Router software upgrade employing redundant processors

• US 7,610,405 B1
• Filed: 04/16/2004
• Issued: 10/27/2009
• Est. Priority Date: 02/24/2000
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Kon, Ronnie, Moberg, Kenneth
• Primary Examiner(s): BOUTAH, ALINA A
• Application Number:
  US10/825,850
• Time in Patent Office: 2,020 Days
• Field of Search: 709/242, 370/216, 370219-221, 370/225, 714/11, 714/13, 700/82
• US Class Current: 709/242
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/563 Software download or update
• CPC Class Codes: H04L 45/58 Association of routers

Abstract

Systems and methods for replacing software controlling active routers while minimizing impact on network operation are provided by virtue of one embodiment of the present invention. The software replacement process takes advantage of packet processor redundancy. An active packet switching device to be reprogrammed is de-activated and a redundant packet switching device takes over. The no longer active packet switching device is reprogrammed before being reactivated.

Claims

1. A computer-implemented method for reprogramming an active packet switching router without interfering with packet flow, said method comprising:

receiving a software upgrade message at a currently active packet switching device (A);

halting receipt of new packets at said packet switching device (A) upon receipt of said software upgrade message;

transferring protocol state information, including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to a currently inactive packet switching device (B);

reprogramming said packet switching device (B);

sending a message requesting activation from said packet switching device (A) to said packet switching device (B);

de-activating said packet switching device (A) and activating said reprogrammed packet switching device (B) to handle packet flow previously handled by said packet switching device (A), including beginning receipt of new packets at said packet switching device (B);

reprogramming said packet switching device (A), including retrieving new packet processing software from a remote location; and

thereafter

de-activating said packet switching device (B) and re-activating said packet switching device (A).

2. The method of claim 1 wherein reprogramming said packet switching device (B) comprises retrieving new packet processing software from a remote location.

3. The method of claim 1 wherein said protocol state information comprises register values.

4. The method of claim 1 further comprising:

operating said packet switching device (A) as a back-up after de-activating said packet switching device (A).

5. A computer-implemented method for reprogramming an active packet switching router without interfering with packet flow, said method comprising:

receiving a software upgrade message at a currently active packet switching device (A);

halting receipt of new packets at said packet switching device (A) upon receipt of said software upgrade message;

transferring protocol state information comprising register values including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to a currently inactive packet switching device (B);

sending a message requesting activation from said packet switching device (A) to said packet switching device (B);

de-activating said packet switching device (A) and activating said reprogrammed packet switching device (B) to handle packet flow previously handled by said packet switching device (A), including beginning receipt of new packets at said packet switching device (B);

reprogramming said packet switching device (A), including retrieving new packet processing software from a remote location; and

thereafter

de-activating said packet switching device (B) and re-activating said packet switching device (A).

6. The method of claim 5 further comprising:

reprogramming said packet switching device (B) prior to activating said packet switching device (B) including retrieving new packet processing software from a remote location.

7. The method of claim 5 further comprising:

operating said packet switching device (A) as a back-up after de-activating said packet switching device (A).

8. A computer-readable storage medium encoded with a computer program that reprograms an active packet switching router without interfering with packet flow, said computer program comprising:

code that receives a software upgrade message at a currently active packet switching device (A);

code that halts receipt of new packets at said packet switching device (A) upon receipt of said software upgrade message;

code that transfers protocol state information, including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to a currently inactive packet switching device (B);

code that sends a message requesting activation from said packet switching device (A) to said packet switching device (B);

code that reprograms said packet switching device (B) before said packet switching device (B) is activated;

code that de-activates said packet switching device (A) and activates said packet switching device (B) to handle packet flow previously handled by said packet switching device (A);

code that reprograms said packet switching device (A) after de-activation, including code that retrieves new packet processing software from a remote location; and

code that de-activates said packet switching device (B) and re-activates said packet switching device (A) after reprogramming.

9. The computer-readable storage medium of claim 8 wherein said code that reprograms said packet switching device (B) comprises code that retrieves new packet processing software from a remote location.

10. The computer-readable storage medium of claim 8 wherein said protocol state information comprises register values.

11. The computer-readable storage medium of claim 8 further comprising:

code that operates said packet switching device (A) as a back-up after said packet switching device (A) is de-activated.

12. A computer-readable storage medium encoded with a computer program that reprograms an active packet switching router without interfering with packet flow, said computer program comprising:

code that receives a software upgrade message at a currently active packet switching device (A);

code that halts receipt of new packets at said packet switching device (A) upon receipt of said software upgrade message;

code that transfers protocol state information comprising register values including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to a currently inactive packet switching device (B);

code that sends a message requesting activation from said packet switching device (A) to said packet switching device (B);

code that de-activates said packet switching device (A) and activates said packet switching device (B) to handle packet flow previously handled by said packet switching device (A);

code that reprograms said packet switching device (A) after de-activation, including code that retrieves new packet processing software from a remote location; and

code that de-activates said packet switching device (B) and re-activates said packet switching device (A) after reprogramming.

13. The computer-readable storage medium of claim 12 further comprising:

code that reprograms said packet switching device (B) before said packet switching device (B) is activated and further comprising code that retrieves new packet processing software from a remote location.

14. The computer-readable storage medium of claim 12 further comprising:

code that operates said packet switching device (A) as a back-up after said packet switching device (A) is de-activated.

15. A packet switching system comprising:

a currently active packet switching device (A);

a packet switching device (B); and

a memory system storing;

code that receives a software upgrade message at said packet switching device (A);

code that halts receipt of new packets at said packet switching device (A) upon receipt of said software upgrade message;

code that transfers protocol state information, including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to said packet switching device (B);

code that sends a message requesting activation from said packet switching device (A) to said packet switching device (B);

code that reprograms said packet switching device (B) before said packet switching device (B) is activated;

code that de-activates said packet switching device (A) and activates said packet switching device (B) to handle packet flow previously handled by said packet switching device (A);

code that reprograms said packet switching device (A) after de-activation, including code that retrieves new packet processing software from a remote location; and

code that de-activates said packet switching device (B) and re-activates said packet switching device (A) after reprogramming.

16. The system of claim 15 wherein said code that reprograms said packet switching device (B) comprises code that retrieves new packet processing software from a remote location.

17. The system of claim 15 wherein said protocol state information comprises register values.

18. The system of claim 15 further comprising:

code that operates said packet switching device (A) as a back-up after said packet switching device (A) is de-activated.

19. A packet switching system comprising:

a currently active packet switching device (A);

a packet switching device (B); and

a memory system storing;

code that receives a software upgrade message at said packet switching device (A);

code that halts receipt of new packets at said packet switching device (A) upon receipt of said software upgrade message;

code that transfers protocol state information comprising register values including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to said packet switching device (B);

code that sends a message requesting activation from said packet switching device (A) to said packet switching device (B);

code that de-activates said packet switching device (A) and activates said packet switching device (B) to handle packet flow previously handled by said packet switching device (A);

code that reprograms said packet switching device (A) after de-activation, including code that retrieves new packet processing software from a remote location; and

code that de-activates said packet switching device (B) and re-activates said packet switching device (A) after reprogramming.

20. The system of claim 19 further comprising:

code that reprograms said packet switching device (B) before said packet switching device (B) is activated and further comprising code that retrieves new packet processing software from a remote location.

21. The system of claim 19 further comprising:

code that operates said packet switching device (A) as a back-up after said packet switching device (A) is de-activated.

22. A packet switching system comprising:

a currently active packet switching device (A);

a currently inactive packet switching device (B); and

a memory system storing;

code that receives a failover message at said currently active packet switching device (A);

code that then transfers protocol state information, including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to said packet switching device (B);

code that reprograms said packet switching device (B) before said packet switching device (B) is activated;

code that de-activates said packet switching device (A), including code that sends a message requesting activation from said packet switching device (A) to said packet switching device (B) and code that halts receipt of new packets at said packet switching device (A) upon receipt of said failover message, and that activates said packet switching device (B), including code that begins receipt of new packets at said packet switching device (B);

code that reprograms said packet switching device (A) after said packet switching device (A) is de-activated, including code that retrieves new packet processing software from a remote location; and

code that reprograms said packet switching device (B) before said packet switching device (B) is activated.

23. The system of claim 22 wherein said code that reprograms said packet switching device (B) comprises code that retrieves new packet processing software from a remote location.

24. The system of claim 22 wherein said protocol state information comprises register values.

25. The system of claim 22 further comprising:

code that operates said packet switching device (A) as a back-up after said packet switching device (A) is de-activated.

26. A packet switching system comprising:

a currently active packet switching device (A);

a packet switching device (B); and

a memory system storing;

code that receives a software upgrade message at said packet switching device (A);

code that halts receipt of new packets at said packet switching device (A) upon receipt of said software upgrade message;

code that transfers protocol state information comprising register values including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to said packet switching device (B);

code that sends a message requesting activation from said packet switching device (A) to said packet switching device (B);

code that de-activates said packet switching device (A) and activates said packet switching device (B) to handle packet flow previously handled by said packet switching device (A);

code that reprograms said packet switching device (A) after de-activation, including code that retrieves new packet processing software from a remote location;

code that de-activates said packet switching device (B) and re-activates said packet switching device (A) after reprogramming; and

code that reprograms said packet switching device (B) before said packet switching device (B) is activated.

27. The system of claim 26 further comprising

code that reprograms said packet switching device (B) before said packet switching device (B) is activated and further comprising code that retrieves new packet processing software from a remote location.

28. The system of claim 26 further comprising:

code that operates said packet switching device (A) as a back-up after said packet switching device (A) is de-activated.

29. A packet switching router having a packet switching devices, said router comprising:

means for receiving a failover message at a currently active packet switching device (A);

means for then transferring protocol state information, including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to a currently inactive packet switching device (B);

means for sending a message requesting activation from said packet switching device (A) to said packet switching device (B);

means for halting receipt of new packets at said packet switching device (A) upon receipt of said failover message;

means for de-activating said packet switching device (A) and activating said packet switching device (B), including beginning receipt of new packets at said packet switching device (B); and

means for reprogramming said packet switching device (A) after de-activating said packet switching device (A), including retrieving new packet processing software from a remote location.

30. The router of claim 29 further comprising:

means for reprogramming said packet switching device (B) prior to activating said packet switching device (B).

31. The router of claim 30 wherein reprogramming comprises retrieving new packet processing software from a remote location.

32. The router of claim 29 further comprising:

means for operating said packet switching device (A) as a back-up after de-activating said packet switching device (A).

33. The method of claim 29 wherein said protocol state information comprises register values.

34. A packet switching router with a plurality of packet switching devices, said router comprising:

means for receiving a software upgrade message at a currently active packet switching device (A);

means for halting receipt of new packets at said packet switching device (A) upon receipt of said software upgrade message;

means for transferring protocol state information, including routing tables, negotiated state information, authorization status and learned routing state information, from said packet switching device (A) to a currently inactive packet switching device (B);

means for sending a message requesting activation from said packet switching device (A) to said packet switching device (B);

means for de-activating said packet switching device (A) and activating said packet switching device (B) to handle packet flow previously handled by said packet switching device (A), including beginning receipt of new packets at said packet switching device (B);

means for thereafter reprogramming said packet switching device (A), including retrieving new packet processing software from a remote location; and

means for thereafter de-activating said packet switching device (B) and re-activating said packet switching device (A).

35. The router of claim 34 further comprising:

means for reprogramming said packet switching device (B) prior to activating said packet switching device (B).

36. The router of claim 35 wherein reprogramming comprises retrieving new packet processing software from a remote location.

37. The router of claim 34 further comprising:

means for operating said packet switching device (A) as a back-up after de-activating said packet switching device (A).

38. The method of claim 34 wherein said protocol state information comprises register values.