Couple questions about updating Switches

[mheddy439]

I have about 20 switches that need to have firmware updates, 

What is the best way to do it? TFTP? USB?

Was thinking of putting the file on USB, uploading it that way than loading it that way.

But everything I read says I need to reload the switch, is there a way I can do it without having to reload and losing the config that is currently there?

Thank you.

[balaji.bandi]

What is the best way to do it? TFTP? USB?
Was thinking of putting the file on USB, uploading it that way than loading it that way.

 

Depends on access, if the Access have Physical then use USB, if remote then use TFTP

But everything I read says I need to reload the switch, is there a way I can do it without having to reload and losing the config that is currently there?

You will not loose config by upgrading the IOS code, but if any un supported features may give you error.

After upgrade reload required for the new IOS to take effective

Note : make sure you read the release notes, any caveats.

[Joseph W. Doherty]

"Depends on access, if the Access have Physical then use USB, if remote then use TFTP"

If devices are "remote" with usual WAN latency, FTP generally will download images much faster.

[balaji.bandi]

Maybe not given enough clarity myself on TFTP, TFTP using Local devices, not far end I mean. (Hope that makes sense, rather I create a confusion)

yes if it is far end agreed different mode of transfer is preferred.

[David Ruess]

Hello,

That should be fine. You shouldn't lose the config if you're just updating the image. The only thing that will change is the switch version. Do you have a switch you can practice on?

Side note. If you want little disruption you need to make sure both the current image and the new image you load onto the switch can fit in memory. If not you will have to add more memory or remove the old image to put the new one on.

-David

[Joseph W. Doherty]

"Side note. If you want little disruption you need to make sure both the current image and the new image you load onto the switch can fit in memory. If not you will have to add more memory or remove the old image to put the new one on."

An additional side note, some devices can boot from USB, and even if not, USB can be a convenient place to store both old and new IOS images.

[Joseph W. Doherty]

"But everything I read says I need to reload the switch, is there a way I can do it without having to reload and losing the config that is currently there?"

As the other posters have noted, you shouldn't lose your config, although if might "change" with a newer IOS.  I.e. after booting a new IOS if you save the running config, the newly saved startup might not exactly match the prior (to update) startup.  Generally, this isn't a problem unless you're jumping across many IOS versions.  However, it can be a problem if you need to downgrade to what you had.  I.e. besides saving a copy of the IOS you're replacing, also save a copy of the startup config it was using.

As to not needing to "reload", generally that's always required on "small" switches.  Some of the "big" switches sometimes support some form of "in-service upgrade".

[Richard Burts]

Joseph makes a very good point that for most Cisco switches the upgrade process is in 2 phases. First you load the file(s) for the new version. Then you reload the switch to make the conversion from old version to new version. He is correct that for some of the newest (and biggest?) there is an in service option that will implement the new features without requiring a complete reboot of the entire switch.

To state an obvious point about whether you might lose your configuration when you perform an upgrade will depend on whether you were careful to save the config after you made configuration changes.

[Leo Laohoo]

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@mheddy439 wrote:

I have about 20 switches that need to have firmware updates

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Without any automation, like PI or DNAC, I can upgrade 20 switches in about 25 minutes.  

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@mheddy439 wrote:

What is the best way to do it? TFTP? USB?

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Both.  TFTP/HTTP for uploading from a central server and USB if the routers or switches boot into ROMMON.  

[Aijaz Rehman]

I will advise you to follow the below link for a step-by-step procedure on how to upgrade the iOS image for a Cisco SWITCH or ROUTER. Before proceeding with any configuration, make sure you have a copy of backup and  enough space on your switch/router to copy an image.

https://networklessons.com/cisco/ccna-routing-switching-icnd1-100-105/upgrade-cisco-ios-image