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IOS Upgradation Path

Hello Experts,

Can you please advice me on the Process (eg: ITIL) / Checklist to be done before & after the IOS Upgradation for a CISCO Router. For Eg: 7206 VXR PE Router as Service Provider Network.

1. Validation steps required before IOS Upgrade

2. Validation steps required after IOS Upgrade

3. Roll-back plan, if the IOS Upgrade fails

Note: Validation in-terms of Hardware as well as Software Level.

Thanks in Advance for your Answers.

Thanks & Regards,

Guru Prasad R


Re: IOS Upgradation Path

format flash:

copy tftp flash:

it will ask for tftp location. This is the place you put the IOS.

dir flash:

This will show you the contents of the flash:

then reload the router.

Once it is back up do:

sho ver

this will show you if the IOS upgrade was complete.

If you need to go back then make sure you copy flash: tftp

This will take all files on the flash and place it in your TFTP server.

Re: IOS Upgradation Path

Hi Guru,

Here you are what popped out of my mind right now:

Check that the new IOS supports the same features you required in the old one (use the feature navigator - most recommended to use the same feature set and Train).

Check the min DRAM/Flash.

Check the release notes of the new IOS for any serious caveats.

Test the IOS in your labs with the exact configuration.

Take benchmarks of your currently running router with the old IOS (CPU utilization, memory usage, interfaces, ...).

Prepare a checklist for all the router operations that you need to check (routing protocols, interfaces, ...).

Copy the new image on your in production router, and make sure that the old image is also there.

Validate the image on the new router using the verify command.

Issue a maintenance window for the upgrade with enough time to do the upgrade, test all the router operations and roll-back if required.

Make sure that you have a console access to the router (i'd recommend that you monitor the booting in order to notice any weird issue).

Change the router with the new boot statement, and make sure that the router has a secondary boot statement just in case.

Reload the router.

Monitor the boot sequence to spot any errors.

After the router boots up with the new IOS, check the already made checklist and benchmarks.

If initially there seems to be no problem, then you are done, and keep the router under monitoring for a couple of days.

If you faced any issues, then just edit the boot statement to use the old IOS and roll-back.

I hope that this helps.


Mohammed Mahmoud.

Re: IOS Upgradation Path

Dear Mohammed,

Thanks for your POST, Have rated.

I have come through a CISCO Link Yesterday night, its more useful for IOS Management on a HA Networking.

Take your own time upon reading the same. Refer Link below:

Hope I am Informative.

Best Regards,

Guru Prasad R

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