Is STP/RSTP BPDU traffic on Meraki Switch exchanged on Management VLAN or Native VLAN ?

[Sakul]

I understand that Meraki Switch cannot configure for PVST or MST, and if we need to connect Meraki SW to 3rd party switches which run PVST/PVST+ or MVST, Meraki BPDU traffics will go through only VLAN1. 

In the environment where we mix Meraki switches with Cisco (using PVST+), do we need to assign VLAN1 on our Meraki Management VLAN or Native VLAN ?

note: I googled on many meraki documents but it only says "For the Meraki switch to participate in spanning tree within a PVST+ or Rapid-PVST network, a spanning tree instance must be active on VLAN 1 across all switches", but never say whether management or native vlan.

Thanks, Sakul

[JeroenVercoulen]

Take a look at   https://documentation.meraki.com/MS/Meraki_Campus_LAN%3B_Planning%2C_Design_Guidelines_and_Best_Prac...

I think this will explain it to you

[Sakul]

Thanks JeroenVercoulen for good source of document. Yes, the document stated that 

MS390 Specific Guidance

It's required to have the same native VLAN configured for all switches in a STP domain as a switch will only send (or listen to) backward compatible BPDUs (e.g. PVST, PVST+) on its native VLAN (which is VLAN 1 by default)

[IvanJukic]

Hi @Sakul ,

The BPDU's are exchanged on ALL VLANs; per the RSTP standard. That said, you can set up VLAN 1 like a Transit for PVST/PVST+. But it can get messy. It is recommended to use MST.

https://documentation.meraki.com/MS/Deployment_Guides/Advanced_MS_Setup_Guide#Protocol_interoperabil...

[Sakul]

Thanks IvanJukic,
Many company's practice is to avoid using VLAN1 for its native vlan. But when we need mix Meraki switches with PVST/PVST+/MST non-Meraki switches, our Meraki switches have to use VLAN1. So in this case, I think my question is should we set
a) Management VLAN = xxx, and Native VLAN =1
b) Management VLAN = 1, and Native VLAN = xxx
in order to work with those PVST/PVST+/MST non-Meraki switches.

[IvanJukic]

Agree with the native part. But here you would Tag VLAN 1 and not leave it native anywhere. It would need to be pruned from Access Ports to end devices, PC, Printers, etc. So you're after Option b.) 

MST is completely compatible with STP/RSTP. It is just an expansion to the protocol. It adds a per-VLAN Spanning Tree to better use the paths on each VLAN. Which is why it is recommended.

[Sakul]

I thought I have to go with option a)  ?
because BPDUs are sent untagged and Meraki said " for Meraki switches to participate in a spanning tree topology with PVST/PVST+ protocols, a spanning tree instance must be running on VLAN 1 of all switches"

[IvanJukic]

BPDUs are never sent untagged. It must have a VLAN-ID. So then yes, you must tag on the non-meraki switch Trunk ports. Which is more manual work to do and get working, and a pain to tshoot.. 

You don't have to use Option a. You mention the non-meraki switches can run MST. If you run the same Spanning Tree Protocol across all switches. Then it's very easy to design and tshoot. 

Here is the rest of the quote:

"MS series switches to participate in spanning tree a spanning tree instance must be running on VLAN 1 of all switches and VLAN 1 is allowed on all trunk ports running PVST+ so that BPDUs are seen by the Meraki switches in the topology."

[Sakul]

Am I right to say that
"non-Meraki PVST/PVST,MST (including Meraki MS390), send BPDUs on every VLANs. However, Meraki switches (except MS390) will only participate BDPU with those non-Meraki switches on its VLAN 1 Native VLAN"  
and Meraki Management VLAN purpose is not for exchanging BPDU.

[ww]

Stp topology only uses the native vlan.

So keep your native vlan consistent in your network.

Meraki Management vlan is just any ip that talks to the cloud. Not related to stp