How to disable the ProCurve 6120 XG from becoming Spanning Tree root??

[chuckk281]

Karl was looking to help a customer:

****************

A customer has several ProCurve 6120 XG switches in several c7000’s connected to Brocade 1600 SX.  The ProCurves are trying to become the root Spanning Tree.  Is there a setting or way to keep them from doing this.

Firmware on the ProCurves Z.14.27 ROM: Z.14.09

*************

Yoshi suggested:

***************

Did you check the STP priority value on both switches? 

In STP environment, switch has a highest bridge priority(=lowest value) become the root bridge.

Default bridge priority of the Brocade SX switch is 32768(P.279).

http://www.foundrynet.com/services/documentation/fastiron_config/07100/FastIron_07100_ConfigGuide.pdf

 If you set 6120XG to higher priority value than Brocade, 6120XG wouldn't be the root.

Please check the actual value before you change the configuration.

***************

Dan also had replied:

*************

So would I be correct in assuming an alternate fix would be to lower the number on the Brocade side so it's less than whatever the 6120XG's default is?

Seems like if you only have 1 or 2 Brocades and a growing number of 6120XG enabled enclosures, that might be an easier fix.

****************

Other suggestions or comments?