Technique for fast activation of a secondary head-end node TE-LSP upon failure of a primary head-end node TE-LSP

• US 20070280102A1
• Filed: 06/02/2006
• Published: 12/06/2007
• Est. Priority Date: 06/02/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Vasseur, Jean-Philippe, Wainner, Warren Scott
• Granted Patent: US 8,208,372 B2
• Time in Patent Office: Days
• US Class Current: 370/225
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04L 12/5692 Selection among different networks
• CPC Class Codes: H04L 41/0663 Performing the actions predefined by failover planning, e.g. switching to standby network elements
• 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 45/302 Route determination based on requested QoS
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/728 for backup paths
• CPC Class Codes: H04L 47/746 Reaction triggered by a failure
• CPC Class Codes: H04L 47/822 Collecting or measuring resource availability data
• CPC Class Codes: H04L 47/825 Involving tunnels, e.g. MPLS

Abstract

A technique dynamically activates a secondary Traffic Engineering Label Switched Path (TE-LPs) at a secondary head-end node upon failure of a primary TE-LPs in a computer network. According to the novel technique, a primary head-end node establishes the primary TE-LPs having a primary bandwidth (BW) amount to a primary tail-end node. Also, the secondary head-end node establishes the secondary TE-LPS having zero BW to a secondary tail-end node (e.g., the same as the primary tail-end node). The secondary head-end node monitors the state of the primary TE-LPS, and in response to a failure (e.g., or other state change) substantially immediately adjusts the BW of the secondary TE-LPS to the primary BW amount (“activating” the TE-LPS). A “prior-hop” node to the primary and secondary head-end nodes originally forwarding traffic to the primary head-end node, may then begin forwarding traffic to the secondary head-end node, and thus onto the adjusted secondary TE-LPS.

Claims

1. A method for dynamically activating a secondary Traffic Engineering Label Switched Path (TE-LPS) at a secondary head-end node upon failure of a primary TE-LPS in a computer network, the method comprising:

establishing the primary TE-LPS having a primary bandwidth (BW) amount from a primary head-end node to a primary tail-end node;

establishing the secondary TE-LPS having zero BW from the secondary head-end node to a secondary tail-end node;

monitoring a state of the primary TE-LPS;

determining a failure of the primary TE-LPS; and

, in response,

substantially immediately adjusting the BW of the secondary TE-LPS to the primary BW amount.

2. The method as in claim 1, further comprising:

forwarding traffic to the primary head-end node from a prior-hop node of the primary and secondary head-end nodes; and

in response to failure of the primary TE-LPS, forwarding traffic from the prior-hop node to the secondary head-end node.

3. A computer readable medium containing executable program instructions for dynamically activating a secondary Traffic Engineering Label Switched Path (TE-LPS) at a secondary head-end node upon failure of a primary TE-LPS in a computer network, the primary TE-LPS having a primary bandwidth (BW) amount, the executable program instructions comprising program instructions adapted to:

establish a secondary TE-LPS having zero BW;

monitor a state of the primary TE-LPS;

determine a failure of the primary TE-LPS; and

, in response,

substantially immediately adjust the BW of the secondary TE-LPS to the primary BW amount.

4. An apparatus for dynamically activating a secondary Traffic Engineering Label Switched Path (TE-LPS) upon failure of a primary TE-LPS in a computer network, the primary TE-LPS having a primary bandwidth (BW) amount, the apparatus comprising:

means for establishing a secondary TE-LPS having zero BW;

means for monitoring a state of the primary TE-LPS;

means for determining a failure of the primary TE-LPS; and

, in response,

means for substantially immediately adjusting the BW of the secondary TE-LPS to the primary BW amount.

5. A system for dynamically activating a secondary Traffic Engineering Label Switched Path (TE-LPS) at a secondary head-end node upon failure of a primary TE-LPS in a computer network, the system comprising:

a primary head-end node configured to establish the primary TE-LPS, the primary TE-LPS having a primary bandwidth (BW) amount; and

a secondary head-end node configured to i) establish the secondary TE-LPS having zero BW, ii) monitor a state of the primary TE-LPS, iii) determine a failure of the primary TE-LPS, and, in response, iv) substantially immediately adjust the BW of the secondary TE-LPS to the primary BW amount.

6. The system as in claim 5, further comprising:

a prior-hop node of the primary and secondary head-end nodes, the prior-hop node configured to i) forward traffic to the primary head-end node, and ii) in response to failure of the primary TE-LPS, forward traffic to the secondary head-end node.

7. A secondary head-end node for dynamically activating a secondary Traffic Engineering Label Switched Path (TE-LPS) upon failure of a primary TE-LPS in a computer network, the primary TE-LPS having a primary bandwidth (BW) amount, the secondary head-end node comprising:

one or more network interfaces;

a processor coupled to the one or more network interfaces and adapted to execute software processes; and

a memory adapted to store a TE process executable by the processor, the TE process configured to;

i) establish the secondary TE-LPS having zero BW, ii) monitor a state of the primary TE-LPS, iii) determine a failure of the primary TE-LPS, and, in response, iv) substantially immediately adjust the BW of the secondary TE-LPS to the primary BW amount.

8. The secondary head-end node as in claim 7, wherein the one or more network interfaces are configured to receive traffic from a prior-hop node of the primary and secondary head-end nodes in response to failure of the primary TE-LPS.

9. The secondary head-end node as in claim 7, wherein the one or more network interfaces are configured to receive a notification from the primary head-end node to establish the secondary TE-LPS.

10. The secondary head-end node as in claim 9, wherein the received notification is one of either a flooded notification or a targeted notification to the secondary head-end node.

11. The secondary head-end node as in claim 9, wherein the received notification indicates one or more desired characteristics of the secondary TE-LPS to be established.

12. The secondary head-end node as in claim 11, wherein the one or more desired characteristics match one or more characteristics of the primary TE-LPS.

13. The secondary head-end node as in claim 12, wherein the one or more characteristics of the primary TE-LPS are indicated by a copy of a Path Request message used for the primary TE-LPS.

14. The secondary head-end node as in claim 7, wherein the TE process is configured to monitor the state of the primary TE-LPS by monitoring one or more requested triggers.

15. The secondary head-end node as in claim 14, wherein the one or more requested triggers are selected from a group comprising:

primary head-end node failure, primary TE-LPS intermediate node failure, explicit notifications, and primary head-end node state changes.

16. The secondary head-end node as in claim 15, wherein the explicit notifications are received from the primary head-end node.

17. The secondary head-end node as in claim 14, wherein the primary head-end node state changes are selected from a group comprising:

memory consumption and processor consumption.

18. The secondary head-end node as in claim 14, wherein the TE process is configured to determine a failure of the primary TE-LPS based on detecting one or more of the requested triggers.

19. The secondary head-end node as in claim 14, wherein the one or more network interfaces are configured to receive a notification from the primary head-end node indicating the one or more requested triggers.

20. The secondary head-end node as in claim 14, wherein the one or more requested triggers comprise one or more combined triggers.

21. The secondary head-end node as in claim 7, wherein the one or more network interfaces are configured to receive notifications from the primary head-end node embodied as a message selected from a group comprising:

Interior Gateway Protocol (IGP) messages, Bidirectional Forwarding Detection (BFD) messages, and Path Computation Element Protocol (PCEP) messages.

22. The secondary head-end node as in claim 7, wherein the TE process is configured manually to establish the secondary TE-LPS and to monitor the state of the primary TE-LPS.

23. The secondary head-end node as in claim 7, wherein the TE process is further configured to determine that the secondary head-end node is unable to establish the secondary TE-LPS, and in response, inform the primary head-end node of the inability.

24. The secondary head-end node as in claim 7, wherein the TE process is further configured to monitor a state of the established secondary TE-LPS, and to inform the primary head-end node of any configurable changes to the state of the secondary TE-LPS.

25. The secondary head-end node as in claim 7, wherein the TE process is further configured to determine a maximum available BW for the secondary TE-LPS, wherein the TE process is configured to adjust the BW of the secondary TE-LPS to a lesser BW of the maximum available BW and the primary BW.

26. The secondary head-end node as in claim 25, wherein the TE process is further configured to inform the primary head-end node that the maximum available BW is less than the primary BW.

27. The secondary head-end node as in claim 7, wherein the TE process is further configured to determine a maximum available BW for the secondary TE-LPS, wherein the TE process is configured to determine that the secondary TE-LPS cannot be established in the event the maximum available BW for the secondary TE-LPS is less than the primary BW.

28. The secondary head-end node as in claim 27, wherein the TE process is further configured to inform the primary head-end node of at least one of either the maximum available BW being less than the primary BW or that the secondary TE-LPS cannot be established.

29. The secondary head-end node as in claim 27, wherein the TE process is configured to determine that the secondary TE-LPS cannot be established prior to determination of a failure of the primary TE-LPS.

30. The secondary head-end node as in claim 7, wherein the TE process is further configured to determine whether the primary head-end node is able to redirect the primary TE-LPS after a failure, and if so, ceasing the adjustment of BW of the secondary TE-LPS.

31. A primary head-end node for use with dynamically activating a secondary Traffic Engineering Label Switched Path (TE-LPS) at a secondary head-end node upon failure of a primary TE-LPS in a computer network, the primary head-end node comprising:

one or more network interfaces configured to receive traffic from a prior-hop node of the primary and secondary head-end nodes;

a processor coupled to the one or more network interfaces and adapted to execute software processes; and

a memory adapted to store a TE process executable by the processor, the TE process configured to;

i) establish the primary TE-LPS having a primary BW, ii) determine a failure of the primary TE-LPS, iii) determine that the received traffic has been redirected by the prior-hop node to the secondary head-end node, iv) determine that the secondary TE-LPS has been adjusted to the primary BW, and v) in response to determining the failure, the redirection, and the adjustment, tearing down the primary TE-LPS.

32. The primary head-end node as in claim 31, wherein the one or more network interfaces are configured to send a notification to the secondary head-end node to request establishment the secondary TE-LPS.

33. The primary head-end node as in claim 32, wherein the notification indicates one or more desired characteristics of the secondary TE-LPS and one or more requested triggers for which the secondary head-end node is requested to monitor to determine a failure of the primary TE-LPS.

34. The primary head-end node as in claim 31, wherein the TE process is further configured to inform the prior-hop node of the primary TE-LPS failure.

35. The primary head-end node as in claim 34, wherein the TE process is configured to inform the prior-hop node of the primary TE-LPS failure by one of either an explicit notification message or by shutting down a link between the prior-hop node and the primary head-end node.