System and method for reconfiguring a telecommunications network to its normal state after repair of fault

• US 6,222,821 B1
• Filed: 06/22/1995
• Issued: 04/24/2001
• Est. Priority Date: 06/22/1995
• Status: Expired due to Term

• Current Assignee: Verizon Patent and Licensing Incorporated (Verizon Communications Inc.)
• Original Assignee: MCI Communications Corporation (Verizon Communications Inc.)
• Inventors: Russ, Will, Sees, Mark Wayne, Wagner, Clinton Allen, Bengston, Lee Dennis
• Primary Examiner(s): Kizou, Hassan
• Application Number:
  US08/493,741
• Time in Patent Office: 2,133 Days
• Field of Search: 370/16, 370/16.1, 370/58.1, 370/58.2, 370/60, 370/60.1, 370/216, 370/217, 370/221, 370/225, 370/226, 370/227-228
• US Class Current: 370/227
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04Q 3/0079 involving restoration of networks, e.g. disaster recovery, self-healing networks

Abstract

To revert the topology of a network to its original or normal state after an alternate route has been found for bypassing traffic away from a malfunctioned link that has since been repaired, an Operation Support System (OSS) sends to each of the custodial sender/chooser nodes and the tandem nodes that form the alternate route respective commands to revert the operation(s) that each node had performed during distributed restoration. The OSS is able to identify the custodial nodes by the fact that those nodes perform more operations than the tandem nodes. The operations that were performed during the distributed restoration process were recorded and the thus restored topology of the network is mapped and stored. Upon receipt from the different nodes that the malfunctioned link has been repaired, the OSS sends to each of the nodes a specific command to perform the inverse of the operation(s) that that node had performed during the restoration. The custodial nodes are ordered to perform their inverse operations first so that the malfunctioned link that has since been repaired once again connects the custodial nodes. A path verification process is next performed to ensure the integrity of the newly repaired path. Once the integrity of the repaired path is confirmed, each of the tandem nodes performs the inverse of the operation it had performed during the distributed restoration to disconnect the cross connected ports within each of the tandem nodes.

Claims

1. In a telecommunications network having a plurality of nodes interconnected by a plurality of working and spare links, after functionality of at least one failed working link is restored by a distributed restoration scheme, a method of automatically reconfiguring said network to the topology it had before said one working link failed, comprising the steps of:

(a) identifying each of the nodes having performed two cross-connect operations for rerouting traffic traveling on a route including said one failed working link to an alternate route as custodial nodes bracketing said one failed working link;

(b) identifying at least one node to which respective connections via corresponding spare links were made by said custodial nodes to establish said alternate route when said one working link failed as a tandem node;

(c) identifying in each of said custodial nodes the port to which one end of said failed working link is connected, the port to which one of said respective spare links to said tandem node is coupled, and the port through which traffic on said route is routed to other nodes of said network; and

(d) disconnecting said traffic routed through port from said spare link coupled port and cross-connecting said traffic routed through port to said failed working link connected port in each of said custodial nodes.

2. Method of claim 1, wherein said two cross-connect operations further comprises the steps of:

disconnecting said failed working link connected port to said traffic routed through port; and

cross-connecting said traffic routed through port to said spare link coupled port.

3. Method of claim 1, further comprising the steps of:

verifying said functionality having been restored to said one failed working link; and

using said restored one failed working link to reestablished said route.

4. Method of claim 1, further comprising the step of:

disconnecting any cross-connection made in said tandem node for establishing said alternate route when said one working link failed.

5. Method of claim 3, further comprising the step of:

disconnecting any cross-connection made in said tandem node for establishing said alternate route when said one working link failed.

6. Method of claim 1, before any of steps (a) to (d), further comprising the steps of:

monitoring respective statuses from each of said custodial and tandem nodes; and

detecting from each of said custodial nodes an indication that said functionality has been restored in said failed working link.

7. Method of claim 1, further comprising the steps of:

storing in a memory data representative of said network including the identity of each of said nodes, the cross-connect operations performed by each of said nodes, the respective connections of working and spare links to the respective ports in each of said nodes, and the identity of the respective ports in each of said nodes.

8. In a telecommunications network having a plurality of nodes interconnected by a plurality of working and spare links, after functionality of at least one failed working link is restored by a distributed restoration scheme, a method of automatically reconfiguring said network to the topology it had before said one working link failed, comprising the steps of:

(a) identifying each of the nodes having performed two cross-connect operations for rerouting traffic traveling on a route including said one failed working link to an alternate route as custodial nodes bracketing said one failed working link;

(b) identifying the plurality of nodes along said alternate route as tandem nodes, each of said tandem nodes having respective spare link ports for interconnecting with each other and communicatively coupling to said custodial nodes;

(c) identifying in each of said custodial nodes a one port to which one end of said failed working link is connected, an other port to which the tandem node adjacent said each custodial node is communicatively coupled, and an another port through which traffic on said route is routed to any other node of said network; and

(d) disconnecting said another port from said other port and cross-connecting said another port to said one port in each of said custodial nodes.

9. Method of claim 8, wherein said two cross-connect operations further comprises the steps of:

disconnecting said one port from said another port; and

cross-connecting said another port to said other port.

10. Method of claim 8, further comprising the steps of:

verifying said functionality having been restored to said one failed working link; and

using said restored one failed working link to reestablished said route.

11. Method of claim 8, further comprising the step of:

disconnecting any cross-connection made in any of said tandem nodes for establishing said alternate route when said one working link failed.

12. Method of claim 8, before any of steps (a) to (d), further comprising the steps of:

monitoring respective statuses from each of said custodial and tandem nodes; and

detecting from each of said custodial nodes an indication that said functionality has been restored in said failed working link.

13. Method of claim 8, further comprising the steps of:

storing in a memory data representative of said network including the identity of each of said nodes, the cross-connect operations performed by each of said nodes, the respective connections of working and spare links to the respective ports in each of said nodes, and the identity of the respective ports in each of said nodes.

14. In a telecommunications network having a plurality of nodes interconnected by a plurality of working and spare links, after functionality of at least one failed working link is restored by a distributed restoration scheme, a method of automatically reverting said network to the topology it had before said one working link failed, comprising the steps of:

(a) identifying each of the nodes having performed two cross-connect operations for rerouting traffic traveling on a route including said one failed working link to an alternate route as custodial nodes bracketing said one failed working link;

(b) identifying as tandem nodes each of the nodes having performed one cross-connect operation for functioning as part of said alternate route to accept rerouted traffic, said tandem nodes interconnected with each other, the tandem node at the respective ends of said alternate route being coupled to the one of said custodial nodes adjacent thereto;

(c) identifying in each of said custodial nodes a one port to which one end of said failed working link is connected, an other port to which said tandem node adjacent said each custodial node is coupled, and an another port through which traffic on said route is routed to any other node of said network; and

(d) disconnecting said another port from said other port and cross-connecting said another port to said one port in each of said custodial nodes.

15. Method of claim 14, wherein said two cross-connect operations performed by each of said custodial nodes further comprises the steps of:

disconnecting said one port from said another port; and

cross-connecting said another port to said other port.

16. Method of claim 14, wherein said one cross-connect operation performed by each of said tandem nodes comprises the step of:

cross-connecting a port coupled to an incoming spare link to a port coupled to an outgoing spare link in said each tandem node.

17. Method of claim 14, further comprising the steps of:

verifying said functionality having been restored to said one failed working link; and

using said restored one failed working link to reestablished said route.

18. Method of claim 14, further comprising the step of:

disconnecting said one cross-connection operation made in any of said tandem nodes for establishing said alternate route when said one working link failed.

19. Method of claim 14, before any of steps (a) to (d), further comprising the steps of:

monitoring respective statuses from each of said custodial and tandem nodes; and

detecting from each of said custodial nodes an indication that said functionality has been restored in said failed working link.

20. Method of claim 14, further comprising the steps of:

storing in a memory data representative of said network including the identity of each of said nodes, any cross-connect operation performed by each of said nodes, the respective connections of working and spare links to the respective ports in each of said nodes, and the identity of the respective ports in each of said nodes.

21. In a telecommunications network having a plurality of nodes interconnected by a plurality of working and spare links, after functionality of at least one failed working link is restored by a distributed restoration scheme, a method of automatically reverting said network to the topology it had before said one working link failed, comprising the steps of:

(a) identifying each of the nodes having performed two cross-connect operations for rerouting traffic traveling on a route including said one failed working link to an alternate route as custodial nodes bracketing said one failed working link;

(b) identifying at least one node having performed one cross-connect operation for functioning as part of said alternate route a tandem node, said tandem node having respective end ports each coupled to a spare link connecting one of said custodial nodes;

(c) identifying in each of said custodial nodes a one port to which one end of said failed working link is connected, an other port to which said spare link coupled to said tandem node is connected, and an another port through which traffic on said route is routed to any other node of said network; and

(d) disconnecting said another port from said other port and cross-connecting said another port to said one port in each of said custodial nodes.

22. Method of claim 21, wherein said two cross-connect operations performed by each of said custodial nodes further comprises the steps of:

disconnecting said one port from said another port; and

cross-connecting said another port to said other port.

23. Method of claim 22, wherein said one cross-connect operation performed by said tandem node comprises the step of:

cross-connecting a port coupled to an incoming spare link to a port coupled to an outgoing spare link in said tandem node.

24. Method of claim 22, further comprising the steps of:

verifying said functionality having been restored to said one failed working link; and

using said restored one failed working link to reestablished said route.

25. Method of claim 22, further comprising the step of:

disconnecting said one cross-connection operation made in said tandem node for establishing said alternate route when said one working link failed.

26. Method of claim 22, before any of steps (a) to (d), further comprising the steps of:

monitoring respective statuses from each of said custodial and tandem nodes; and

detecting from each of said custodial nodes an indication that said functionality has been restored in said failed working link.

27. Method of claim 22, further comprising the steps of:

storing in a memory data representative of said network including the identity of each of said nodes, any cross-connect operation performed by each of said nodes, the respective connections of working and spare links to the respective ports in each of said nodes, and the identity of the respective ports in each of said nodes.

28. In a telecommunications network having a plurality of node switch means interconnected by a plurality of working and spare links, after functionality of at least one failed working link is restored by a distributed restoration scheme, a system for automatically reverting said network to the topology it had before said one working link failed, comprising:

two custodial node switch means bracketing said one failed working link each having performed two cross-connect operations for rerouting traffic traveling on a route including said one failed working link to an alternate route;

a plurality of tandem node switch means each having performed one cross-connect operation for functioning as part of said alternate route to accept rerouted traffic, said tandem node switch means interconnected with each other, the tandem node switch means at the respective ends of said alternate route being coupled to the one of said custodial node switch means adjacent thereto;

each of said custodial node switch means including a one port to which one end of said failed working link is connected, an other port to which said tandem node switch means adjacent said each custodial node switch means is coupled, and an another port through which traffic on said route is routed to any other node of said network;

each of said custodial node switch means disconnecting said another port from said other port and cross-connecting said another port to said one port for reverting said network to said topology.

29. System of claim 28, wherein each of said custodial node switch means performs said two cross-connect operations by disconnecting said one port from said another port and cross-connecting said another port to said other port.

30. System of claim 28, wherein each of said tandem node switch means performs said one cross-connect operation by cross-connecting a port coupled to an incoming spare link to a port coupled to an outgoing spare link in said each tandem node switch means.

31. System of claim 28, further comprising:

control means for verifying said functionality has been restored to said one failed working link and using said restored one failed working link to reestablished said route.

32. System of claim 28, further comprising:

control means for disconnecting said one cross-connection operation made in any of said tandem node switch means for establishing said alternate route when said one working link failed.

33. System of claim 28, further comprising:

control means for monitoring respective statuses from each of said custodial and tandem node switch means and detecting from each of said custodial node switch means an indication that said functionality has been restored in said failed working link.

34. System of claim 28, further comprising:

memory means for storing data representative of said network including the identity of each of said node switch means, any cross-connect operation performed by each of said node switch means, the respective connections of working and spare links to the respective ports in each of said node switch means, and the identity of the respective ports in each of said node switch means, said custodial node switch means performing said disconnecting and cross-connecting operations in response to data stored in said memory means.

35. In a telecommunications network having a plurality of nodes interconnected by a plurality of working and spare links, after functionality of at least one failed working link is restored by a distributed restoration scheme, a system for automatically reconfiguring said network to the topology it had before said one working link failed, comprising:

means for identifying each of the nodes having performed two cross-connect operations for rerouting traffic traveling on a route including said one failed working link to an alternate route as custodial nodes bracketing said one failed working link;

means for identifying at least one node having performed one cross-connect operation for functioning as part of said alternate route a tandem node, said tandem node having respective end ports each coupled to a spare link connecting one of said custodial nodes;

means for identifying in each of said custodial nodes a one port to which one end of said failed working link is connected, an other port to which said spare link coupled to said tandem node is connected, and an another port through which traffic on said route is routed to any other node of said network; and

switch means for disconnecting said another port from said other port and cross-connecting said another port to said one port in each of said custodial nodes.

36. System of claim 35, wherein each of said custodial nodes performs said two cross-connect operations by disconnecting said one port from said another port and cross-connecting said another port to said other port.

37. System of claim 35, wherein said tandem node performs said one cross-connect operation by cross-connecting therein a port coupled to an incoming spare link to a port coupled to an outgoing spare link.

38. System of claim 35, further comprising:

means for verifying said functionality having been restored to said one failed working link; and

means for using said restored one failed working link to reestablished said route.

39. System of claim 35, wherein said switch means further disconnects said one cross-connection operation made in said tandem node for establishing said alternate route when said one working link failed.

40. System of claim 35, further comprising:

means for monitoring respective statuses from each of said custodial and tandem nodes; and

means for detecting from each of said custodial nodes an indication that said functionality has been restored in said failed working link.

41. System of claim 35, wherein each of said nodes is an electronic cross-connect switch.

42. System of claim 35, further comprising:

memory means for storing data representative of said network including the identity of each of said nodes, any cross-connect operation performed by each of said nodes, the respective connections of working and spare links to the respective ports in each of said nodes, and the identity of the respective ports in each of said nodes, said custodial nodes switch means performing said disconnecting and cross-connecting operations in response to data stored in said memory means.