Enable Layer 3 feature on MS Switch which is correctly working as Layer 2

[NAS]

Hi Folks,

I have a Meraki MS 355 switch, which is currently working as a Layer 2 switch. It is currently placed in between two Catalyst Layer 3 switches, and Catalyst switches are communicating via this Meraki switch. There are some VLANs permitted on multiple Meraki ports. Will the current connection between the catalyst switches be impacted if I enable the Layer 3 feature on Meraki?

Thanks,

NAS

[alemabrahao]

It depends, if you configure it for the same VLAN that already exists in the Catalyst Switch, it is likely that there will be an election of the ROOT STP.

Excuse the question, but I believe that the Catalyst Switch is your network core, why do you intend to enable L3 in MS?

Remember to check if the STP is properly configured.

[NAS]

We are planning to create new VLAN interfaces on Meraki. Hope that will not make any impact the connection between catalyst.

The catalyst switches are old 3750 series and we are planning to replace those with the Meraki later.

[PhilipDAth]

> It is currently placed in between two Catalyst Layer 3 switches,

If it is between two Catalyst switches then it is very important to change both of those switches to using mst.
spanning-tree mode mst

Once you have done that you can create L3 VLANs on the Cisco Meraki switches at will.

[cmr]

Make sure you have the latest firmware, there were a load of bugs about adding and deleting SVIs on 355s.  15.20 or later is needed to not fall foul of them.