Extending SONET/SDH automatic protection switching

• US 7,570,583 B2
• Filed: 02/15/2005
• Issued: 08/04/2009
• Est. Priority Date: 12/05/1997
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Broberg, Robert, Getchell, David A.
• Primary Examiner(s): Trost, IV; William
• Assistant Examiner(s): Nguyen; Toan D
• Application Number:
  US11/059,484
• Publication Number:
  US 20050141415A1
• Time in Patent Office: 1,631 Days
• Field of Search: 370/217, 370/219, 370/220, 370/227
• US Class Current: 370/219
• 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. 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 first data to be transmitted and second data to be received 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 first data and receiving said second 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 first data to no longer be transmitted and said second data to no longer be received over said first bidirectional data path; and

causing said first data to be transmitted and said second data to be received over said second bidirectional data path but not over said first bidirectional data path;

based on transmitting said first data and receiving said second 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 first data to no longer be transmitted and said second data to no longer be received over said second bidirectional data path; and

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

2. The method as recited in claim 1, 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 and receiving 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 and receiving 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 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 first data and no longer receives said second data over said first bidirectional data path.

3. The method as recited in claim 1, 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 first data is being transmitted and said second data is being received and (b) a second criterion that indicates an unacceptable degradation in transmitting said first data and receiving said second data over said particular data path.

4. The method as recited in claim 1, wherein:

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

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

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

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

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

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

5. The method as recited in claim 1, further comprising the steps of:

causing third data to be transmitted and fourth data to be received 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 third data and receiving said fourth 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 third data to no longer be transmitted and said fourth data to no longer be received over said third bidirectional data path; and

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

6. 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 first data to be transmitted and second data to be received 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 first data and receiving said second 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 first data to no longer be transmitted and said second data to no longer be received over said first bidirectional data path; and

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

means for determining, based on transmitting said first data and receiving said second 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 first data to no longer be transmitted and said second data to no longer be received over said second bidirectional data path; and

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

7. The apparatus as recited in claim 6, 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 and receiving 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 and receiving 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 first data and no longer receives said second data over said first bidirectional data path.

8. The apparatus as recited in claim 6, 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 first data is being transmitted and said second data is being received and (b) a second criterion that indicates an unacceptable degradation in transmitting said first data and receiving said second data over said particular data path.

9. The apparatus as recited in claim 6, wherein:

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

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

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

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

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

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

10. An The apparatus as recited in claim 6, further comprising:

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

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

11. A network equipment element configured for communicatively coupling a first network to a second network by using a first device and a second device, and configured to perform:

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

causing said first data to be transmitted and said second data to be received over said second bidirectional data path but not over said first bidirectional data path;

based on transmitting said first data and receiving said second 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 first data to no longer be transmitted and said second data to no longer be received over said second bidirectional data path; and

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

12. The network equipment element as recited in claim 11, 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 and receiving 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 and receiving 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 network equipment element configured to perform;

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 first data and no longer receives said second data over said first bidirectional data path.

13. The network equipment element as recited in claim 11, 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 first data is being transmitted and said second data is being received and (b) a second criterion that indicates an unacceptable degradation in transmitting said first data and receiving said second data over said particular data path.

14. The network equipment element as recited in claim 11, wherein:

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

further said network equipment element is further configured to perform;

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

causing said second data to be received 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

further said network equipment element is further configured to perform;

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

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

15. The network equipment element as recited in claim 11, further configured to perform:

causing third data to be transmitted and fourth data to be received 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 third data and receiving said fourth 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 third data to no longer be transmitted and said fourth data to no longer be received over said third bidirectional data path; and

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

16. 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 first data and receive second data over said first bidirectional data path but said second device is not configured to transmit first data or receive second data said data over said second bidirectional data path;

said second device is configured to;

determine, based on said first data that is transmitted and said second data that is received 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 first data to no longer be transmitted and said second data to no longer be received over said first bidirectional data path; and

cause said first data to be transmitted and said second data to be received over said second bidirectional data path but not over said first bidirectional data path;

said first device is configured to;

determine, based on said first data that is transmitted and said second data that is received 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 first data to no longer be transmitted and said second data to no longer be received over said second bidirectional data path; and

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

17. The system as recited in claim 16, 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 and receiving 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 and receiving 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 first data and no longer receive said second data over said first bidirectional data path.

18. The system as recited in claim 16, 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 first data is being transmitted and said second data is being received and (b) a second criterion that indicates an unacceptable degradation in transmitting said first data and receiving said second data over said particular data path.

19. The system as recited in claim 16, 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 first data and receive said second data over a first bidirectional data path includes being configured to transmit said first data to said second network over said first unidirectional sending data path and to receive said second 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 first data and receive said second data over said second bidirectional data path includes being configured to transmit said first data to said second network over said second unidirectional sending data path and to receive said second data from said second network over said second unidirectional receiving data path.

20. The system as recited in claim 16, further comprising:

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 third data and receive fourth data over said third bidirectional data path but said second device is not configured to transmit said third data or receive fourth data over said second bidirectional data path;

said second device is configured to;

determine, based on said third data that is transmitted and said fourth data that is received 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 third data to no longer be transmitted and said fourth data to no longer be received over said third bidirectional data path; and

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