Stateless redundancy in a network device

• US 20040083403A1
• Filed: 10/28/2002
• Published: 04/29/2004
• Est. Priority Date: 10/28/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Khosravi, Hormuzd M.
• Granted Patent: US 7,197,664 B2
• Time in Patent Office: Days
• US Class Current: 714/13
• CPC Class Codes: G06F 11/2025 using centralised failover control functionality
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component

Abstract

A method and apparatus to provide fault tolerance for a network device are described.

Claims

1. A method to provide fault tolerance, comprising:

identifying a first control element as a primary control element;

identifying a second control element as a secondary control element;

synchronizing information between said primary and secondary control elements;

detecting a failure condition in said primary control element; and

identifying said secondary element as said primary control element in case of said failure condition.

2. The method of claim 1, wherein said synchronizing comprises receiving said information from a forwarding element at both said primary and secondary control elements.

3. The method of claim 2, further comprising:

receiving control information from said primary and secondary control elements at said forwarding element; and

discarding said control information from said secondary control element.

4. The method of claim 2, further comprising:

receiving control information from said secondary control element at a blocking agent; and

discarding said control information from said secondary control element.

5. The method of claim 1, wherein said detecting comprises:

communicating status messages between said forwarding element and said primary control element on a periodic basis;

determining whether each status message is received within a predetermined interval; and

identifying said failure condition in accordance with said determination.

6. The method of claim 5, wherein said status messages are communicated in accordance with a Common Open Policy Service (COPS) Specification.

7. The method of claim 1, wherein said information may comprise data packets and forwarding element state information.

8. The method of claim 1, wherein said information is received in accordance with a Forwarding And Control Element Separation (ForCES) protocol.

9. An apparatus, comprising:

a plurality of forwarding elements;

a primary control element;

a secondary control element;

a backplane connected to said forwarding elements, said primary control element and said secondary control element, to communicate information between said elements; and

a fault tolerant management (FTM) module to synchronize information between said primary control element and said secondary control element, and to identify said secondary control element as said primary control element if said primary control element fails.

10. The apparatus of claim 9, wherein said FTM module further comprises a fault detection (FD) module to detect a failure condition for said primary control element.

11. The apparatus of claim 10, wherein said FD module communicates status messages in accordance with a Common Open Policy Service (COPS) Specification.

12. The apparatus of claim 9, wherein said information may comprise data packets and forwarding element state information.

13. The apparatus of claim 9, wherein said information may be synchronized by communicating said information in accordance with a Forwarding And Control Element Separation (ForCES) Protocol.

14. An article comprising:

a storage medium;

said storage medium including stored instructions that, when executed by a processor, result in providing fault tolerance by identifying a first control element as a primary control element, identifying a second control element as a secondary control element, synchronizing information between said primary and secondary control elements, detecting a failure condition in said primary control element, and identifying said secondary element as said primary control element in case of said failure condition

15. The article of claim 14, wherein the stored instructions, when executed by a processor, further result in said synchronizing by receiving said information from a forwarding element at both said primary and secondary control elements.

16. The article of claim 15, wherein the stored instructions, when executed by a processor, further result in receiving control information from said primary and secondary control elements at said forwarding element, and discarding said control information from said secondary control element.

17. The article of claim 15, wherein the stored instructions, when executed by a processor, further result in receiving control information from said secondary control element at a blocking agent, and discarding said control information from said secondary control element.

18. The article of claim 14, wherein the stored instructions, when executed by a processor, further result said detecting by communicating status messages between said forwarding element and said primary control element on a periodic basis, determining whether each status message is received within a predetermined interval, and identifying said failure condition in accordance with said determination.

19. A system, comprising:

a computing platform to provide fault tolerance;

said platform being further adapted to identifying a first control element as a primary control element, identifying a second control element as a secondary control element, synchronizing information between said primary and secondary control elements, detecting a failure condition in said primary control element, and identifying said secondary element as said primary control element in case of said failure condition.

20. The system of claim 19, wherein said platform is further adapted to perform said synchronizing by receiving said information from a forwarding element at both said primary and secondary control elements.

21. The system of claim 20, wherein said platform is further adapted to receiving control information from said primary and secondary control elements at said forwarding element, and discarding said control information from said secondary control element.

22. The system of claim 20, wherein said platform is further adapted to receiving control information from said secondary control element at a blocking agent, and discarding said control information from said secondary control element.

23. The system of claim 19, wherein said platform is further adapted to said detecting by communicating status messages between said forwarding element and said primary control element on a periodic basis, determining whether each status message is received within a predetermined interval, and identifying said failure condition in accordance with said determination.