Spanning Tree question

[FREYA]

I have following Meraki switch ,

MS350  stack- Site core

MS 210 stack - Site Access

MS 425 - DC core

site core to DC core is connected via dark fibre on vlan 912

Site core connected to FW for the routing. Data, voice and Wireless VLAN. 

Till I have connected the switch to the DC on Vlan 912 things are working good.. but now as soon as I have connected the DC switch it took over the RSTP root role.  Every testing or any changes on DC switch or that link is now causing the RSTP election resulting 15 second outage. 

I do not want DC switch to be root for the site. I want Site core switch to be the root no mater what. 

as there are 3 more sites going to connect to the DC as well. 

I couldn't find any settings on the site switch portal to change the priority to make it root.. 

Any suggestion will be good. I think the MS425 has the switch > configuration tab to change the priroty.  I believe all the priority are set the default. 

Any advice will be good as I need to find the solution before I commission more sites. 

Thank you.

[FREYA]

MS350 - STP priority set to 4096 

DC switch MS425 STP Priority is default.

[alemabrahao]

Take a look at the documentation.

https://documentation.meraki.com/MS/Port_and_VLAN_Configuration/Configuring_Spanning_Tree_on_Meraki_...

[FREYA]

I do not see the option. 

[RWelch]

Chances are that this specific login (user permission) is a Read-Only or Monitor-only account.  

It would need "full" network admin permission or organization admin permission.

[RWelch]

 

The image above indicates you can't see the Switching > Configure > Switch Settings option but once you do the settings you are looking for would be similar to the image above with your MS350 listed at 4096 per your preference.  

Or you can look at adjacent switches to see which switch is the RSTP Root as an example below.

 

[PhilipDAth]

On another note; Meraki uses the untagged VLAN for spanning tree packets.  It is safer if everything agrees to this being the same VLAN.  It is safest to make this VLAN1.

So on your dark fibre, I would make the native vlan 1, and allow VLANS 1 and 912.

[FREYA]

I have made it as an access port. I have found one issue, where DC switch is advertising root with priority 0 o to the site. DC switch indicates that Root is connected to port 29. however there is no such mac address is connected to port 29. Given mac address starting with  ( 00 18 0a) is nowhere to be found. It is Meraki Mac address and I have checked all the devices ( there is only 4 devices) connected to port 29 via Layer 2 circuit. 

[FREYA]

We are working to implement the following topology, 

•  5 sites with the core as Meraki Stack switch
• Each site uses the dark fibre between the site and the data centre1 and data centre 2 and transit VLAN. 
• Data centre 1 and data centre 2 is also connected with each other via dark fibre. 
• Each site has the FW connected to core switch which is the L3 gateway of the site. 
• All the access switches connect to core switch. 
• Some sites may have multiple connections to the single DC switch expect given single link with different VLAN .. For example, vlan 100 - primary , and vlan 110 secondary on Fibre 1. While the fibre 2 will have VLAN 900 for special purpose Transit VLAN. 

• Looking to make sure each site core switch is their own STP root. 
• Either to remove the DC core switch from the STP election process to break the STP domain or alternative suggestion. 
• Other option is to make DC1 as primary root and DC2 as secondary root for all the sites. But due to the WAN connection I am not keen to perform that task. 
• Per VLAN Spanning Tree is another option but I do not see that is supported on Meraki platform.