Dynamic bandwidth adjustment in packet transport network

1. A method for adjusting bandwidth in a communications network, the network including a plurality of nodes connected over multiple links and a plurality of services running on the links, the method comprising the steps of:

detecting an impairment of a link, the impairment invoking a reduction in bandwidth available to the services running on the link;

communicating information about the impairment to other nodes in the network; and

redistributing services between the links to limit a bandwidth required by services running on the impaired link to a value not exceeding the bandwidth available on the impaired link,

wherein the redistributing is on a per service basis, and

wherein the redistributing comprises routing a service from the impaired link to another link and routing a service from the another link to the impaired link.

2. The method of claim 1 , further comprising:

detecting a reduction in the link impairment, the reduction resulting in the impaired link regaining its original bandwidth; and

returning the redistributed services to their original paths.

3. The method of claim 1 , further comprising:

redistributing real-time services.

4. The method of claim 3 , further comprising:

redistributing best effort services.

5. The method of claim 1 , further comprising:

specifying a threshold value for a link buffer data;

redistributing at least one service from a path associated with the link if buffer data exceeds the threshold.

6. The method of claim 5 , wherein the threshold value is a specified percentage of the link bandwidth.

7. The method of claim 1 , wherein the information about the impairment includes bandwidth of the impaired link.

8. The method of claim 1 , further comprising:

communicating changes in the network resulting from the re-distribution to a control plane or network management system.

9. A node in a communications network, the network including a plurality of nodes connected over multiple links and a plurality of services running on the links, the node comprising:

an impairment detection module for detecting an impairment in a link used by the node, the impairment invoking a reduction in bandwidth available to the services running on the link;

a communication interface for communicating information about the impairment to other nodes in the network; and

an impairment resolution module for redistributing services between the impaired link and at least one other link,

wherein the redistributing is on a per service basis, and

wherein the redistributing comprises routing a service from the impaired link to another link and routing a service from the another link to the impaired link.

10. The node of claim 9 , wherein the communication interface provides communication between the impairment detection module and the impairment resolution module.

11. The node of claim 9 , wherein the reduced bandwidth resulting from link impairment is greater than a bandwidth required by the redistributed services.

12. The node of claim 9 , wherein the communication interface comprises:

a first functional unit for providing communication between the impaired link and other nodes in the network; and

a second functional unit for providing communication between the impairment detection module and the impairment resolution module.

13. The node of claim 9 , wherein the communication interface communicates information on services running on the impaired link.

14. The node of claim 9 , wherein the communication interface receives available bandwidth information from the other nodes, the available bandwidth information corresponding to links being used by the other nodes.

15. The node of claim 14 , wherein the communication interface receives service information for services running the links.

16. The node of claim 9 , wherein the impairment detection module, the communication interface and the impairment resolution module are implemented as one hardware module.

17. The node of claim 9 , where each of the impairment detection module, the communication interface and the impairment resolution module are implemented as separate hardware modules.