Method and system for minimal disruption during software upgrade or reload of a network device

• US 7,814,481 B1
• Filed: 08/21/2003
• Issued: 10/12/2010
• Est. Priority Date: 08/21/2003
• Status: Active Grant

• Current Assignee: Cisco Systems, Inc.
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Vadhyar, Ratheesh Krishna, Welder, John Thomas, Uban, Thomas W., Rao, Sudhir
• Primary Examiner(s): RUTTEN, JAMES D
• Application Number:
  US10/646,453
• Time in Patent Office: 2,609 Days
• Field of Search: 717/168
• US Class Current: 717/176
• CPC Class Codes: G06F 15/177 Initialisation or configuration control processor initialisation G06F9/4405
• CPC Class Codes: G06F 8/65 Updates security arrangements therefor G06F21/57
• CPC Class Codes: G06F 9/445 Program loading or initiating bootstrapping G06F9/4401; security arrangements for program loading or initiating G06F21/57
• CPC Class Codes: H04L 41/082 the condition being updates or upgrades of network functionality
• CPC Class Codes: H04L 67/145 avoiding end of session, e.g. keep-alive, heartbeats, resumption message or wake-up for inactive or interrupted session

Abstract

A method and system for resetting a network device. Specifically, in one embodiment, a method is disclosed for upgrading and/or reloading software for a network device with minimal disruption. The method begins by separating operations associated with layer two of an International Standardization Organization Open Systems Interconnect (ISO/OSI) reference model from other layers in the ISO/OSI reference model in a network device. Then, the software operations in layer two of the network device are reset. The software operations are reset while maintaining continuity for a communication session between the network device and other network devices coupled together through a network. Thereafter, for minimal disruption, execution of the software operations is recovered at layer two before continuity of the communication session s terminated.

Claims

1. A method of resetting an electronic device comprising:

separating software operations associated with layer two of an International Standardization Organization Open Systems Interconnect (ISO/OSI) reference model from other layers in said ISO/OSI reference model, wherein said electronic device is configured to implement said software operations, and wherein a copy of said software operations is stored locally on said electronic device;

resetting said software operations in said layer two of said electronic device using said copy of said software operations, wherein a layer two functionality associated with said software operations is temporarily unavailable during said software reset;

maintaining continuity for a communication session between said electronic device and other electronic devices coupled together through a network during said software reset; and

recovering execution of said layer two functionality associated with said software operations before said continuity of said communication session is terminated.

2. The method of claim 1, further comprising:

separating a data plane and a control plane in said electronic device, wherein said data plane is associated with said layer two, and wherein said control plane is associated with layers above said layer two of said ISO/OSI reference model.

3. The method of claim 1, further comprising:

separating a data plane and a physical layer of said electronic device, wherein said data plane is associated with said layer two, and wherein said physical layer is associated with layer one of said ISO/OSI reference model; and

maintaining continuity of said communication session between said electronic device and said other electronic devices coupled together through said network at said layer one of said ISO/OSI reference model during said software reset.

4. The method of claim 1, wherein said copy of said software operations is stored at a first memory location of said electronic device, and wherein said method further comprises:

loading a bootstrap code to a second memory location of said electronic device, wherein said bootstrap code is loaded in response to a request to reset said electronic device, wherein said bootstrap code is configured to load said copy of said software operations from said first memory location to a predetermined location of said electronic device, and wherein said copy of said software operations replaces said software operations previously residing at said predetermined location.

5. The method of claim 4, further comprising:

executing said bootstrap code by moving a program counter of said electronic device to a first beginning instruction of said bootstrap code to overwrite said software operations at said predetermined location with said copy of said software operations; and

executing said copy of said software operations by moving said program counter to a second beginning instruction of said copy of said software operations.

6. The method of claim 1, further comprising:

performing a minimal reset of hardware components associated with said layer two such that interruptions to an operating system of said electronic device are minimized.

7. The method of claim 6, wherein at least one of said hardware components comprises a line card.

8. The method of claim 1, wherein said network comprises the Internet.

9. The method of claim 1, wherein said electronic device comprises a network device.

10. The method of claim 1, wherein said continuity of said communication session between said electronic device and said other electronic devices is maintained at ISO/OSI layers above said layer two during said software reset.

11. The method of claim 1, further comprising:

storing layer two information associated with usage of said software operations prior to resetting said software operations; and

restoring said layer two information associated with said usage of said software operations after recovering execution of said layer two functionality.

12. A method comprising:

initiating a communication between an electronic device and one or more devices in a network, wherein a data plane and a control plane in said electronic device are separated, wherein said data plane and said control plane are configured to control said communication between said electronic device and said one or more devices in said network, and wherein said data plane is associated with layer two of an International Standardization Organization Open Systems Interconnect (ISO/OSI) reference model;

loading a bootstrap code to said electronic device, wherein said bootstrap code is configured to load software operations for said electronic device;

loading said software operations in said data plane, wherein data plane functionality is temporarily disabled during said loading of said software operations;

maintaining continuity in said communication at layer one of said ISO/OSI reference model during said loading of said software operations, wherein said data plane is separated from said layer one of said electronic device;

maintaining continuity in said communication at layers above said layer two during said loading of said software operations; and

recovering execution of said data plane functionality before said continuity, in said communication is terminated at said control plane.

13. The method of claim 12, further comprising:

pre-loading new software implementing said software operations to a first memory location of said electronic device, wherein said bootstrap code is loaded to a second memory location of said electronic device, and wherein said bootstrap code loads said new software to a predetermined location storing existing software implementing said software operations.

14. The method of claim 13, further comprising:

moving a program counter of said electronic device to a first beginning instruction of said bootstrap code for executing said bootstrap code to overwrite said existing software at said predetermined location with said new software; and

executing said new software by moving said program counter to a second beginning instruction of said new software to initialize said new software.

15. The method of claim 13, further comprising:

upgrading said software operations that are implemented within said new software.

16. The method of claim 13, further comprising:

reloading said software operations that are implemented within said new software.

17. The method of claim 12, further comprising:

performing a minimal reset of hardware components associated with said data plane such that interruptions to an operating system of said electronic device are minimized.

18. The method of claim 17, further comprising:

resuming operations of said hardware components.

19. The method of claim 12, wherein said electronic device comprises a network device.

20. The method of claim 12, wherein said bootstrap code is loaded in response to a request to reset said electronic device, and wherein said software operations are preloaded on said electronic device prior to receiving said request to reset said electronic device.

21. The method of claim 12, wherein a copy of said software operations is stored on said electronic device, and wherein said bootstrap code loads said copy of said software operations from a first memory location of said electronic device to a second memory location of said electronic device.

22. A system comprising:

means for separating software operations associated with layer two of an International Standardization Organization Open Systems Interconnect (ISO/OSI) reference model from other layers in said ISO/OSI reference model, wherein an electronic device is configured to implement said software operations;

means for storing layer two information associated with usage of said software operations;

means for loading said software operations in said layer two of said electronic device, wherein said layer two is temporarily disabled during said loading of said software operations;

means for maintaining continuity for a communication session between said electronic device and other electronic devices coupled together through a network while said layer two is temporarily disabled;

means for restoring said layer two information associated with said usage of said software operations; and

means for recovering execution of said software operations at said layer two before said continuity of said communication session is terminated.

23. The system of claim 22, wherein said means for separating software operations further comprises:

means for separating a data plane and a control plane in said electronic device, said data plane being associated with said layer two, and said control plane being associated with layers above said layer two of said ISO/OSI reference model.

24. The system of claim 22, wherein said means for maintaining continuity further comprises:

means for maintaining continuity at layer one of said ISO/OSI reference model; and

means for maintaining continuity at layers above said second layer of said ISO/OSI reference model.

25. The system of claim 22, wherein said means for loading said software operations further comprises:

means for pre-loading new software implementing said software operations to a first memory location of said electronic device; and

means for loading a bootstrap code to a second memory location of said electronic device, wherein said bootstrap code is configured to load said new software to a predetermined location, and wherein said predetermined location is configured to store existing software implementing said software operations.

26. The system of claim 25, wherein said means for recovering execution further comprises:

means for executing said bootstrap code by moving a program counter of said electronic device to a first beginning instruction of said bootstrap code to overwrite said existing software at said predetermined location with said new software; and

means for executing said new software by moving said program counter to a second beginning instruction of said new software to initialize said new software.

27. The system of claim 22, wherein said network comprises the Internet.

28. The system of claim 22, wherein said electronic device comprises a network device.

29. The system of claim 22, wherein said software operations loaded to said electronic device comprise a copy of said software operations, and wherein said copy of said software operations resets said electronic device.

30. The system of claim 22, wherein said software operations loaded to said electronic device comprise a new version of said software operations, and wherein said new version of said software operations upgrades said electronic device.

31. A computer-readable medium having stored thereon computer executable instructions that, if executed by a system, cause said system to perform operations comprising:

separating software operations associated with layer two of an International Standardization Organization Open Systems Interconnect (ISO/OSI) reference model from other layers in said ISO/OSI reference model, wherein an electronic device is configured to implement said software operations;

loading said software operations in said layer two of said electronic device, wherein a layer two functionality associated with said software operations is temporarily unavailable during said loading of said software operations;

maintaining continuity for a communication session between said electronic device and other electronic devices coupled together through a network while said layer two functionality is unavailable; and

recovering execution of said software operations at said layer two before said continuity of said communication session is terminated.

32. The computer-readable medium of claim 31, wherein said operations further comprise:

separating a data plane and a control plane in said electronic device, wherein said data plane is associated with said layer two, and wherein said control plane is associated with layers above said layer two of said ISO/OSI reference model.

33. The computer-readable medium of claim 31, wherein said operations further comprise:

maintaining continuity at layer one of said ISO/OSI reference model; and

maintaining continuity at layers above said second layer of said ISO/OSI reference model.

34. The computer-readable medium of claim 31, wherein said operations further comprise:

pre-loading new software implementing said software operations to a first memory location of said electronic device; and

loading a bootstrap code to a second memory location of said electronic device, wherein said bootstrap code is configured to load said new software to a predetermined location, and wherein said predetermined location is configured to store stung existing software implementing said software operations.

35. The computer-readable medium of claim 34, wherein said operations further comprise:

executing said bootstrap code by moving a program counter of said electronic device to a first beginning instruction of said bootstrap code to overwrite said existing software at said predetermined location with said new software; and

executing said new software by moving said program counter to a second beginning instruction of said new software to initialize said new software.

36. The computer-readable medium of claim 31, wherein said operations further comprise:

performing a minimal reset of hardware components associated with said layer two such that interruptions to an operating system of said electronic device are minimized.

37. The computer-readable medium of claim 36, wherein at least one of said hardware components comprises a line card.

38. The computer-readable medium of claim 31, wherein said network comprises the Internet.

39. The computer-readable medium of claim 31, wherein said electronic device comprises a network device.

40. The computer-readable medium of claim 31, wherein said operations further comprise:

storing layer two information associated with usage of said software operations prior to loading said software operations; and

restoring said layer two information associated with said usage of said software operations after recovering execution of said layer two functionality.

41. The computer-readable medium of claim 31, wherein said software operations are loaded as part of loading said electronic device.

42. A system for resetting an electronic device comprising:

means for separating software operations associated with layer two of an International Standardization Organization Open Systems Interconnect (ISO/OSI) reference model from other layers in said ISO/OSI reference model, said electronic device implementing said software operations;

means for resetting said software operations in said layer two of said electronic device, wherein said layer two is temporarily disabled during said resetting of said software operations;

means for maintaining continuity for a communication session between said electronic device and other electronic devices coupled together through a network;

means for recovering execution of said software operations at said layer two before said continuity of said communication session is terminated; and

means for performing a minimal reset of hardware components associated with said layer two such that interruptions to an operating system of said electronic device are minimized, wherein at least one of said hardware components comprises a line card.

43. The system of claim 42, wherein said line card comprises an Ethernet card, wherein an operation of said Ethernet card is interrupted, and wherein said continuity for said communication session between said electronic device and said other electronic devices is maintained while said operation of said Ethernet card is interrupted.