| Title: |
Methods and Arrangement in a MPLS-TP Telecommunications Network for OAM Functions |
| Document Number: |
20120163190 |
| Publication Date: |
June 28, 2012 |
| Appl. No: |
13/386174 |
| Application Filed: |
July 24, 2009 |
| Abstract: |
Extensions to a Multi-Protocol Label Switching (MPLS) frame forwarding procedure in an MPLS node are described. A context descriptor is defined for each frame received on a connection terminated at that node, and where this context descriptor is provided together with the frame to a corresponding function (e.g. Operations, Administration and Maintenance, OAM) if needed. The context descriptor is constructed based on key attributes characterizing the terminated connection, over which the frame is received, and addresses a particular function endpoint (Maintenance Endpoints (MEPs), Selector Bridge of a protection instance etc.) of a corresponding function (OAM, protection, etc.). In one embodiment, a Multi-Protocol Label Switching (MPLS) node is directed to check not only the first but also the second label, and not to drop the first label (and the label space if relevant) when the second label is the Generic Association Channel Label (GAL). In this way, the original context of the packet is kept (i.e. the information relating to the connection over which the packet was received), and can be used for de-multiplexing to the corresponding MEP. Then the identifiers within the OAM payload can be used for verification of the connectivity. Other embodiments describe alternative solutions. |
| Inventors: |
Jocha, Dávid (Budapest, HU); Kern, András (Budapest, HU) |
| Claim: |
1.-17. (canceled) |
| Claim: |
18. A method in a node of a Multi-Protocol Label Switching (MPLS) telecommunications network, the method comprising the steps of: receiving a MPLS frame, the MPLS frame having a label stack comprising a first label and a second label; determining whether the frame has reached its terminating node and, if so; checking the second label in the label stack to determine whether the second label relates to a Generic Associated Channel Label (GAL) and, if so; storing a context descriptor constructed based on key attributes characterizing the terminated connection over which the frame has been received, for use by an operations, administration, and maintenance (OAM) function during subsequent processing of the frame when performing connection verification (CV), continuity checking (CC), or other functions where the identity of the origin of the frame is required; routing the frame for Generic Associated Channel Header (G-ACH) processing. |
| Claim: |
19. The method of claim 18 wherein the determining whether the frame has reached its terminating node comprises checking the first label in the label stack. |
| Claim: |
20. The method of claim 19 wherein the checking the first label in the label stack comprises checking whether the first label is associated with a pop operation. |
| Claim: |
21. The method of claim 18 wherein the determining whether the frame has reached its terminating node comprises checking time-to-live (TTL) information received with the frame. |
| Claim: |
22. The method of claim 18 wherein the storing the context descriptor comprises storing the first label for future processing by the OAM function. |
| Claim: |
23. The method of claim 22 wherein the storing the context descriptor further comprises storing label space information. |
| Claim: |
24. The method of claim 23 wherein the storing the context descriptor comprises: storing the first label and label space information prior to the second label being checked: retaining the first label and label space information if the second label is a GAL; dropping the first label and label space information if the second label is not a GAL. |
| Claim: |
25. The method of claim 23 wherein the storing the context descriptor comprises storing the first label and the label space information after determining that the second label is a GAL. |
| Claim: |
26. The method of claim 22 wherein the storing the context descriptor comprises storing the last processed label in a memory as a label stack history. |
| Claim: |
27. The method of claim 18 wherein the checking the second label is performed in response to a status bit being set in the received frame, the status bit indicating that the connection is a monitored connection. |
| Claim: |
28. The method of claim 18 wherein the context descriptor is stored based on information provided in a label space of the received MPLS frame, wherein a label space is allocated to each monitored connection. |
| Claim: |
29. The method of claim 28 wherein a separate incoming label map (ILM) table is provided for each label space. |
| Claim: |
30. The method of claim 28 wherein a label space for a monitored connection is used to address a Maintenance EndPoint (MEP). |
| Claim: |
31. The method of claim 18 wherein storing the context descriptor comprises storing the context descriptor using a next hop label forwarding entry (NHFLE) key. |
| Claim: |
32. The method of claim 18 further comprising: de-multiplexing the received frame to obtain data relating to OAM functions; routing the frame to a Maintenance Endpoint (MEP) based on routing information contained in the de-multiplexed data; performing a connectivity check using the stored context descriptor. |
| Claim: |
33. A node of a Multi-Protocol Label Switching (MPLS) telecommunications network, the node comprising: receiving circuitry operative to receive a MPLS frame, the MPLS frame having a label stack comprising a first label and a second label; processing circuitry operatively connected to the receiving circuitry and configured to: determine whether the frame has reached its terminating node and, if so; check the second label in the label stack to determine whether the second label relates to a Generic Associated Channel Label (GAL) and, if so: store a context descriptor constructed based on key attributes characterizing the terminated connection over which the frame has been received, for use by an operations, administration, and maintenance (OAM) function during subsequent processing of the frame when performing connection verification (CV), continuity checking (CC) or other functions where the identity of the origin of the frame is required; route the frame for Generic Associated Channel Header (G-ACH) processing. |
| Claim: |
34. The node of claim 33 wherein the processing circuitry is configured to determine whether the frame has reached its terminating node by checking the first label in the label stack. |
| Claim: |
35. The node of claim 34 the processing circuitry is configured to determine whether the frame has reached its terminating node by checking whether the first label is associated with a pop operation. |
| Claim: |
36. The node of claim 33 wherein the processing circuitry is configured to determine whether the frame has reached its terminating node by checking time-to-live (TTL) information received with the frame. |
| Claim: |
37. The node of claim 33 wherein the processing circuitry is configured to store the context descriptor such that storing the context descriptor comprises storing the first label for future processing by the OAM function. |
| Claim: |
38. The node of claim 37 wherein the processing circuitry is configured to store the context descriptor such that storing the context descriptor comprises storing label space information. |
| Claim: |
39. The node of claim 38 wherein the processing circuitry is configured to store the context descriptor such that storing the context descriptor comprises: storing the first label and label space information prior to the second label being checked: retaining the first label and label space information if the second label is a GAL; dropping the first label and label space information if the second label is not a GAL. |
| Claim: |
40. The node of claim 38 wherein the processing circuitry is configured to store the context descriptor such that storing the context descriptor comprises storing the first label and the label space information after determining that the second label is a GAL. |
| Claim: |
41. The node of claim 37 wherein the processing circuitry is configured to store the context descriptor such that storing the context descriptor comprises storing the last processed label in a memory as a label stack history. |
| Claim: |
42. The node of claim 33 wherein the processing circuitry is configured to check the second label such that checking the second label is performed in response to a status bit being set in the received frame, the status bit indicating that the connection is a monitored connection. |
| Claim: |
43. The node of claim 33 wherein the processing circuitry is configured to store the context descriptor based on information provided in a label space of the received MPLS frame, wherein a label space is allocated to each monitored connection. |
| Claim: |
44. The node of claim 43 wherein the processing circuitry is configured to provide a separate incoming label map (ILM) table for each label space. |
| Claim: |
45. The node of claim 43 wherein the processing circuitry is configured to use a label space for a monitored connection to address a Maintenance EndPoint (MEP). |
| Claim: |
46. The node of claim 33 wherein the processing circuitry is configured to store the context descriptor such that storing the context descriptor comprises storing the context descriptor using a next hop label forwarding entry (NHFLE) key. |
| Claim: |
47. The node of claim 33 wherein the processing circuitry is further configured to: de-multiplex the received frame to obtain data relating to OAM functions; route the frame to a Maintenance Endpoint (MEP) based on routing information contained in the de-multiplexed data; perform a connectivity check using the stored context descriptor. |
| Current U.S. Class: |
3702/411 |
| Current International Class: |
04 |
| Accession Number: |
edspap.20120163190 |
| Database: |
USPTO Patent Applications |
