Cisco 3750 Stack with different IOS

[fgasimzade]

    I have just configured a stack of 2 Cisco 3750 switches, and everything works fine

Switch/Stack Mac Address : 001c.577d.7b80

                                           H/W   Current

Switch#  Role   Mac Address     Priority Version  State

----------------------------------------------------------

*1       Master 001c.577d.7b80     2      0       Ready             

2       Member 001f.9d79.5d80     1      0       Ready             

The only consern is that two switches have different IOS

Switch   Ports  Model              SW Version              SW Image           

------   -----  -----              ----------              ----------         

*    1   12     WS-C3750G-12S      12.2(35)SE2             C3750-ADVIPSERVICESK

     2   12     WS-C3750G-12S      12.2(35)SE5             C3750-IPBASE-M     

As far as I know all the switches in the stack need to have the same IOS version. How is this possible then in my case that 2 switches with different IOS formed a stack with no problems?

Thank you!

[Karsten Iwen · Accepted solution]

The legacy 3750 allowed to have different versions (up to a certain degree) and even different feature-sets. That allowed you to have for example a stack of eight switches, but only two of them run the more expensive IP-Services image while the others only have the base image. In scenarios like this you have to make sure that the stack-master is always a switch running the highest feature-set.

More informatio on that topic is in the documentation:

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_35_se/configuration/guide/swstack.html

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[Leo Laohoo]

I have just configured a stack of 2 Cisco 3750 switches, and everything works fine

Try turning OFF switch 1 and see if your configuration works.