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Community Member

3750G stack compatibility

I know that idealy, all members of a stack should run the same IOS version and are the same model, but unfortunately, that's not always possible.

We currently have a WS-C3750G-24T-E, and I'm wondering if we can pair it up w/ a WS-C3750G-24TS-S1U and form a 2-switch stack?

I'll upgrade the existing switch from 12.1 to 12.2 code so that they have at least the same major version.


Re: 3750G stack compatibility

As far as I know you must have identical IOS version on all switches in a Stack

Let us know if you find a way to work around this.


Community Member

Re: 3750G stack compatibility

I can get the identical IOS; it's not a problem.

What I wanna know is if the two 3750's will form a stack since they're 2 different physical models.

Re: 3750G stack compatibility

Yes, it should but be aware of SDM mismatch as different 3750 modle might have different SDM default.

The Catalyst 3750-12S switch supports desktop and aggregator Switch Database Management (SDM) templates. All other Catalyst 3750 switches support only the desktop SDM templates.

All stack members use the SDM template configured on the stack master. If the stack master is using an aggregator template, only Catalyst 3750-12S switches can be stack members. All other switches attempting to join this switch stack enter SDM-mismatch mode. These switches can join the stack only when the stack master is running a desktop SDM template.

We recommend that your stack master use an aggregator template only if you plan to create a switch stack of Catalyst 3750-12S switches. If you plan to have a switch stack with different Catalyst 3750 switch models, configure the stack master to use one of the desktop templates.

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Community Member

Re: 3750G stack compatibility

thanks for the replies.

I was aware of the SDM mismatch.

Was gonna see anyone's actually built a stack w/ different models of 3750s cause the books aren't always 100% correct.

Cisco recommends using desirable for trunk ports, but at a remote site I was working on last month, the ports just wouldn't negotiate trunk unless they're hardcoded.

Super Bronze

Re: 3750G stack compatibility


It's no problem at all - the whole point of these switches is that you can mix and match to get whatever port types and density you need in a stack.

When you download the software there is only one image (well, 4 if you count EMI/SMI and crypto/non-crypto) for all the 3750 switches.

As long as all the switches are at the same version it will be fine. If it's not, the new switch probably won't boot up straight away - often they will auto-upgrade, if not you may have to manually tell it to do it.. you can just copy the software from your running switch with the 'archive copy-sw' command.



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Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
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