METHOD AND NETWORK NODES FOR REPORTING AT LEAST ONE DROPPED-OUT CONNECTION PATH WITHIN A COMMUNICATION NETWORK

• US 20090154345A1
• Filed: 02/23/2009
• Published: 06/18/2009
• Est. Priority Date: 07/25/2003
• Status: Abandoned Application

• Current Assignee: Nokia Siemens Networks GmbH & Company KG (Nokia Corporation)
• Original Assignee: Nokia Siemens Networks GmbH & Company KG (Nokia Corporation)
• Inventors: Winkler, Christian, Schollmeier, Gero
• Application Number:
  US12/390,859
• Publication Number:
  US 20090154345A1
• Time in Patent Office: Days
• US Class Current: 370/228
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/026 Details of "hello" or keep-alive messages
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

A network node in the communication network is a target network node, connected by a first communication path with at least one first and one second network node, connected to each other by means of a further communication path. A routing table is held in each network node. The direct communication path from the first network node to the target network node is entered in the routing table of the first network node as the primary routing path and the path leading from the first network node to the second network node and then to the target network node is entered as the reserve routing path. An analogous entry is made in the routing table of the second network node. The relevant reserve routing path is only used on disruption of the primary routing path. A disruption in the primary communication path, provided between the first network node and the target network node is reported by the first network node, by means of a message sent to the second network node. This controls the second network node such that, on a drop-out of the primary connection path thereof to the target network node, a transmission of data packets to the target network node by means of the reverse routing path, leading from the second network node to the target network node via the first network node, is prevented.

Claims

1. A method for reporting a dropped-out connection path of a first network node to a second network node within a packet switching communication network, comprising:

providing a first routing table to the first node, the first routing table including a primary entry representing a primary routing path and an alternate entry representing an alternate routing path,

wherein the primary path is a connection path between the first node and the destination node, and

wherein the alternate path is a connection path between the first node and the destination node via the second node;

providing a second routing table to the second node, the second routing table including a primary entry representing a primary routing path and an alternate entry representing an alternate routing path,

wherein the primary path is a connection path between the second node and the destination node, and

wherein the alternate path is a connection path between the second node and the destination node via the first node;

detecting a first fault by the first node of the primary path of the first node;

reporting the first fault detected by the first node to the second node;

detecting a second fault by the second node of the primary path of the second node;

inhibiting a transfer of a data packet to the destination network node via the alternate path of the second node; and

reporting the second fault detected by the second node to the first node,

wherein the relevant alternate routing path entry is used if there is a fault on the primary routing path,

whereby a transfer back and forth between the first and second nodes of a data packet to be sent towards the destination network is inhibited, thereby reducing a load of the first and second nodes.

2. The method according to claim 1, wherein the first and/or second fault is reported via sending a message.

3. The method according to claim 2, wherein the message is sent substantially immediately after the detection of the respective fault.

4. The method according to claim 2, wherein the message is transferred cyclically on the primary connection path.

5. The method according to claim 1, wherein the transfer of the data packet is prevented.

6. The method according to claim 1, wherein the first and/or second fault is reported via a routing protocol.

7. The method according to claim 2, further comprising:

reporting the first fault to a neighboring node respective to the first node; and

informing the neighboring node after the end of the first fault.

8. The method according to claim 7, wherein the fault is reported to the neighboring node within a keep-alive message.

9. The method according to claim 7, wherein a node identifier of the first node is used to report the fault to the neighboring node.

10. The method according to claim 2, further comprising:

informing a neighboring node respective to the second node of the second fault; and

informing the neighboring node after the end of the second fault.

11. The method according to claim 10, wherein the fault is reported to the neighboring node within a keep-alive message.

12. The method according to claim 10, wherein a node identifier of first node is used to report the fault to the neighboring node.

13. A method for reporting a dropped-out connection path of a first network node to a second network node within a packet switching communication network, comprising:

providing a first routing table to the first node, the first routing table including a primary entry representing a primary routing path and an alternate entry representing an alternate routing path,

wherein the primary path is a connection path between the first node and the destination node, and

wherein the alternate path is a connection path between the first node and the destination node via the second node;

providing a second routing table to the second node, the second routing table including a primary entry representing a primary routing path and an alternate entry representing an alternate routing path,

wherein the primary path is a connection path between the second node and the destination node, and

wherein the alternate path is a connection path between the second node and the destination node via the first node;

periodically transferring a message from the first node to the second node while the first node has access to the destination network node via the respective primary path;

stopping the periodic transfer when a first fault is detected on the primary path of the first node;

detecting a second fault on the primary path of the second node; and

avoiding a transfer of a data packet to the destination node via the alternate routing path that leads from the second node to the first node.

14. The method according to claim 13, wherein the transfer of the data packet is prevented.

15. A first network node within a packet switching communication network having a first primary path that is a connection path between the first node and a destination node and a first alternate path that is a connection path between the first node and a second node, and the second node having a second primary path that is a connection path between the second node and the destination node and a second alternate path that is a connection path between the second node and the first node, the first node comprising:

a routing table including a primary entry representing the first primary path and an alternate entry representing the first alternate path;

a first fault indicator that indicates if the first primary path is available;

a second fault indicator that indicates if the second primary path is available to the second node; and

a receiver that receives a data packet to be transferred to the destination node;

wherein when the first and second fault indicators indicates the paths are unavailable, transfer of the data packet on the first paths is inhibited.

16. The node according to claim 15, wherein when the first fault indicator indicates that the first primary path is available, a message is periodically sent the second node to indicate that the path is available.

17. The node according to claim 16, wherein when the first fault indicator indicates that the first primary path is unavailable, the first node stops sending the periodic message.

18. The node according to claim 15,

wherein within a time period the first node receives a periodic message from the second node to indicate that the second primary path is available, in which the second fault indicator is set to indicate that the second primary path is available, and

wherein within the time period the first node does not receive the periodic message and the second fault indicator is set to indicate that the second primary path is unavailable.