MAINTENANCE FRIENDLY OPTICAL FIBER SWITCHING SYSTEM

• US 20110116789A1
• Filed: 11/13/2009
• Published: 05/19/2011
• Est. Priority Date: 11/13/2009
• Status: Active Grant

• Current Assignee: Verizon Patent and Licensing Incorporated (Verizon Communications Inc.)
• Original Assignee: Verizon Patent and Licensing Incorporated (Verizon Communications Inc.)
• Inventors: WELLBROCK, Glenn A., XIA, Tiejun J.
• Granted Patent: US 8,391,707 B2
• Time in Patent Office: Days
• US Class Current: 398/5
• CPC Class Codes: H04J 14/021 Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
• CPC Class Codes: H04J 14/0279 WDM point-to-point architectures
• CPC Class Codes: H04J 14/0291 Shared protection at the optical multiplex section (1:1, n:m)
• CPC Class Codes: H04J 14/0295 Shared protection at the optical channel (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 2011/0083 Testing; Monitoring

Abstract

First and second switching device are connected by a number of signal paths. The first switching device receives an instruction to switch from a first one of the signal paths to a second one of the signal paths. The first switching device performs, in response to the received instruction, a first switching operation to connect the first path, at an input of the first switching device, to the second path, at an output of the first switching device. The second switching device receives the instruction to switch from the first path to the second path and detects a loss of signal on the first path as a result of the first switching operation performed by the first switching device. The second device performs, in response to detecting the loss of signal on the first path, a second switching operation to connect the first path, at an output of the second switching device, to the second path, at an input of the second switching device.

Claims

1. A system comprising:

a plurality of switching devices, a first switching device, of the plurality of switching devices, connected to a second switching device, of the plurality of switching devices, by a plurality of signal paths,

the first switching device is to;

receive an instruction to switch from a first path, of the plurality of signal paths, to a second path, of the plurality of signal paths, where the first path is different from the second path, and

perform, in response to the received instruction, a first switching operation to connect the first path, at an input of the first switching device, to the second path, at an output of the first switching device; and

the second switching device is to;

receive the instruction to switch from the first path to the second path,

detect a loss of signal on the first path as a result of the first switching operation performed by the first switching device, and

perform, in response to detecting the loss of signal on the first path, a second switching operation to connect the first path, at an output of the second switching device, to the second path, at an input of the second switching device.

2. The system of claim 1, where the first switching device is further to:

connect the second path to a first test device before performing the first switching operation, and

transmit a test signal, from the first test device, on the second path; and

where the second switching device is further to;

connect the second path to a second test device before performing the second switching operation,

receive the test signal on the second path, and

provide the test signal to the second test device to determine a suitability of the second path to handle signals from the first path.

3. The system of claim 2, where the first switching device and the second switching device are to perform the first switching operation and the second switching operation, respectively, only when the second path is determined to be suitable to handle the signals from the first path.

4. The system of claim 3, further comprising:

a network management device, connected to the first test device and the second test device, to;

receive, from the second test device, information associated with the received test signal, and

determine, from the information associated with the received test signal, whether the second path is suitable to handle signals from the first path.

5. The system of claim 1, further comprising:

a network management device, connected to the first switching device and the second switching device, to generate and provide the instruction to the first switching device and the second switching device.

6. The system of claim 5, further comprising:

a first network device connected to the first switching device; and

a second network device connected to the second switching device;

where the network management device is to;

send a notification to the first network device and the second network device, where the notification instructs the first network device and the second network device to ignore a loss of signal while the first switching operation and the second switching operation are performed.

7. The system of claim 6, where the second network device is to initiate a protection measure when the first switching operation and the second switching operation collectively take more than a particular amount of time.

8. The system of claim 1, where the first switching operation and the second switching operation are both completed in less than approximately 20 ms.

9. The system of claim 1, where the second switching operation is completed in less than approximately 10 ms after detecting the loss of signal on the first path.

10. The system of claim 1, where the first switching operation is completed in less than approximately 10 ms in response to the received instruction to switch from the first path to the second path.

11. The system of claim 1, where a maintenance operation is performed on the first path to form a maintained first path, and

where the first switching device is further to:

receive another instruction to switch from the second path to the maintained first path, and

perform, in response to the other instruction, a third switching operation to connect the first path, at the input of the first switching device, to the maintained first path, at the output of the first switching device; and

the second device is further to;

receive the other instruction to switch from the second path to the maintained first path,

detect a loss of signal on the second path as a result of the third switching operation performed by the first switching device, and

perform, in response to the loss of signal on the second path, a fourth switching operation to connect the first path, at the output of the second switching device, to the maintained first path, at the input of the second switching device.

12. A method comprising:

receiving, by a first switching device, of a plurality of switching devices, an instruction to switch from a first path, of a plurality of signal paths, to a second path, of the plurality of signal paths;

performing, by the first switching device, in response to the instruction, a first switching operation, within a particular period of time, to connect the first path, at an input of the first switching device, to the second path, at an output of the first switching device;

receiving, by a second switching device, of the plurality of switching devices, the instruction to switch from the first path to the second path, where the second switching device is connected to the first switching device by the plurality of optical signal paths; and

detecting, by the second switching device, a loss of signal from the first switching device, on the first path, as a result of the first switching operation.

performing, by the second switching device, in response the loss of signal on the first path, a second switching operation, within the particular period of time from when the loss of signal is detected, to connect the first path, at an output of the second switching device, to the second path, at an input to the second switching device.

13. The method of claim 12, further comprising:

completing, by the first switching device, the first switching operation in less than approximately 10 ms.

14. The method of claim 12, further comprising:

completing, by the second switching device, the second switching operation in less than approximately 10 ms from the time the loss of signal is detected.

15. The method of claim 12, further comprising:

completing, by the first switching device and the second switching device, the first switching operation and the second switching operation, respectively, in less than approximately 20 ms.

16. The method of claim 12, further comprising:

connecting, by the first switching device, to a first test device, before performing the first switching operation;

receiving, by the first switching device, a test signal, from the first test device, to test the suitability of the second path to handle signals from the first path;

transmitting, by the first switching device, the test signal, to the second switching device over the second path;

connecting, by the second switching device, to a second test device, before performing the second switching operation;

receiving, by the second switching device, a test signal from the first switching device, via the second path; and

sending, by the second switching device, the received test signal, to the second test device, to determine the suitability of the second path to carry signals from the first path.

17. The method of claim 12, where a maintenance operation is performed on the first path to form a maintained first path, of the plurality of signal paths, the method further comprising:

receiving, by the first switching device, another instruction to switch from the second path, to the maintained first path;

performing, by the first switching device, in response to the other instruction, a third switching operation, within the particular period of time to connect the first path, at the input of the first switching device, to the maintained first path, at the output of the first switching device;

receiving, by the second switching device, the other instruction to switch from the second path to the maintained first path; and

detecting, by the second switching device, a loss of signal from the first switching device, on the second path, as a result of the third switching operation; and

performing, by the second switching device, in response the loss of signal on the second path, a fourth switching operation, within the particular period of time from when the loss of signal is detected, to connect the first path, at the output of the second switching device, to the maintained first path, at the input to the second switching device.

18. A switching device of a plurality of switching devices in an optical network, the switching device comprising:

a switch to;

receive an instruction to switch from a working path, of a plurality of paths carrying optical network traffic, to a maintenance path, of the plurality of paths, where the working path includes one or more working fibers that carry optical network traffic and where the maintenance path includes one or more spare fibers not carrying optical network traffic,

determine, from the instruction, whether the switching device is a downstream switching device or an upstream switching device,

when the switching device is the downstream switching device, perform, in response to the received instruction, a first switching operation to connect the working path, at an input of the switch, to the maintenance path, at an output of the switch, and

when the switching device is the upstream switching device;

detect a loss of light associated with the optical network traffic on the working path as a result of a switching operation performed by a downstream switching device, and

perform, in response to the loss of light on the working path, a second switching operation to connect the working path, at an output of the switch, to the maintenance path at an input of the switch.

19. The switching device of claim 18, further comprising:

a test device to generate or receive a test signal;

where, when the switching device is the downstream switching device, the switch is to;

connect the maintenance path to the test device before performing the first switching operation, and

output the test signal, from the test device, on the maintenance path; and

where, when the switching device is the upstream switching device, the switch is to;

connect the maintenance path to the test device before performing the second switching operation,

receive the test signal on the maintenance path, and

provide the test signal to the test device to determine a suitability of the maintenance path to handle optical network traffic from the working path.

20. The switching device of claim 18, where the first switching operation is completed within 10 ms of commencing the first switching operation, and the second switching operation is completed within 10 ms of detecting the loss of light.