STP root bridge change

Unanswered Question
Nov 22nd, 2009

Hi,

If in a already converged STP network if we introduce a new switch with lower priority will it force the full network to run the STP all again?

Or STP will hold the currently elected root as the root bridge even after adding a new switch with lower priority? In this case how do we force all switches in the network to recalculate new root bridge? Does this recalculation has a big impact on network or it is recomended to do the activity only with scheduled down time?

Please share the experience.

Any link on cisco.com?

Thanks in advance

Subodh

I have this problem too.
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Jon Marshall Sun, 11/22/2009 - 10:11

bapatsubodh wrote:

Hi,

If in a already converged STP network if we introduce a new switch with lower priority will it force the full network to run the STP all again?

Or STP will hold the currently elected root as the root bridge even after adding a new switch with lower priority? In this case how do we force all switches in the network to recalculate new root bridge? Does this recalculation has a big impact on network or it is recomended to do the activity only with scheduled down time?

Please share the experience.

Any link on cisco.com?

Thanks in advance

Subodh

Subodh

A switch with a lower priority will indeed force the network to reconverge. If it has a lower priority than any existing switch then yes it will become the root bridge.

Definitely do this in a scheduled downtime, you do not want an STP reconvergence during core production hours.

Jon

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