FAILOVER AND FAILBACK OF COMMUNICATION BETWEEN A ROUTER AND A NETWORK SWITCH

• US 20100142368A1
• Filed: 12/05/2008
• Published: 06/10/2010
• Est. Priority Date: 12/05/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Lim, Byung, Gunukula, Naveen, Puthenparambil, Jeslin, Nguyen, Son
• Granted Patent: US 8,094,569 B2
• Time in Patent Office: Days
• US Class Current: 370/217
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

A router is provided. The router includes a primary interface, a backup interface, a processor, and a memory. The primary interface and backup interface may be used to communicate with a network switch. The router may be configured to determine whether the primary interface is stable. The primary interface is stable when the primary interface may be used to exchange information with a network switch over a primary network segment. The router may be configured to activate the primary interface when the primary interface is determined to be stable. The router may also be configured to activate the backup interface when the primary interface is determined to be not stable. The backup interface may be activated for the exchange of information with the network switch.

Claims

1. A router system comprising:

a primary interface of a router, the primary interface being operable for communication over a primary network segment;

a backup interface of the router, the backup interface being operable for communication over a backup network segment;

a processor, the primary interface and the backup interface being coupled with the processor; and

a memory in communication with the processor, the memory including computer code executable with the processor, wherein the computer code is configured to;

determine whether the primary interface is stable, the primary interface being stable when the primary interface may be used to exchange information over the primary network segment;

communicate using the primary interface when the primary interface is determined to be stable; and

communicate using the backup interface when the primary interface is determined to be not stable.

2. The router system of claim 1, where the primary network segment includes a copper cable and the backup interface includes an optical fiber.

3. The router system of claim 1, where the computer code is also configured to:

monitor the primary interface after determining that the primary interface is not stable, where monitoring includes checking whether the primary interface is stable;

determine when the primary interface becomes stable; and

switch communication from the backup interface to the primary interface, such that the primary interface is used to communicate.

4. The router system of claim 1, where the computer code is configured to communicate with a network switch using the primary interface when the primary interface is determined to be stable, and communicate with the network switch using the backup interface when the primary interface is determined to be not stable.

5. The router system of claim 1, where the computer code is also configured to determine whether the backup interface is stable, the backup interface being stable when the backup interface may be used to exchange information over the backup network segment.

6. The router system of claim 1, where the computer code is also configured to move communication to another router when the primary interface and backup interface are not stable.

7. The router system of claim 1, where the primary interface and backup interface are connected to a multiplexor that is coupled with the processor, the processor being associated with an address device having a physical address.

8. A method comprising:

selecting a first router interface for communication, the selected first router interface being operable to communicate using a first network segment;

determining whether the selected first router interface is stable;

using the selected first router interface to communicate with the network switch when the selected first router interface is stable;

determining whether a second router interface is stable when the selected first router interface is not stable; and

moving communication to a second router interface when the second router interface is stable.

9. The method of claim 8, where determining whether the selected first router interface is stable includes counting a number of transitions of energy on the selected first router interface during a transition count window and comparing the number of transitions to a randomly selected transition threshold, the transition count window having a first randomly selected time duration.

10. The method of claim 9, where determining whether the selected first router interface is stable includes determining that the selected first router interface is stable when the number of transitions is less than the randomly selected transition threshold and the selected first router interface is active at an end of a hold count window having a second randomly selected time duration, the second randomly selected time duration being longer than the first randomly selected time duration.

11. The method of claim 8, further comprising monitoring the first router interface to determine when the first router interface is stable;

and moving communication back to the first router interface when the first router interface is stable.

12. The method of claim 8, further comprising switching communication to another router when the first router interface and second router interface are not stable.

13. The method of claim 8, further comprising using a multiplexor to communicate with the first router interface and second router interface, such that a processor may communicate with the first router interface and second router interface.

14. The method of claim 8, wherein the first router interface is coupled with a copper cable and the second router interface is coupled with an optical fiber.

15. A method, comprising:

selecting a first router interface for communication with a network switch, the selected first router interface being operable to communicate with the network switch using a first network segment;

counting a number of transitions on the selected first router interface, the number of transitions being counted during a transition count window having a first time duration;

determining whether the selected first router interface is stable based on the number of transitions; and

moving communication with the network switch to a second router interface when the selected first router interface is not stable, the second router interface being operable to communicate with the network switch using a second network segment.

16. The method of claim 15, where determining whether the selected first router interface is stable includes determining whether the selected first router interface is active at an end of a hold count window.

17. The method of claim 16, where the hold count window has a second time duration, the second time duration being longer than the first time duration of the transition count window.

18. The method of claim 16, wherein a time duration of the second transition count window and a time duration of the first transition count window are randomly selected.

19. The method of claim 15, further comprising:

determining whether the second router interface is stable; and

moving communication with the network switch to a second router when the first router interface and the second router interface are not stable.

20. The method of claim 16, where counting the number of transitions includes counting the number of transitions of energy detected on the first router interface.