Method and system for routing communications among computer networks

• US 7,042,834 B1
• Filed: 07/28/2000
• Issued: 05/09/2006
• Est. Priority Date: 07/28/2000
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Savage, Donnie V.
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): Hyun, Soon D.
• Application Number:
  US09/627,248
• Time in Patent Office: 2,111 Days
• Field of Search: 370/216, 370/242, 370/244, 370/250, 370/254, 370/390, 370/255, 370/395.3, 709/220, 709/221, 709/238, 709/239, 709/242
• US Class Current: 370/218
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

A method and system for determining route redistribution are disclosed. The method generally comprises receiving an information packet from a neighbor source. The information packet identifies the source as a stub router and specifies route types that the source will advertise. Upon receiving notice of a failed link within the network, query packets are sent only to neighboring devices that have not been identified as stub routers to request route information.

Claims

1. A method for determining route redistribution at a device within a network, the method comprising:

receiving an information packet from a neighbor source, the information packet identifying the neighbor source as a stub router and specifying route types that the neighbor source will advertise, wherein the stub router is identified as a router to which query generation is suppressed; and

upon receiving notice of a failed link within the network, sending query packets requesting route information only to neighboring devices that have not been identified as stub routers.

2. The method of claim 1 wherein receiving the information packet comprises receiving a hello packet containing peer information.

3. The method of claim 1 wherein the device and stub router are configured for EIGRP.

4. The method of claim 1 wherein the network has a hub and spoke arrangement and the device is a hub router and the stub router is a spoke.

5. The method of claim 1 wherein the network includes a dual homed host.

6. The method of claim 1 wherein the route types that the source will advertise is connected routes.

7. The method of claim 1 wherein the route types that the source will advertise is summary routes.

8. The method of claim 1 wherein the route types that the source will advertise is static routes.

9. The method of claim 1 wherein the device and the neighboring devices have point-to-point links.

10. The method of claim 1 wherein the device and the neighboring devices have multipoint links.

11. The method of claim 10 wherein only one neighboring device is a stub router.

12. The method of claim 10 wherein multiple neighboring devices are stub routers.

13. The method of claim 1 wherein the device is a router.

14. A method for reducing query generation for route redistribution within a network, the method comprising:

receiving information at a router from a source identifying the router as a stub router;

sending an information packet from the stub router to neighboring devices, the information packet identifying the source as a stub router and specifying route types that the stub router will advertise; and

upon receiving a query for route information other than the route types type specified in the information packet, sending a response packet with routes identified as inaccessible.

15. The method of claim 14 wherein the network has a hub and spoke arrangement and the stub router is a spoke.

16. The method of claim 14 wherein the stub router is in communication with a dual homed device.

17. The method of claim 14 wherein sending the information packet comprises transmitting a hello packet.

18. The method of claim 14 wherein the stub router is configured for EIGRP.

19. A computer program product for determining route redistribution at a device within a network, the product comprising:

code that utilizes an information packet received from a neighbor source, the information packet identifying the neighbor source as a stub router and specifying route types that the neighbor source will advertise, wherein the stub router is identified as a router to which query generation is suppressed;

code that prepares query packets requesting route information and directs the query packets to be sent only to neighboring devices that have not been identified as stub routers upon receiving notice of a failed connection; and

a computer-readable storage medium for storing the codes.

20. The computer program product of claim 19 wherein the computer readable medium is selected from the group consisting of CD-ROM, floppy disk, tape, flash memory, system memory, hard drive, and data signal embodied in a carrier wave.

21. A computer system for determining route redistribution at a device within a network, the system comprising:

memory; and

a processor configured for receiving an information packet from a neighbor source, the information packet identifying the neighbor source as a stub router and specifying route types that the neighbor source will advertise, wherein the stub router is identified as a router to which query generation is suppressed, and sending query packets requesting route information only to neighboring devices that have not been identified as stub routers upon receiving notice of a failed connection.

22. A computer system for reducing query generation for route redistribution within a network, the system comprising:

means for identifying a device as a stub router;

means for sending an information packet from the stub router to neighboring devices, the information packet identifying the neighbor source as a stub router and specifying route types that the stub router will advertise, wherein the stub router is identified as a router to which query generation is suppressed; and

upon receiving a query for route information other than the route types specified in the information packet, means for sending a response packet with routes identified as inaccessible.

30. The system of claim 22 wherein the stub router is configured for EIGRP.

31. The system of claim 22 wherein the network has a hub and spoke arrangement and the neighboring device is a hub router and the stub router is a spoke.

32. The system of claim 22 wherein the network includes a dual homed host.

33. The system of claim 22 wherein the route type that the stub router will advertise is connected routes.

34. The system of claim 22 wherein the stub router is in communication with a dual homed device.

35. The system of claim 22 wherein means for sending an information packet comprises transmitting a hello packet.

23. A computer program product for reducing query generation for route redistribution within a network, comprising:

code that utilizes information received at a router from a source which identifies the router as a stub router;

code that prepares an information packet to be sent from the stub router to neighboring devices, the information packet identifying the source as a stub router and specifying route types that the stub router will advertise; and

code that prepares a response packet to be sent with routes identified as inaccessible upon receiving a query for route information other than the route types specified in the information packet; and

a computer-readable storage medium for storing the codes.

24. A computer system for reducing query generation for route redistribution within a network, comprising:

a processor configured for receiving information at a router from a source identifying the router as a stub router, sending an information packet from the stub router to neighboring devices, the information packet identifying the source as a stub router and specifying route types that the stub router will advertise, and sending a response packet with routes identified as inaccessible upon receiving a query for route information other than the router types specified in the information packet; and

memory for storing information received by the processor.

25. A computer-implemented method for route redistribution within a network, the method comprising:

receiving information at a router identifying the router as a stub router; and

limiting an amount of route information sent by the stub router to a neighboring device in response to a query for route information, wherein limiting the amount of route information sent by the stub router comprises limiting the route information to include only connected routes.

26. A computer-implemented method for route redistribution within a network, the method comprising:

receiving information at a router identifying the router as a stub router; and

limiting an amount of route information sent by the stub router to a neighboring device in response to a query for route information, wherein limiting the amount of route information sent by the stub router comprises limiting the route information to include only summary routes.

27. A computer-implemented method for route redistribution within a network, the method comprising:

receiving information at a router identifying the router as a stub router; and

limiting an amount of route information sent by the stub router to a neighboring device in response to a query for route information, wherein limiting the amount of route information sent by the stub router comprises limiting the route information to include only static routes.

28. A computer-implemented method for route redistribution within a network, the method comprising:

receiving information at a router identifying the router as a stub router; and

limiting an amount of route information sent by the stub router to a neighboring device in response to a query for route information, wherein limiting the amount of route information sent by the stub router comprises limiting the route information to include only internal routes.

29. A computer-implemented method for route redistribution within a network, the method comprising:

receiving information at a router identifying the router as a stub router; and

limiting an amount of route information sent by the stub router to a neighboring device in response to a query for route information, wherein limiting the amount of route information sent by the stub router comprises limiting the route information to include only external routes.