Network switch failure restoration

• US 6,331,905 B1
• Filed: 04/01/1999
• Issued: 12/18/2001
• Est. Priority Date: 04/01/1999
• Status: Expired due to Term

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Ellinas, Georgios, Stern, Thomas E.
• Primary Examiner(s): Pascal, Leslie
• Assistant Examiner(s): Bello, Agustin
• Application Number:
  US09/282,609
• Time in Patent Office: 992 Days
• Field of Search: 359/110, 359/117, 359/119, 370/219, 370/220
• US Class Current: 398/2
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• CPC Class Codes: H04J 14/0241 Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
• CPC Class Codes: H04J 14/0284 WDM mesh architectures
• CPC Class Codes: H04J 14/0291 Shared protection at the optical multiplex section (1:1, n:m)
• CPC Class Codes: H04Q 11/0062 Network aspects
• CPC Class Codes: H04Q 2011/0081 Fault tolerance; Redundancy; Recovery; Reconfigurability
• CPC Class Codes: H04Q 2011/009 Topology aspects
• CPC Class Codes: H04Q 2011/0092 Ring

Abstract

A system and method for automatically restoring a network which contains a node with a failed switch. Protection cycles are generated for the network to be restored and cyclegroups are generated from the protection cycles. Each node is provided with protection switches which internally interconnect the input/output ports to connecting links via interconnecting protection fibers. The selection of which internal protection fibers upon which to switch transmitted information onto allows the node to be configured to create merged cyclegroups. Thus if a failure in the central switch is detected, the transmitted information is diverted to a selected protection fiber corresponding to a merged cyclegroup so that the information can be automatically passed around the failed switch via the protection fibers. Each protection switch has associated mapping data which defines which protection fiber will be switched to based upon the input and output link for the transmission that is required to be sent through the node. The system and method applies to non-planar networks as well as planar networks.

Claims

1. A method for restoring a network comprising a plurality of nodes connected by links, wherein each of said nodes comprises a central switch connected to at least one working fiber, comprising the steps of:

providing at least one protection switch for making connections to respective ones of a plurality of protection fibers for at least one of said nodes, wherein said protection switch is capable of switching information from a working fiber to a respective one of said plurality of protection fibers;

providing mapping data indicative of which of said plurality of protection fibers should be switched to by said at least one protection switch in response to a failure of said central switch, wherein said mapping data is calculated responsive to identified cyclegroups for said network; and

if a failure of said central switch occurs, causing said at least one protection switch to switch said information from said working fiber to said protection fiber identified by said mapping data.

2. The method of claim 1, wherein said at least one of said nodes is connected to a plurality of said links including an input link and an output link, and said mapping data is organized responsive to the input link and said output link for transmission of said information.

3. The method of claim 2, wherein said mapping data identifies a connection for each of said at least one protection switch based on said input link and output link'"'"'s identity.

4. The method of claim 1, wherein said mapping data is generated prior to said operation of said network.

5. The method of claim 1, wherein said switching of said information to said identified protection fiber restores operation of said at least one of said nodes.

6. The method of claim 1, wherein said mapping data is stored as a table.

7. The method of claim 1, wherein said cyclegroups comprise at least one protection cycle identified for said network.

8. The method of claim 1, wherein said network is non-planar.

9. The method of claim 1, wherein said network is planar.

10. A system for restoring a network comprising:

a plurality of nodes connected by links, wherein each of said plurality of nodes comprises a central switch connected to at least one working fiber for transferring information between said links;

at least one protection switch for making connections to a plurality of protection fibers for at least one of said plurality of nodes wherein said protection switch is capable of switching information from a working fiber to one of said plurality of protection fibers;

a memory in said at least one node for storing mapping data indicative of which of said plurality of protection fibers should be switched to in response to a failure of said central switch, wherein said mapping data'"'"'s entry is calculated responsive to identified cyclegroups for said network; and

a fault detector which detects if a fault occurs in said central switch of said at least one node.

11. The system of claim 10, wherein said at least one node is connected to a plurality of said links including an input link and an output link, and said mapping data is organized responsive to the input link and said output link for transmission of said information.

12. The system of claim 11, wherein said mapping data identifies a connection for each one of said at least one protection switch based on said input link'"'"'s and said output link'"'"'s identity.

13. The method of claim 10, wherein said mapping data is generated prior to said operation of said network.

14. The system of claim 10, wherein said switching of said information to said protection fiber indicated by said mapping data restores operation of said at least one of said plurality of nodes.

15. The system of claim 10, wherein said mapping data is stored as a table.

16. The system of claim 10, wherein said cyclegroups comprise at least one protection cycle identified for said network.

17. The system of claim 10, wherein said network is non-planar.

18. The system of claim 10, wherein said network is planar.

19. An apparatus for restoring a network, wherein said network comprises a plurality of nodes connected by links and wherein each of said plurality of nodes comprises a central switch connected to at least one working fiber for transferring information between said links, comprising:

at least one protection switch for making connections to a plurality of protection fibers, wherein said at least one protection switch is capable of switching information from a working fiber to one of said plurality of protection fibers in at least one of said plurality of nodes;

a memory coupled to said at least one of said plurality of nodes which stores mapping data indicative of which of said plurality of protection fibers should be switched to in response to a failure of said central switch in a respective one of said at least one of said plurality of nodes, wherein said mapping data'"'"'s entry is calculated responsive to identified cyclegroups for said network; and

a fault detector which detects if a fault occurs in said central switch of each of said plurality of nodes.

20. The apparatus of claim 19, wherein each of said at least one of said plurality of nodes is connected to a plurality of said links, including an input link and an output link, and said mapping data is organized to be responsive to the input link and said output link for transmission of said information.

21. The apparatus of claim 20, wherein said mapping data identifies a connection for each said protection switch based on said input link and output link'"'"'s identity.

22. The method of claim 19, wherein said mapping data is generated prior to said operation of said network.

23. The apparatus of claim 19, wherein said switching of said information to said protection fiber indicated by the mapping data restores operation of a respective one of said at least one of said plurality of nodes.

24. The apparatus of claim 19, wherein said mapping data is stored as a table.

25. The apparatus of claim 19, wherein said cyclegroups comprise at least one protection cycle identified for said network.

26. The apparatus of claim 19, wherein said network is non-planar.

27. The apparatus of claim 19, wherein said network is planar.

28. The apparatus of claim 19, wherein said mapping data'"'"'s entry is responsive to at least one merged cyclegroup comprising a plurality of cyclegroups.

29. The apparatus of claim 19, wherein said protection switch is located at one of said plurality of nodes other than said at least one of said plurality of nodes having the failed central switch.