Automatic protection switching using link-level redundancy supporting multi-protocol label switching

1. A backup controller that provides protection switching in the event of a link failure of a routing node that delivers data packets to a computer network via a plurality of links, the backup controller comprising:

a backup path manager that, for at least one link of the routing node, identifies a backup routing path for forwarding affected data packets in the event of a failure of the at least one link, wherein the backup routing path is determined prior to a failure of the at least one link;

a link monitor that monitors the plurality of links to determine when a link fails;

a backup packet processor that, when a link which has a backup routing path fails, attaches backup routing path instructions to affected data packets routed over the failed link, and

forwards the affected data packets via the backup routing path; and

a loop prevention mechanism for determining that the network has converged and is loop-free.

2. A backup controller according to claim 1 , wherein the backup controller further advertises a link failure to the network using a routing protocol.

3. A backup controller according to claim 1 , wherein the backup routing path instructions include a label stack based on Multi-Protocol Label Switching (MPLS).

4. A backup controller according to claim 3 , wherein the label stack includes labels for a packet source and a packet destination.

5. A backup controller according to claim 1 , wherein the backup routing path is a Label Switched Path (LSP).

6. A backup controller according to claim 5 , wherein the LSP is based on network topology information.

7. A backup controller according to claim 6 , wherein the network topology information is derived from a network protocol.

8. A backup controller according to claim 1 , wherein the computer network uses a label switching routing protocol.

9. A method of providing protection switching in the event of a link failure of a computer network routing node that delivers data packets to a computer network routing node that delivers data packets to a computer network via a plurality of links, the method comprising:

identifying, for at least one link of the routing node, a backup routing path for forwarding affected data packets in the event of a failure of the at least one link, wherein the backup routing path is identified prior to the failure of the at least one link;

monitoring the plurality of links to determine when a link fails;

when a link which has a backup routing path fails, attaching backup routing path instructions to affected data packets routed over the failed link;

forwarding the affected data packets via the backup routing path; and

determining that the network has converged and is loop-free using a loop prevention algorithm.

10. A method according to claim 9 , further comprising advertising a link failure to the network using a routing protocol.

11. A method according to claim 9 , further comprising establishing a new network route to replace a failed link.

12. A method according to claim 9 , wherein the step of determining that the network has converged and is loop free uses a loop prevention algorithm.

13. A method according to claim 9 , wherein the backup routing path instructions include a label stack based on Multi-Protocol Label Switching (MPLS).

14. A method according to claim 13 , wherein the label stack includes labels for a packet source and a packet destination.

15. A method according to claim 9 , wherein the backup routing path is a Label Switched Path (LSP).

16. A method according to claim 15 , wherein the LSP is based on network topology information.

17. A method according to claim 16 , wherein the network topology information is derived from a network protocol.

18. A method according to claim 9 , wherein the computer network uses a label switching routing protocol.

19. A data router that delivers data packets to a computer network via a plurality of links, the router providing protection switching in the event of a link failure, the router comprising:

a data interference for data packets to enter and exit the router; and

a backup controller including:

a backup path manager that, for at least one link of the routing node,

identifies a backup routing path for forwarding affected data packets in the event of a failure of the at least one link, wherein the backup routing path is identified prior to the failure of the at least one link;

a link monitor that monitors the plurality of links to determine when a link fails;

a backup packet processor that, when a link which has a backup routing path fails, attaches backup routing path instructions to affected data packets routed over the failed link, and forwards the affected data packets via the backup routing path; and

a failed link recalculator that establishes a new network route to replace a failed link and determines that the network has converged and is loop free using a loop prevention algorithm.

20. A data router according to claim 19 , wherein the router further advertises a link failure to the network using a routing protocol.

21. A data router according to claim 19 , wherein the failed link recalculator uses a loop prevention algorithm after a link failure to determine that the network has converged and is loop-free.

22. A data router according to claim 19 , wherein the backup routing path instructions include a label stack based on Multi-Protocol Label Switching (MPLS).

23. A data router according to claim 22 wherein the label stack includes labels for a packet source and a packet destination.

24. A data router according to claim 19 , wherein the backup routing path is a next node on a Label Switched Path (LSP).

25. A data router according to claim 24 , wherein the LSP is based on network topology information.

26. A data router according to claim 25 , wherein the network topology information is derived from a network protocol.

27. A data router according to claim 19 , wherein the computer network uses a label switching routing protocol.

28. computer network having a plurality of data packet streams, the network comprising:

a plurality of subnetworks, each subnetwork having at least one application that generates a stream of data packets for transmission over the computer network; and

a plurality of routers that deliver data packets to the network via a plurality of links, at least one router providing protection switching in the event of a link failure, the at least one router including:

a plurality of data interfaces for streams of data packets to enter and exit the at least one router; and

a backup controller having:

a backup path manager that, for at least one link of the routing node, identifies a backup routing path for forwarding affected data packets in the event of a failure of the at least one link, wherein the backup routing path is identified prior to the failure of the at least one link;

a link monitor that monitors the plurality of links to determine when a link fails; and

a backup packet processor that, when a link which has a backup routing path fails, attaches backup routing path instructions to affected data packets routed over the failed link, and forwards the affected data packets via the backup routing path; and

a failed link recalculator that establishes a new network route to replace a failed link and determines that the network has converged and is loop-free using a loop prevention algorithm.

29. Computer network according to claim 28 , wherein the at least one router further advertises a link failure to the network using a routing protocol.

30. Computer network according to claim 28 , wherein the failed link recalculator uses a loop prevention algorithm after a link failure to determine that the network has converged and is loop-free.

31. A computer network according to claim 28 , wherein the backup routing path instructions include a label stack based on Multi-Protocol Label Switching (MPLS).

32. A computer network according to claim 31 , wherein the label stack includes labels for a packet source and a packet destination.

33. A computer network according to claim 28 , wherein the backup routing path is a Label Switched Path (LSP).

34. A computer network according to claim 33 , wherein the LSP is based on network topology information.

35. A computer network according to claim 34 , wherein the network topology information is derived from a network protocol.

36. A computer network according to claim 28 , wherein the computer network uses a label switching routing protocol.

37. A computer program product for use on a computer system for providing protection switching in the event of a link failure of a computer network routing node that delivers data packets to a computer network via a plurality of links, the computer program product comprising a computer-usable medium having computer-readable program code thereon, the computer readable program code including:

program code for identifying, for at least one link of the routing node, a backup routing path for forwarding affected data packets, the backup routing path to be used in the event of a failure of the at least one link, wherein the backup routing path is identified prior to the failure of the at least one link;

backup routing path for forwarding affected data packets in the event of a failure of the at least one link;

program code for, when a link which has a backup routing path fails, attaching backup routing path instructions to affected data packets routed over the failed link;

program code for forwarding the affected data packets via the backup routing path; and

program code for using a loop prevention algorithm after a link failure to determine that the network has converged and is loop-free.

38. A computer program product according to claim 37 , further comprising program code for advertising a link failure to the network using a routing protocol.

39. A computer program product according to claim 37 , further comprising program code for establishing a new network route to replace a failed link.

40. A computer program product according to claim 37 , wherein the backup routing path includes a label stack based on Multi-Protocol Label Switching (MPLS).

41. A computer program product according to claim 40 , wherein the label stack includes a packet source and a packet destination.

42. A computer program product according to claim 37 , wherein the backup routing path is a Label Switched Path (LSP).

43. A computer program product according to claim 42 , wherein the LSP is based upon network topology information.

44. A computer program product according to claim 43 , wherein the network topology information is derived from a network protocol.

45. A computer program product according to claim 37 , wherein the computer network uses a label switching routing protocol.

46. A backup controller that provides protection switching in the event of a link failure of a routing node that delivers data packets to a computer network via a plurality of links, the backup controller comprising:

means for identifying, for at least one link of the routing node, a backup routing path for forwarding affected data packets in the event of a failure of the at least one link; wherein the backup routing path is identified prior to the failure of the at least one link

means for monitoring the plurality of links to determine when a link fails;

means for attaching, when a link which has a backup routing path fails,

backup routing path instructions to affected data packets routed over the failed link; means for forwarding the affected data packets via the backup routing path; and

means for using a loop prevention algorithm after a link failure to determine that the network has converged and is loop-free.

47. A backup controller according to claim 46 , further comprising means for advertising a link failure to the network using a routing protocol.

48. A backup controller according to claim 46 , further comprising means for establishing a new network route to replace a failed link.

49. A backup controller according to claim 46 , when the backup routing path instructions include a label stack based on Multi-Protocol Label Switching (MPLS).

50. A backup controller according to claim 49 , wherein the label stack includes labels for a packet source and a packet destination.

51. A backup controller according to claim 46 , wherein the backup routing path is a Label Switched Path (LSP).

52. A backup controller according to claim 51 , wherein the LSP is based upon network topology information.

53. A backup controller according to claim 52 , wherein the network topology information is derived from a network protocol.

54. A backup controller according to claim 46 , wherein the computer network uses a label switching routing protocol.