Is there a service interruption if you change the root bridge?

[Announcer]

After taking some Meraki learning hub courses, I've noticed that our slowest switch 10/100 is the root bridge.  If I want to change this to the core Meraki switch, will there be a service interruption at all?

thanks.

[GreenMan]

Yes - assume there will be a network-wide outage

[cmr]

In theory it should only last about 30 seconds, but plan for a few minutes.

[DarrenOC]

Hi @Announcer , The network will need to re-convergence once you change the Root Bridge.  From your new Root make sure you configure the uplinks from this switch to the upstream switches to STP Guard - Root Guard.  Then downstream from the edge to core uplinks set those to STP Guard - Loop Guard

[Brash]

When changing root bridge, from my experience there may not always be an outage, but always assume there will be and prepare accordingly

[GIdenJoe]

As long as you don't have a circle of switches the outage should be quite minor.

RSTP reconverges by blocking the links between two switches while sending a proposal BPDU and the other switch should immediately send a response if it agrees.

If you have a good star topology the outage should be minimal (less than 2 seconds).  If you have a circle you could experience a count to infinity issue where you go down for a while before the topology can resolve itself.