Ultra-low bandwidth intra-network routing method

• US 6,701,375 B1
• Filed: 01/22/1999
• Issued: 03/02/2004
• Est. Priority Date: 01/22/1999
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Siegel, Neil G., Bixler, David C., Walker, W. Clinton
• Primary Examiner(s): Dinh, Dung C.
• Application Number:
  US09/235,544
• Time in Patent Office: 1,866 Days
• Field of Search: 709/232, 709/238, 709/204, 709/233, 709/243, 709/227, 370/254, 370/425, 370/256, 370/352, 370/355
• US Class Current: 709/243
• CPC Class Codes: H04L 45/10 Routing in connection-oriented networks, e.g. X.25 or ATM
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/10 of different types
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding

Abstract

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 (18A) and addressed another (18B) is first sent to a local router (16A), which broadcasts a request for the address of the destination node. Another router (16B) local to the destination host (18B) 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 (16A) associated with the first host computer 18A sets up a switched virtual circuit to the other router (16B), after which the data packet and others following it can be delivered efficiently to the destination host (18B). The second router (16B) 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 (16A, 16B) detects an absence of data packet transmissions along the switched virtual circuit for a selected time, the circuit is deactivated.

Claims

1. A method for establishing a communications path between two host computers in a low-bandwidth intranet, comprising the steps of:

using an auxiliary communication channel to establish a switched virtual circuit between a first router associated with a first host and second router associated with a second host, the first router defines a static route from the first host to the second host via the switched virtual circuit based on a first data packet sent from the first host and addressed to the second host;

establishing a static route from the second host to the first host via the switched virtual circuit based on source address information extracted from the first data packet by the second router;

transmitting data packets in both directions over the switched virtual circuit via the established static routes; and

deactivating the switched virtual circuit when packet transmission activity has ceased for a selected time.

2. A method for establishing a communications path between two host computers in a low-bandwidth intranet, comprising the steps of:

transmitting from a first host in an intranet, a first data packet addressed to a second host in the same intranet;

receiving the first data packet at a first router near the first host;

broadcasting from the first router, over an auxiliary communication channel, a request message identifying the second host;

receiving the request message at a second router, which recognizes the second host identified in the request;

transmitting over the auxiliary communication channel a response to the request message from the second router to the first router, providing a complete address for the second host;

establishing in the first router, upon receiving the response to the request message, a switched virtual circuit between the first and second routers;

transmitting the first data packet from the first router to the second router over the switched virtual circuit; and

transmitting the first data packet from the second router to the second host, to complete delivery of the first data packet.

3. A method as defined in claim 2, and further comprising the steps of:

retrieving the address of the first host from the first data packet upon its arrival at the second router; and

using the address of the first host in the second router, to establish a return path for data packets to be transmitted from the second host to the first host.

4. A method as defined in claim 3, and further comprising the steps of:

transmitting second and additional data packets from the second host to the first host over the switched virtual circuit.

5. A method as defined in claim 4, and further comprising the steps of:

transmitting additional data packets from the first host to the second host over the switched virtual circuit.

6. A method as defined in claim 5, and further comprising the steps of:

sensing in one of the first and second routers that there has not been any transmission of data packets over the switched virtual circuit for some selected time interval; and

deactivating the switched virtual circuit between the first and second hosts when the sensing step determines that the selected time of inactivity has elapsed.

7. A method as defined in claim 2, wherein:

the first and second hosts are attached to different networks, neither of which has an auxiliary communication channel;

the step of transmitting a first data packet to the first router includes transmitting the first data packet through a second network to which the first host and the first router are both connected;

the step of transmitting the first data packet from the second router to the second host includes transmitting the first data packet through a third network to which the second host and the second router are both connected; and

the subsequent steps of transmitting second and additional data packets include transmitting them through the second and third networks.