FUTILE NEIGHBOR STATE LOOP PREVENTION IN HIGH AVAILABILITY NETWORKS

• US 20090316570A1
• Filed: 06/19/2008
• Published: 12/24/2009
• Est. Priority Date: 06/19/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bell, Jon A.
• Granted Patent: US 7,869,347 B2
• Time in Patent Office: Days
• US Class Current: 370/218
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

A method for detecting and managing a futile neighbor state loop during link state routing is disclosed. The method can include reading a threshold parameter for link state routing, wherein the threshold parameter indicates a number of routing attempts, and performing link state routing to a node via a primary interface. The method can further include detecting a futile neighbor state loop during link state routing to the node via the primary interface by detecting a number of routing attempts that has reached the threshold parameter and detecting an available backup interface to the node. The method can further include suspending the primary interface to the node and switching routing to the backup interface.

Claims

1. A method for detecting and managing a futile neighbor state loop during link state routing, comprising:

reading a threshold parameter for link state routing, wherein the threshold parameter indicates a number of routing attempts;

performing link state routing to a node via a primary interface;

detecting a futile neighbor state loop during link state routing to the node via the primary interface by detecting a number of routing attempts that has reached the threshold parameter;

detecting an available backup interface to the node;

suspending the primary interface to the node; and

switching routing to the backup interface.

2. The method of claim 1, wherein the threshold parameter further indicates a pattern of link states.

3. The method of claim 2, wherein the first step of detecting further comprises:

detecting a futile neighbor state loop during link state routing to the node via the primary interface by detecting a number of routing attempts that has reached the threshold parameter and by detecting a pattern of link states.

4. The method of claim 3, wherein the first step of detecting further comprises:

displaying a message indicating that a futile neighbor state loop has been detected in the primary interface to the node.

5. The method of claim 4, wherein the second step of detecting further comprises:

displaying a message indicating that an available backup interface to the node has been detected.

6. A computer program product comprising a computer usable medium embodying computer usable program code for detecting and managing a futile neighbor state loop during link state routing, the computer program product comprising:

computer usable program code for reading a threshold parameter for link state routing, wherein the threshold parameter indicates a number of routing attempts;

computer usable program code for performing link state routing to a node via a primary interface;

computer usable program code for detecting a futile neighbor state loop during link state routing to the node via the primary interface by detecting a number of routing attempts that has reached the threshold parameter;

computer usable program code for detecting an available backup interface to the node;

computer usable program code for suspending the primary interface to the node; and

computer usable program code for switching routing to the backup interface.

7. The computer program product of claim 6, wherein the threshold parameter further indicates a pattern of link states.

8. The computer program product of claim 7, wherein the first computer usable program code for detecting further comprises:

computer usable program code for detecting a futile neighbor state loop during link state routing to the node via the primary interface by detecting a number of routing attempts that has reached the threshold parameter and by detecting a pattern of link states.

9. The computer program product of claim 8, wherein the first computer usable program code for detecting further comprises:

computer usable program code for displaying a message indicating that a futile neighbor state loop has been detected in the primary interface to the node.

10. The computer program product of claim 9, wherein the second computer usable program code for detecting further comprises:

computer usable program code for displaying a message indicating that an available backup interface to the node has been detected.

11. A method for detecting and managing a futile neighbor state loop during adjacency formation, comprising:

reading a threshold parameter for adjacency formation, wherein the threshold parameter indicates a pattern of link states;

performing adjacency formation with a node via a primary interface;

detecting a futile neighbor state loop during adjacency formation with the node via the primary interface by detecting the pattern of link states in the threshold parameter;

detecting an available backup interface to the node;

suspending the primary interface to the node; and

switching routing to the backup interface.

12. The method of claim 11, wherein the threshold parameter further indicates a number of routing attempts.

13. The method of claim 12, wherein the first step of detecting further comprises:

detecting a futile neighbor state loop during adjacency formation to the node via the primary interface by detecting the pattern of link states in the threshold parameter and a number of routing attempts that has reached the threshold parameter.

14. The method of claim 13, wherein the first step of detecting further comprises:

displaying a message indicating that a futile neighbor state loop has been detected in the primary interface to the node.

15. The method of claim 14, wherein the second step of detecting further comprises:

displaying a message indicating that an available backup interface to the node has been detected.