Extending SONET/SDH automatic protection switching

• US 20050141415A1
• Filed: 02/15/2005
• Published: 06/30/2005
• Est. Priority Date: 12/05/1997
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Broberg, Robert, Getchell, David A.
• Granted Patent: US 7,570,583 B2
• Time in Patent Office: Days
• US Class Current: 370/223
• CPC Class Codes: H04J 2203/006 Fault tolerance and recovery
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability

Abstract

The invention provides a method and system for coupling a SONET/SDH network to a routing network that does not have a single point of failure. Multiple routers are coupled between the SONET/SDH network and the routing network, one for each data path; for example, a first router for the working data path and a second router for the protection data path. The routers intercommunicate to force APS to switch data paths bidirectionally, so as to allow only a single router for each data path.

Claims

1-17. -17. (canceled)

18. A method for communicatively coupling a first network to a second network by using a first device and a second device, the method comprising the steps of:

causing data to be transmitted over a first bidirectional data path but not over a second bidirectional data path, wherein;

said first bidirectional data path communicatively couples said first device to said second network;

said first device is communicatively coupled to said first network;

said second bidirectional data path communicatively couples said second device to said second network;

said second device is communicatively coupled to said first network;

said first network is associated with a first network type, said second network is associated with a second network type, and said first network type is different than said second network type;

based on transmitting said data over said first bidirectional data path, determining that one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

causing said data to no longer be transmitted over said first bidirectional data path; and

causing said data to be transmitted over said second bidirectional data path but not over said first bidirectional data path.

19. A method as recited in claim 18, wherein:

said first bidirectional data path includes a first unidirectional sending data path and a first unidirectional receiving data path;

said first bidirectional data path is used for transmitting data between said first network and said second network;

said second bidirectional data path includes a second unidirectional sending data path and a second unidirectional receiving data path;

said second bidirectional data path is used for transmitting information for use in determining that the one or more criteria are satisfied;

the first network type is a SONET network type;

the second network type is not SONTET network type; and

the method further comprising the steps of;

in response to determining that said one or more criteria are satisfied, causing said second device to send a command to said first device over a third data path; and

wherein in response to receiving said command, said first device no longer transmits said data over said first bidirectional data path.

20. A method as recited in claim 18, wherein;

said first bidirectional data path is designated as a working data path;

said second bidirectional data path is designated as a protection data path;

said first device is a first router;

said second device is a second router;

said first network type is a routing network type;

said second network type is a SONET/SDH network type; and

said one or more criteria are selected from the group consisting of (a) a first criterion that indicates a failure of a particular data path over which said data is being transmitted and (b) a second criterion that indicates an unacceptable degradation in transmitting said data over said particular data path.

21. A method as recited in claim 18, further comprising the steps of:

based on transmitting said data over said second bidirectional data path, determining that said one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

causing said data to no longer be transmitted over said second bidirectional data path; and

causing said data to be transmitted over first second bidirectional data path but not over said second bidirectional data path.

22. A method as recited in claim 18, wherein:

said first bidirectional data path includes a first unidirectional sending data path and a first unidirectional receiving data path;

the step of causing data to be transmitted over said first bidirectional data path but not over said second bidirectional data path includes the steps of;

causing said data to be transmitted from said first device to said second network over said first unidirectional sending data path; and

causing said data to be transmitted from said second network to said first device over said first unidirectional receiving data path;

said second bidirectional data path includes a second unidirectional sending data path and a second unidirectional receiving data path; and

the step of causing said data to be transmitted over said second bidirectional data path but not over said first bidirectional data path includes the steps of;

causing said data to be transmitted from said first device to said second network over said second unidirectional sending data path; and

causing said data to be transmitted from said second network to said first device over said second unidirectional receiving data path.

23. A method as recited in claim 18, wherein said data is first data, and the method further comprises the steps of:

causing second data to be transmitted over a third bidirectional data path but not over said second bidirectional data path, wherein said third bidirectional data path communicatively couples a third device to said second network;

based on transmitting said second data over said third bidirectional data path, determining that said one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

causing said second data to no longer be transmitted over said third bidirectional data path; and

causing said second data to be transmitted over said second bidirectional data path but not over said third bidirectional data path.

24. An apparatus for communicatively coupling a first network to a second network by using a first device and a second device, the apparatus comprising:

means for causing data to be transmitted over a first bidirectional data path but not over a second bidirectional data path, wherein;

said first bidirectional data path communicatively couples said first device to said second network;

said first device is communicatively coupled to said first network;

said second bidirectional data path communicatively couples said second device to said second network;

said second device is communicatively coupled to said first network;

said first network is associated with a first network type, said second network is associated with a second network type, and said first network type is different than said second network type;

means for determining, based on transmitting said data over said first bidirectional data path, that one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

means for causing said data to no longer be transmitted over said first bidirectional data path; and

means for causing said data to be transmitted over said second bidirectional data path but not over said first bidirectional data path.

25. An apparatus as recited in claim 24, wherein:

said first bidirectional data path includes a first unidirectional sending data path and a first unidirectional receiving data path;

said first bidirectional data path is used for transmitting data between said first network and said second network;

said second bidirectional data path includes a second unidirectional sending data path and a second unidirectional receiving data path;

said second bidirectional data path is used for transmitting information for use in determining that the one or more criteria are satisfied;

the first network type is a SONET network type;

the second network type is not SONET network type; and

the apparatus further comprising;

means for causing, in response to determining that said one or more criteria are satisfied, said second device to send a command to said first device over a third data path; and

wherein in response to receiving said command, said first device no longer transmits said data over said first bidirectional data path.

26. An apparatus as recited in claim 24, wherein;

said first bidirectional data path is designated as a working data path;

said second bidirectional data path is designated as a protection data path;

said first device is a first router;

said second device is a second router;

said first network type is a routing network type;

said second network type is a SONET/SDH network type; and

said one or more criteria are selected from the group consisting of (a) a first criterion that indicates a failure of a particular data path over which said data is being transmitted and (b) a second criterion that indicates an unacceptable degradation in transmitting said data over said particular data path.

27. An apparatus as recited in claim 24, further comprising:

means for determining, based on transmitting said data over said second bidirectional data path, that said one or more criteria are satisfied;

means for causing, in response to determining that said one or more criteria are satisfied, said data to no longer be transmitted over said second bidirectional data path; and

means for causing, in response to determining that said one or more criteria are satisfied, said data to be transmitted over first second bidirectional data path but not over said second bidirectional data path.

28. An apparatus as recited in claim 24, wherein:

said first bidirectional data path includes a first unidirectional sending data path and a first unidirectional receiving data path;

the means for causing data to be transmitted over said first bidirectional data path but not over said second bidirectional data path includes;

means for causing said data to be transmitted from said first device to said second network over said first unidirectional sending data path; and

means for causing said data to be transmitted from said second network to said first device over said first unidirectional receiving data path;

said second bidirectional data path includes a second unidirectional sending data path and a second unidirectional receiving data path; and

the means for causing said data to be transmitted over said second bidirectional data path but not over said first bidirectional data path includes;

means for causing said data to be transmitted from said first device to said second network over said second unidirectional sending data path; and

2

means for causing said data to be transmitted from said second network to said first device over said second unidirectional receiving data path.

29. An apparatus as recited in claim 24, wherein said data is first data, and the apparatus further comprises:

means for causing second data to be transmitted over a third bidirectional data path but not over said second bidirectional data path, wherein said third bidirectional data path communicatively couples a third device to said second network;

means for determining, based on transmitting said second data over said third bidirectional data path, that said one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

means for causing said second data to no longer be transmitted over said third bidirectional data path; and

means for causing said second data to be transmitted over said second bidirectional data path but not over said third bidirectional data path.

30. An apparatus for communicatively coupling a first network to a second network by using a first device and a second device, the apparatus comprising:

a network interface that is communicatively coupled to at least one of said first network and said second network for receiving one or more packet flows therefrom;

a processor;

one or more stored sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of;

causing data to be transmitted over a first bidirectional data path but not over a second bidirectional data path, wherein;

said first bidirectional data path communicatively couples said first device to said second network;

said first device is communicatively coupled to said first network;

said second bidirectional data path communicatively couples said second device to said second network;

said second device is communicatively coupled to said first network;

said first network is associated with a first network type, said second network is associated with a second network type, and said first network type is different than said second network type;

based on transmitting said data over said first bidirectional data path, determining that one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

causing said data to no longer be transmitted over said first bidirectional data path; and

causing said data to be transmitted over said second bidirectional data path but not over said first bidirectional data path.

31. An apparatus as recited in claim 30, wherein:

said first bidirectional data path includes a first unidirectional sending data path and a first unidirectional receiving data path;

said first bidirectional data path is used for transmitting data between said first network and said second network;

said second bidirectional data path includes a second unidirectional sending data path and a second unidirectional receiving data path;

said second bidirectional data path is used for transmitting information for use in determining that the one or more criteria are satisfied;

the first network type is a SONET network type;

the second network type is not SONET network type; and

the apparatus further comprising one or more stored sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of;

in response to determining that said one or more criteria are satisfied, causing said second device to send a command to said first device over a third data path; and

wherein in response to receiving said command, said first device no longer transmits said data over said first bidirectional data path.

32. An apparatus as recited in claim 30, wherein;

said first bidirectional data path is designated as a working data path;

said second bidirectional data path is designated as a protection data path;

said first device is a first router;

said second device is a second router;

said first network type is a routing network type;

said second network type is a SONET/SDH network type; and

said one or more criteria are selected from the group consisting of (a) a first criterion that indicates a failure of a particular data path over which said data is being transmitted and (b) a second criterion that indicates an unacceptable degradation in transmitting said data over said particular data path.

33. An apparatus as recited in claim 30, further comprising one or more stored sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of:

based on transmitting said data over said second bidirectional data path, determining that said one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

causing said data to no longer be transmitted over said second bidirectional data path; and

causing said data to be transmitted over first second bidirectional data path but not over said second bidirectional data path.

34. An apparatus as recited in claim 30, wherein:

said first bidirectional data path includes a first unidirectional sending data path and a first unidirectional receiving data path;

the one or more stored sequences of instructions for causing data to be transmitted over said first bidirectional data path but not over said second bidirectional data path includes one or more stored sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of;

causing said data to be transmitted from said first device to said second network over said first unidirectional sending data path; and

causing said data to be transmitted from said second network to said first device over said first unidirectional receiving data path;

said second bidirectional data path includes a second unidirectional sending data path and a second unidirectional receiving data path; and

the one or more stored sequences of instructions for causing said data to be transmitted over said second bidirectional data path but not over said first bidirectional data path includes one or more stored sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of;

causing said data to be transmitted from said first device to said second network over said second unidirectional sending data path; and

causing said data to be transmitted from said second network to said first device over said second unidirectional receiving data path.

35. An apparatus as recited in claim 30, wherein said data is first data, and the apparatus further comprises one or more stored sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of:

causing second data to be transmitted over a third bidirectional data path but not over said second bidirectional data path, wherein said third bidirectional data path communicatively couples a third device to said second network;

based on transmitting said second data over said third bidirectional data path, determining that said one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

causing said second data to no longer be transmitted over said third bidirectional data path; and

causing said second data to be transmitted over said second bidirectional data path but not over said third bidirectional data path.

36. A system for communicatively coupling a first network to a second network, the system comprising:

a first device that is communicatively coupled to said second network through a first bidirectional data path, wherein said first device is communicatively coupled to said first network;

a second device that is communicatively coupled to said second network through a second bidirectional data path, wherein said second device is communicatively coupled to said first network;

wherein;

said first network is associated with a first network type, said second network is associated with a second network type, and said first network type is different than said second network type;

said first device is configured to transmit data over said first bidirectional data path but said second device is not configured to transmit said data over said second bidirectional data path;

said second device is configured to;

determine, based on said data that is transmitted over said first bidirectional data path, that one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

cause said data to no longer be transmitted over said first bidirectional data path; and

cause said data to be transmitted over said second bidirectional data path but not over said first bidirectional data path.

37. A system as recited in claim 36, wherein:

said first bidirectional data path includes a first unidirectional sending data path and a first unidirectional receiving data path;

said first bidirectional data path is used for transmitting data between said first network and said second network;

said second bidirectional data path includes a second unidirectional sending data path and a second unidirectional receiving data path;

said second bidirectional data path is used for transmitting information for use in determining that the one or more criteria are satisfied;

the first network type is a SONET network type;

the second network type is not SONET network type;

said second device is configured to send, in response to determining that said one or more criteria are satisfied, a command to said first device over a third data path; and

said first device is configured to, in response to receiving said command, no longer transmit said data over said first bidirectional data path.

38. A system as recited in claim 36, wherein;

said first bidirectional data path is designated as a working data path;

said second bidirectional data path is designated as a protection data path;

said first device is a first router;

said second device is a second router;

said first network type is a routing network type;

said second network type is a SONET/SDH network type; and

said one or more criteria are selected from the group consisting of (a) a first criterion that indicates a failure of a particular data path over which said data is being transmitted and (b) a second criterion that indicates an unacceptable degradation in transmitting said data over said particular data path.

39. A system as recited in claim 36, wherein:

said first device is configured to;

determine, based on said data being transmitted over said second bidirectional data path, that said one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

cause said data to no longer be transmitted over said second bidirectional data path; and

cause said data to be transmitted over first second bidirectional data path but not over said second bidirectional data path.

40. A system as recited in claim 36, wherein:

said first bidirectional data path includes a first unidirectional sending data path and a first unidirectional receiving data path;

said first device being configured to transmit said data over a first bidirectional data path includes being configured to transmit said data to said second network over said first unidirectional sending data path and to receive said data from said second network over said first unidirectional receiving data path;

said second bidirectional data path includes a second unidirectional sending data path and a second unidirectional receiving data path; and

said second device being configured to transmit said data over said second bidirectional data path includes being configured to transmit said data to said second network over said second unidirectional sending data path and to receive said data from said second network over said second unidirectional receiving data path.

41. A system as recited in claim 36, wherein said data is first data and the system further comprises:

a third device that is communicatively coupled to said second network through a third bidirectional data path, wherein said third device is communicatively coupled to said first network;

wherein;

said third device is configured to transmit second data over said third bidirectional data path but said second device is not configured to transmit said second data over said second bidirectional data path;

said second device is configured to;

determine, based on said second data that is transmitted over said third bidirectional data path, that one or more criteria are satisfied;

in response to determining that said one or more criteria are satisfied,

cause said second data to no longer be transmitted over said third bidirectional data path; and

cause said second data to be transmitted over said second bidirectional data path but not over said third bidirectional data path.

42. A method comprising the steps of:

providing a bidirectional data path in a first network, wherein said bidirectional data path includes;

a first unidirectional data path that communicatively couples a first set of routers; and

a second unidirectional data path that communicatively couples a second set of routers;

wherein;

said first set of routers having at least one router not in said second set of routers;

at least one router in said first set of routers communicating with at least one router in said second set of routers using a third path;

said first unidirectional data path communicatively couples a first router to a second network; and

said second unidirectional data path communicatively couples a second router to said second network.

43. A method as recited in claim 42, wherein said first network includes a routing network and said second network includes a SONET/SDH network.

44. A router, comprising:

connections for receiving and transmitting data using a bidirectional data path between said router and at least one other router; and

a processor for routing said data, said processor programmed to ensure that said bidirectional data path includes a first unidirectional data path that communicatively couples a first set of routers and a second unidirectional data path that communicatively couples a second set of routers, said first set of routers having at least one router not in said second set of routers, and at least one router in said first set of routers communicating with at least one router in said second set of routers using a third path, wherein;

said first unidirectional data path communicatively couples a first router to a second network; and

said second unidirectional data path communicatively couples a second router to said second network.

45. A router as in claim 44, wherein said first network includes a routing network and said second network includes a SONET/SDH network.