Stacking issues between

[sertorivs]

We have currently a stack of 2 switches in production.

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 WS-C3750G-48TS 12.2(35)SE5 C3750-IPBASE-M
WS-C3750G-48TS 12.2(35)SE5 C3750-IPBASE-M

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In this stack we had before athird sw

WS-C3750G-12S 12.2(35)SE5 C3750-IPBASE-M

This switch is damaged and needs replacement.

Our questions are:
1. Can we still order a switch model no 3 with stack module and that IOS?
2. If not, a new generation of WS-C3750X-12S-S will work in this Stack?
If it will work, what IOSes we will need to put on the 3750G and on the 3750X?

Best Regards

[Mark Malone]

Hi

its all about whether the major / minor numbers match with each other that will give the compatibility between switches platforms , you can use a 3750x as long as those numbers match the stack will form

Major Version Number Incompatibility Among Switches

Switches with different major Cisco IOS software versions usually have different stack protocol versions. Switches with different major version numbers are incompatible and cannot exist in the same switch stack.

Minor Version Number Incompatibility Among Switches

Switches with the same major version number but with a different minor version number are considered partially compatible. When connected to a switch stack, a partially compatible switch enters version-mismatch (VM) mode and cannot join the stack as a fully functioning member. The software detects the mismatched software and tries to upgrade (or downgrade) the switch in VM mode with the switch stack image or with a tar file image from the switch stack flash memory. The software uses the automatic upgrade (auto-upgrade) and the automatic advise (auto-advise) features. For more information, see the "Understanding Auto-Upgrade and Auto-Advise" section.

To see if there are switches in VM mode, use the show switch user EXEC command. The port LEDs on switches in VM mode stay off. Pressing the Mode button does not change the LED mode.

You can use the boot auto-download-sw global configuration command to specify a URL pathname for the master switch to use to get an image in case of version mismatch.

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_55_se/configuration/guide/3750xscg/swstack.html#wp1223384

Major/minor doc

http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/ios-software-releases-12-4-mainline/whitepaper_C11-719867.html

[sertorivs]

Many thanks, But focus on the case the question is following

Can I join a WS-C3750X-12S-S in a WS-C3750G-48TS stack? What do I need? same IOS versions?

Regards.

[Mark Malone]

Yes you can and the major/minor numbers in the IOS code need to match for this to happen and for the stack to form , you can stack different platforms its the code that's matters if the numbers don't match the mixed platforms wont stack

If your is exactly the same it will stack , if there slightly off it may stack partially with some features  

the major/minor numbers are part of the ios code c3750e-universalk9-mz.122-55.SE8

[Joseph W. Doherty]

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Posting

As Mark has noted, yes you can mix "generations" of the 3750 series, you just need to insure their software will work across the stack, easiest accomplished when IOS version/release matches.

That said, when you add an -E or X 3750 to original 3750 series, StackWisePlus reverts to StackWise.  Also, the 3750G-12S has special SDM templates, unique to it, but if it was stacked with the other 3750Gs, you weren't using them.