Router image support device

• US 6,438,606 B1
• Filed: 12/23/1998
• Issued: 08/20/2002
• Est. Priority Date: 12/23/1998
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Ward, Paul
• Primary Examiner(s): Rinehart, Mark H.
• Assistant Examiner(s): Vu, Thong H
• Application Number:
  US09/220,870
• Time in Patent Office: 1,336 Days
• Field of Search: 709/221, 709/230, 709/250, 709/223, 709/224, 709/220, 709/232, 709/228, 709/238, 709/226, 709/241, 713/1, 713/201, 713/2, 717/11, 717/4, 710/1, 714/25, 712/28, 707/1, 707/204, 707/10, 358/438
• US Class Current: 709/238
• CPC Class Codes: G06F 11/1433 during software upgrading
• CPC Class Codes: G06F 8/656 while running
• 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 45/243 using M+N parallel active paths
• CPC Class Codes: H04L 45/563 Software download or update
• CPC Class Codes: H04L 67/34 involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

A multi-network system is provided with a facility for storing an old or superseded router image without the need for increasing router memory. A local storage device is coupled, directly or indirectly, to a router. Before a new image is downloaded to the router, the old or superseded image is first stored in the support device. If the new image is defective or undesirable, the old image can be recovered, even if the wide area link is unopenable, by reloading the old image from the local storage device.

Claims

1. A method for restoring a router image for use in a multi-network computing system including a router which is coupled to both a local area network (LAN) and at least a first remote site, over a wide area network (WAN) link, said router having a memory for storing router images, said router images providing router LAW or operating systems for controlling the functioning of said routed, the method comprising:

coupling at least a first support device to said LAN without coupling said first support device to said remote site, said first support device having a memory;

downloading a first router image from said remote site, over said WAN link to said router memory and simultaneously transmitting a copy of said fist router image over said LAN to said first support device;

storing, in said memory of said first support device, said copy of said first router image;

erasing said first router image from said router memory;

downloading a second router image from said remote site, over said WAN link to said router memory and simultaneously transmitting a copy of said second router image over Ed LAN to said first support device; and

transmitting said copy of said first router image from said support device to said router, for storing in said memory of said router.

2. A method, as claimed in claim 1, wherein said first support device comprises a second router.

3. A method, as claimed in claim 2 wherein said coupling of said second router to said LAN is provided in the absence of coupling said router to a remote site.

4. A method, as claimed in claim 1, wherein said copy of said first router image is stored in said memory of said first support device following transmitting said copy of said first router image from said router, over said LAN, to said first support device.

5. A method, as claimed in claim 4 wherein said transmitting of said copy of said first router image from said router is performed substantially simultaneously with downloading of said first router image to said router from said remote site.

6. A method, as claimed in claim 1 further comprising storing a second router image, different from said first router image, into said router prior to said step of trans said copy of said first router image from said support device to said router.

7. A method, as claimed in claim 6 further comprising storing said second router image in said support device, without erasing said first router image from said support device.

8. A method as claimed in claim 7 wherein said step of storing said second router image in said support device is performed substantially simultaneously with said step of storing said second router image into said router.

9. A method as claimed in claim 7 further comprising storing a third router image in said support device while erasing at least a portion of said second router image from said support device if said first router image has been copied from said support device to said router.

10. A method as claimed in claim 7 further comprising storing a third router image in said support device while erasing at least a portion of said first router image from said support device if said first router image has not been copied from said support device to said router.

11. A method, as claimed in claim 7, further comprising prompting for user input to select between erasure of said first router image and said second router image before storing a third router image in said support device.

12. A method, as claimed in claim 6 further comprising said second router image from said router prior to said step of transmitting said copy of said first router image from said support device to said router.

13. A method as claimed in claim 12 further comprising storing said second router image in said support device after said step of storing said second router image in said router and before said step of erasing said second router image from said router.

14. A method for restoring a router image for use in a multi-network computing system including a first router which is coupled to both a local area network (IAN) and at least a first remote site, over a wide area network (WAN) link, said first router having a flash memory for storing router images, said router images providing router operating systems for controlling the functioning of said fast router, the method comprising:

coupling a second router to said LAN, without coupling said second router over a WAN, said second router having sufficient memory to store at least two images;

downloading a first image from said remote site, over said WAN link to said first router flash memory and simultaneously transmitting said first image over said LAN to said second router for storage in said memory of said second router,

erasing said first image from said flash memory of said first router,

downloading a second image from said remote site, over said WAN link to said first router flash memory and simultaneously transmitting said second image over said LAN to said second router for storage in said memory of said second router without erasing said first image from said memory of said second router, wherein said second image in said first router renders said first router incapable of maintaining said WAN link;

erasing said second image from said flash memory of said first router, and

transmitting said first image from said second router, over said LAN, to said fist router, for storing in said flash memory of said first router.

15. Apparatus for restoring a router image for use in a multinetwork computing system including a router which is coupled to both a local area network (LAN) and at least a first remote site, over a wide area network (WAN) link, said router having a memory for storing router images, said router images providing router operating systems for controlling the functioning of said routers, the apparatus comprising:

a first support device, coupled to said router, said first support device having a memory;

means for automatically storing, in said memory of said first support device, a copy of a first router image as said first router image is being stored in said router;

means for automatically storing, in said memory of said first support device, a copy of a second router image as said second router image is being stored in said router,

means for erasing said first and said second router images from said memory of said router; and

means for transmitting said copy of said first router image from said support device to said router, for storing in said memory of said router.

16. Apparatus, as claimed in claim 15, wherein said first support device is coupled to said router by said LAN.

17. Apparatus, as claimed in claim 16, wherein said means for transmitting said copy includes said LAN.

18. Apparatus, as claimed in claim 15, wherein said first support device comprises a second router.

19. Apparatus, as claimed in claim 15, wherein said means for automatically storing includes means for transmitting said copy of said first image from said router, over said LAN to said first support device.

20. Apparatus, as claimed in claim 15, wherein said means for automatically storing said second router image in said support device, without erasing said first router image from said support device.

21. Apparatus as claimed in claim 15 further comprising means for automatically selecting whether to erase said first router image or said second router image from said first support device before storing a third router image in said support device.