RSTP loops

Hi,

I have this topology:
RTSP.png
This is a bridged net with RSTP. I would like to use dashed lines as backup links.
When I put the main links to the bridges it works well. When I put BD link - B bridge marks BD path as alternate root and it works well.
When I put the CD port to the bridges it logs loop and the traffic stops.
Is there any way to put all my backup links to this one bridged network?

best regards, Gabor

Hello, this should work (assuming all interfaces got the same cost):
1.- Make C the root bridge (reduce its bridge priority).

2.- Increase the cost of D interface going to C and D interface going to B to something higher than the sum of D to A, A to B and B to C interfaces.

Enviado desde mi MotoE2(4G-LTE) mediante Tapatalk

Hi,

thank you for your answer!
I have already modified the path costs.
I tried to change the root bridge to B or C but I got loop always when I put more than 1 backup link.

regards, Gabor

Set Horizon different in Bridge - port

Double check rstp is active in the bridge. This shouldn’t be happening if it is

Enviado desde mi MotoE2(4G-LTE) mediante Tapatalk

Hi,

I think I found the problem… Between B and C I have a Racom ray2 24G bridge. It doesn’t forward BPDU packets somehow. So C, E and F has an other root bridge in the same bridge…
Next night I will enable RSTP in racoms (although doc says racom forward BPDU packets transparently when rstp is disabled).

thank you all, Gabor