IOS Version Question

[kpieckiel]

Greetings!

I just bought some Catalyst 3560-X switches that came with IOS 12.2(55)SE3 on them.  I'm definitely a proponent of not fixing things that aren't broken when devices are in production, but I was going to at least upgrade to 12.2(58)SE2 before deployment to ensure I have the latest bugfix release in this version tree.

I noticed that 15.0(1)SE2 was also available, so for grins I compared the two versions in the feature navigator.  As it turns out there aren't any feature differences between the two and the memory requirements are the same.

For most software the higher version numbers mean more features or better compatibiliity or somesuch.  With IOS--at least with this comparison--that doesn't seem to be the case.  Why are these two releases the same, and why would I or would I not want to put the 15.0 image on my switches before deployment?  Why did Cisco decide to preinstall 12.2 instead of 15.0?

Sometimes I just don't understand Cisco's version numbering or IOS version selection for their products.

[fb_webuser · Accepted solution]

Well... Cisco introduced the version 15.x that works with licences, the ios package comes with all the features but are locked, and you can unlock it with a license.

Cisco preinstalled the version 12.2 because it was the stable version leaving the factory? Who knows?

But beware of upgrading any router/switch, because the equipment after being upgraded can´t roolback to a version inferior like 12.4 or something alike.

Check if yor ios in version 15.x don´t have any bug, that won´t compromisse your solution.

I hope that it helps.

but for more info:

http://www.cisco.com/en/US/docs/ios/csa/configuration/guide/csa_overview.html

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Posted by WebUser Pedro Seabra Ávila from Cisco Support Community App