PATH REROUTE IN A COMPUTER NETWORK

• US 20090225650A1
• Filed: 03/07/2008
• Published: 09/10/2009
• Est. Priority Date: 03/07/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Vasseur, Jean-Philippe Marcel
• Granted Patent: US 7,839,767 B2
• Time in Patent Office: Days
• US Class Current: 370/218
• CPC Class Codes: H04L 41/0668 by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/507 Label distribution

Abstract

In an example embodiment, a method is provided that receives a first label from an area border routing device. Here, the first label is associated with a first routing device, which is an immediate downstream neighbor of the area border routing device. The first label is then associated with a second label that is associated with a second routing device. In an example, the first label is received from the area border routing device along a path. Data that includes the second label subsequently is received and the second label in the data is replaced with the first label upon a failure of the area border router. The data then is encapsulated in an alternate path to the first routing device.

Claims

1. A method comprising:

transmitting an advertisement that includes a destination address to be protected by an area border routing device;

receiving a response to the advertisement, the response including a plurality of address blocks associated with a plurality of paths, the plurality of paths being used by the area border routing device to route to the destination address; and

establishing a path to the area border routing device for each of the plurality of address blocks.

2. The method of claim 1, wherein the establishing of the path comprises establishing a plurality of additional paths to the area border routing device, each additional path of the plurality of additional paths corresponding to one address block of the plurality of address blocks.

3. The method of claim 1, wherein the establishing of the path comprises assigning an existing path destined to the area border routing device.

4. The method of claim 1, wherein the establishing of the path comprises establishing a new path to the area border routing device.

5. The method of claim 1, wherein the response further includes a label associated with a routing device, the routing device being an immediate downstream neighbor of the area border routing device.

6. The method of claim 1, further comprising transmitting an additional advertisement that includes an association of the path with each of the plurality of address blocks.

7. The method of claim 1, further comprising associating the path with the destination address to be protected by the area border router.

8. The method of claim 1, wherein the response is transmitted by the area border routing device.

9. The method of claim 1, wherein each address block of the plurality of address blocks is associated with one path of the plurality of paths.

10. A method comprising:

receiving an advertisement that includes a destination address to be protected;

identifying a path associated with the destination address, the path being associated with an address block; and

transmitting a response to the advertisement, the response including the address block.

11. The method of claim 10, wherein the path is a label switched path.

12. The method of claim 10, wherein the path is destined to the destination address.

13. A method comprising:

receiving an advertisement that includes an association of an upstream path with an address block;

matching the upstream path to a downstream path based on the address block;

accessing a label associated with a first neighboring routing device in the downstream path, the first neighboring routing device being an immediate downstream neighbor; and

transmitting the label to a second neighboring routing device in the upstream path, the second neighboring routing device being an immediate upstream neighbor.

14. The method of claim 13, where the label is transmitted to the second routing device by way of the upstream path.

15. The method of claim 13, further comprising transmitting a request to bind the upstream path with the downstream path, the request being transmitted to the first neighboring routing device.

16. The method of claim 13, wherein the request is a Resource Reservation Protocol path message.

17. The method of claim 15, wherein the request is transmitted to the first neighboring routing device before a failure of an area border routing device.

18. A method comprising:

receiving a first label from an area border routing device, the first label being associated with a first routing device, the first routing device being an immediate downstream neighbor of the area border routing device; and

associating the first label with a second label, the second label being associated with a second routing device.

19. The method of claim 18, wherein the first label is received from the area border routing device along a path, the method further comprising:

receiving data that includes the second label;

replacing the second label in the data with the first label upon a failure of the area border router; and

encapsulating the data in an alternate path to the first routing device.

20. The method of claim 19, further comprising detecting the failure of the area border router.

21. The method of claim 19, wherein the encapsulating of the data comprises attaching a third label associated with the alternate path to the data.

22. An apparatus comprising:

at least one processor; and

a machine-readable medium in communication with the at least one processor, the machine-readable medium being configured to store a path computation and Multiprotocol Label Switching (MPLS) reroute module, the path computation and MPLS reroute module being executed by the at least one processor cause the operations to be performed, comprising;

receiving a first label from an area border routing device along a path, the first label being associated with a first routing device, the first routing device being an immediate downstream neighbor of the area border routing device;

associating the first label with a second label, the second label being associated with the apparatus;

receiving data that includes the second label;

detecting a failure of the area border router;

replacing the second label in the data with the first label upon a failure of the area border router; and

encapsulating the data in an alternate path to the first routing device.