Best Practice for Connecting MS225 Stacks to MX250 in Active-Passive Mode

[ygurra1]

Hi everyone,

I am working on a setup involving three separate stacks of MS225 switches, which I plan to connect directly to MX250 devices configured in an Active-Passive mode. My approach is to connect two uplinks from each stack—one to the Active MX250 and the other to the Passive MX250.

Given that RSTP is enabled globally and at the port level with default settings, I want to ensure that this setup does not introduce any looping issues, especially considering that MX devices do not support LACP.

I would appreciate any insights or best practices from those who have implemented a similar design. Specifically, are there any considerations or configurations I should apply to prevent potential network loops?

Here it is my scenario:

Looking forward to your recommendations. 
Thanks in advance,

Regards

[AmitPanchal]

You can use this topology as well. This wont have any switching loops.

[KarstenI]

With a redundant setup, the most important part is the enabled native VLAN on the MX:

https://cyber-fi.net/index.php/2022/03/13/how-to-connect-the-meraki-mx-to-ms-switches/

If you have the same VLANs on all switches, you will face some extra challenges with unusual BPDUs as each Switch will see multiple other switches on each uplink:

https://documentation.meraki.com/MX/Networks_and_Routing/MX_Layer_2_Functionality#Spanning_Tree_Prot...

[RaphaelL]

You can check this document : https://documentation.meraki.com/MX/Deployment_Guides/MX_Warm_Spare_-_High_Availability_Pair

It is slightly more resilient than what you are describing.

You have to build your switch stacks with the lowest MAC on your top of the stack switch or your will end up with some weird behavior due to STP portId being the tie-breaker.

[PhilipDAth]

I wouldn't do this.

Hopefully, one of the stacks is near the MX250s.  Make that that stack the core switches.  Then, plug everything into the core switches.