How to change port priority for STP?

[NadiaK]

Is it possible to change switch port priority for STP?

I found only bridge priority configuration which affect to root-bridge election.

But I would like affect to root-port election. 

Some network equipment allows to change port priority, but I don't see this possibility for MS-120.

Can I do it?

Thank you in advance

[Bruce · Accepted solution]

Changing the bridge priority on the switch is the only STP customisation you can do, effectively ensuring you can choose the root bridge. You can’t change individual port priorities.

What is the reason you need to do this?

[NadiaK]

Thank you for your answer.

> What is the reason you need to do this?

To control traffic path and avoid situation like this (I had it without any physical issues with links and ports):

Unfortunately I cannot configure MX as a root bridge, because "The MX does not run STP in any capacity, and will not exchange BPDUs with other switches or partici...

So I hoped to control my active topology by port priority.

[Bruce]

@NadiaK, yep, you are completely correct about the MX. Although the MX doesn’t generate its own BPDUs, it does forward BPDUs that it receives out other ports. You’re limited to how you can influence the traffic flow to just modifying the root bridge priority on the switches.