Granted Patent B2

US 8,243,743 · App. 12/421,227 · Granted Aug 14, 2012

Abstract

Claims (47)

1. A method for in-band protection switch signaling in a communication system, the communication system arranged as a point-to-multipoint tree, the point-to-multipoint tree including a root node communicatively coupled to a plurality of leaf nodes through both a working link and a protection link, the method comprising:

transferring data through a current link of the point-to-multipoint tree, the current link being one of the working link and the protection link;

detecting, by a leaf node, a fault in the current link of the point-to-multipoint tree;

in response to detecting the fault, setting a remote defect indicator (RDI) flag in a continuity check message (CCM) at the leaf node;

transmitting the CCM to the root node;

in response to receiving the CCM, notifying, by the root node, each other leaf node in the point-to-multipoint tree of the fault using the current link, the notifying via continuity check messages to the leaf nodes, each continuity check message including an automatic protection switching type-length-value (TLV), a TLV having a protection group identifier identifying a subset of the leaf nodes according to a service associated with the subset; and

switching the root node and each leaf node to the other link of the working link and the protection link.

2. The method of claim 1 , wherein switching the root node and each leaf node to the other link of the working link and the protection link comprises altering a backbone virtual local area network identifier (“B-VID”) value in a backbone service instance table.

3. The method of claim 1 , wherein the root node detects the fault in the current link, the method further comprises:

setting a remote defect indicator flag in a plurality of continuity check messages; and

transmitting the plurality of continuity check messages to the leaf nodes using the current link.

4. The method of claim 1 , wherein the automatic protection switching TLV includes:

a signal fail on current link indicator.

5. The method of claim 1 , wherein the leaf node detects the fault in the current link by determining that the leaf node has not received a continuity check message from the root node within a predetermined amount of time.

6. The method of claim 3 , wherein the root node detects the fault in the current link by determining that the root node has not received a continuity check message from at least one leaf node within a predetermined amount of time.

7. A method for in-band protection switch signaling in a communication system, the communication system arranged as a point-to-multipoint tree, the point-to-multipoint tree including a root node communicatively coupled to a plurality of leaf nodes through both a working link and a protection link, the communication system including an element management system managing at least one leaf node of the point-to-multipoint tree, the method comprising:

receiving a management system request from the element management system, the management request including a notification of a fault in the current link of the point-to-multipoint tree;

evaluating the management system request to determine whether the communication system is allowed to implement the management system request;

responsive to determining that the communication system is allowed to implement the management system request, notifying, by the root node, each leaf node in the point-to-multipoint tree of the management request using the current link, the notifying via continuity check messages to the leaf nodes, each continuity check message including an automatic protection switching type-length-value (TLV), a TLV having a protection group identifier identifying a subset of the leaf nodes according to a service associated with the subset; and

executing the management system request.

8. The method of claim 7 , wherein the automatic protection switching TLV includes:

at least one request value representing one command of a set of management commands, each request value corresponding to one of the protection group identifiers.

9. The method of claim 7 , wherein the management system request is one of a force switch (FS), a lockout of protection (LoP), and a manual switch (MS) instruction.

10. The method of claim 8 , wherein the set of management commands includes at least one of lockout of protection, force switch to protection, signal fail on protection, signal fail on working, manual switch to protection and manual switch to working.

11. The method of claim 8 , wherein the request value has a 4-bit length, the protection group identifier is determined by a position of the 4-bit request value within the automatic protection switching TLV.

12. A communication system arranged as a point-to-multipoint tree, the communication system comprising:

a root node;

a plurality of leaf nodes;

a working link, the working link including a first set of core nodes, the first set of core nodes communicatively coupled between the root node and the plurality of leaf nodes; and

a protection link, the protection link including a second set of core nodes, the second set of core nodes exclusive of the first set of core nodes, the second set of core nodes communicatively coupled between the root node and the plurality of leaf nodes;

the root node operable to:

receive from a leaf node a continuity check message (CCM) with a remote defect indicator (RDI) flag that is set by the leaf node in response to detecting a fault in the current link at the leaf node;

notify, via the root node, each other leaf node in the tree of the fault using the current link, the notifying via continuity check messages to the leaf nodes, each continuity check message including an automatic protection switching type-length-value (TLV), a TLV having a protection group identifier identifying a subset of the leaf nodes according to a service associated with the subset; and

switch to the other link of the working link and the protection link; each leaf node being operable to:

receive a notification of the fault; and

switch to the other link of the working link and the protection link.

13. The communication system of claim 12 , wherein the root node is further operable to notify each leaf node in the tree of the fault by:

setting a remote defect indicator flag in a plurality of continuity check messages; and

transmitting the plurality of continuity check messages to the leaf nodes using the current link.

14. The communication system of claim 12 , further comprising:

an element management system managing at least one node of the tree, the managed node operable to:

receive a management system request from the element management system;

evaluate the management system request to determine whether the communication system is allowed to implement the management system request; and

responsive to determining that the communication system is allowed to implement the management system request, notify each node in the tree of the management request.

15. The communication system of claim 14 , wherein the managed node is a leaf node,

the leaf node notifies each node in the tree about the management request by using the root node as a proxy for the managed leaf node; and

the root node is further operable to forward the management request to all other leaf nodes in the tree.

Assignments (8)