are typically interconnected through switching nodes called bridges and routers, to form a large "internet" of interconnected computer nodes. A technique for saving bandwidth that is otherwise used by the transmission of continual administrative message traffic in an intranet. A data packet originating from one host computer (A) and addressed another (B) is first sent to a local router (A), which broadcasts a request for the address of the destination node. Another router (B) local to the destination host (B) recognizes the destination host in the data packet and supplies a response with the correct address for the destination host. The broadcast request and its response are transmitted over an auxiliary channel, which avoids depleting the bandwidth capacity of the intranet. When the response is received, the local router (A) associated with the first host computer A sets up a switched virtual circuit to the other router (B), after which the data packet and others following it can be delivered efficiently to the destination host (B). The second router (B) uses source address information in the first delivered data packet to set up a return path along the same switched virtual circuit, to allow transmission of data packets in both directions. When one of the routers (A, B) detects an absence of data packet transmissions along the switched virtual circuit for a selected time, the circuit is deactivated.