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Switch IOS upgrade

networker101
Level 1
Level 1

Hi,

I am doing a project of upgrading Cisco IOS access switches for my company, I will have to do these all remotly which are placed all over Europe & UK.

I am in the process of writing a project plan and a bit stuck at the risks section.

Can you someone explain to me what happens if an upgrade fails? what are the main risks involved of upgrading and what will the actions be?

Any recomendations on how best to tackle this project? software, best practices etc etc..

Thanks for your help

2 Replies 2

IAN WHITMORE
Level 4
Level 4

OK here's a few.

If remote upgrade fails you could lose connectivity to your switch which you can only revoer on-site cos you might be in rommon mode might need to do a serial transfer to update.

If you choose the wrong IOS - bad idea. But the switch wii usually complain and not let you.

If you get a power cut during the update process it could render the switch useless (unlikely but you never know).

If you don't have enough flash free for the IOS you are uploading the switch will complain anyway. Workaround - delete the current IOS and upload the new. Of course if you delete the current IOS and reboot - you have no flash image to load - back to onsite serial transfer to recover from that.

The new IOS might change some of the default option i.e. something that might be automatically turned off in X might be on in Y. That could change the config (unlikely but depends if you are upgrading major versions or just releases).

Make sure, if you use "boot system" commands that you add the new IOS or change the exisiting (it's better to add to begin with because if one fais it will move on tto the next one). Of course if you have enough flash for various images, you need to make sure they are in the right order.

You could of course use this to your advantage and you'll get to travel all over europe (or get sacked ).

Regards,

Ian

Hi,

I would suggest you below things as per best practices...

1. Take backup of all switches for which you are going to IOS upgrade.
2. Have onsite contact person details in hand, if possible please have a onsite person physically.
3. If there is no any redundancy to reach the switch then I must recommend onsite person with console connect to the switch.
4. If you have redundnacy to reach the switch then have a console connection and standby make sure that onsite person available at any time.
5. Make sure communication between Switch and TFTP server.
6. If you have enough space in flash then dont remove the existing IOS, upload new IOS and give boot flash: command to boot with new IOS.


Please follow the below link for IOS upgrade in different switches.

IOS upgrade in L2 2950 & 2955 switches:
http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_example09186a0080169627.shtml

IOS upgrade in L3 Catalyst switches:
http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801347e2.shtml

IOS upgrade in Catalyst 3750 Stack switches:
http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00804799d7.shtml


Hope this will help you...

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Regards,
Naidu.

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