METHOD AND APPARATUS FOR NODE REALIGNMENT IN A TELECOMMUNICATIONS NETWORK

• US 20150244614A1
• Filed: 09/13/2012
• Published: 08/27/2015
• Est. Priority Date: 09/13/2012
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Deniele Carelli, Diego Caviglia, Paola Rebella
• Inventors: Rebella, Paolo, Ceccarelli, Daniele, Caviglia, Diego
• Granted Patent: US 9,686,188 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

A method of realigning a node in a label switched network comprising a plurality of nodes and a node with a processor, a memory, and a network interface, for carrying out the method. The method includes periodically maintaining backup path status information for the node., restarting the node, and re-establishing label switched paths with the plurality of nodes using the backup status information. Communication with adjacent nodes is carried out in order to reconcile the path status information with respective path status information in the adjacent nodes in order to establish node realignment preferably judged against a threshold value for path reliability.

Claims

1. A method of realigning a node in a label switched network comprising a plurality of nodes, the method comprising:

periodically maintaining backup path status information for the node;

in response to restarting of the node, re-establishing label switched paths with the plurality nodes using the backup status information; and

communicating with an adjacent node in order to establish a path reliability value for each path recorded in the backup status information using a reliability value from the adjacent node, in order to establish node realignment.

2. The method as claimed in claim 1, further comprising the node exchanging the path reliability value with the adjacent node for a path traversing the adjacent node to establish a cumulative path reliability value for the path.

3. The method as claimed in claim 2, further comprising comparing the cumulative path reliability value with a path reliability threshold to determine whether the path is reliable.

4. The method as claimed in claim 3, wherein the path reliability threshold is a function of a number of hops in the path.

5. The method as claimed in clam 3, wherein the comparison is based on the number of hops in the path and a number of adjacent nodes which do not have path recorded in their backup status information.

6. A node for use in a label switched network comprising a plurality of nodes, the node comprising:

a processor operable periodically to create a backup status record for the node;

a memory arranged to store the backup status record;

a network interface operable to receive path reliability values from an adjacent node;

the processor arranged to re-start the node on command and to restore the node to a state defined by the backup status record; and

the processor further arranged to calculate a path reliability value.

7. The node as claimed in claim 6, wherein the network interface is operable to receive a path reliability value for a path from the adjacent node, modify the received path reliability value dependent on an internally held path reliability value for the path, and pass the modified receive path reliability value to another adjacent node.

8. The node as claimed in claim 7, wherein the processor is arranged to modify the internally held path reliability value to establish a cumulative path reliability value for the path.

9. The node as claimed in claim 8, wherein the processor is arranged to compare the cumulative path reliability value with a path reliability threshold to determine whether the path is reliable.

10. The node as claimed in claim 9, wherein the processor is arranged to calculate the path reliability threshold as a function of a number of hops in the path.

11. A non-transitory machine-readable storage medium having computer code stored therein, which when executed by a set of one or more processors of a node in a label switched network comprising a plurality of nodes, causes the node to perform operations comprising:

periodically maintaining backup path status information for the node;

in response to restarting of the node, re-establishing label switched paths with the plurality of nodes using the backup status information; and

communicating with an adjacent node in order to establish a path reliability value for each path recorded in the backup status information using a reliability value from the adjacent node, in order to establish node realignment.