Uppgrading 3750E stack without interuption

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Mar 20th, 2009
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Is it possible to uppgrade IOS image on a 3750E stack and not restart the entire stack at the same time. What I want is to restart one member at the time and have full functionality at the other members. I got this message "Systems with incompatible software

have been added to the stack" and the switch will not enjoy the stack and do not do any traffic forwarding at the ethernet ports. And I can't administrate the switch by console port.

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lars.levin Fri, 03/20/2009 - 08:02
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Im sorry but I couldn't find anyting useful in that document. The big question is if it is possible to make the switch with never IOS to work whithout disconnect it from the stack.

Laurent Aubert Fri, 03/20/2009 - 09:37
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I think you have no choice but upgrading all the stack at the same time. Different version in the stack is not supported as the stack protocol version is different.

Use the archive download-sw command from the master:


If you do it from the master, the new software should be automatically copied to all the members of the stack:


Then reload all the stack


Leo Laohoo Sun, 03/22/2009 - 17:55
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Or you can reload one switch member at a time.

hobbe Thu, 03/26/2009 - 02:15
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As far as I know the general rule for this is NO You can not upgrade the switchstacks this way.

You can reload the different units as you wish, but if the software images are to different (minor vs major release) you will not get them to work in the stack.

That said answering your question we can now look for a workaround.

There might be some solutions that might help you such as reroute traffic using rapid spanning tree to a different stack.


you could use ports that are initially shutdown on another stack to reroute the traffic during the time the stack needs to shutdown.

This all depends on how the stack is connected and to what.

good luck


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