MS390 as a new core

[Dave_S]

We currently have a core switch stack made up of 3 aging 24port 3870s.  We wanted to install 2 MS390-48s in a stack, and move our core switch functionality over to the new MS390 stack.  I am having a hard time finding documentation showing me how to set the Meraki stack to have the same functionality as the 3850 stack.

David S.

[DarrenOC]

Hi @Dave_S , what functionality are you looking to configure?

[DarrenOC]

@Dave_S , a good place to start:

https://documentation.meraki.com/MS/MS_Installation_Guides/MS390_Series_Installation_Guide

[Dave_S]

In our current 3850 stack, we have a number of VLANs defined, login to the stack is via RSA(my understanding is that on Meraki, we need to use Duo), have a number of Port-channels defined as links to wiring closets, has some static routes defined, and access lists to some VLANs and some by protocol.  

I have never set up a core switch before, and this new Meraki stack will replace the 3850 stack.  I'm trying to verify if this is a feasible switch, and how to do it properly.  Currently I'm waiting for my secondary power supplies, stacking and power stacking cables to be able to create the stack.  Then I need to nail down the steps to take to switch over, and some way to test without breaking the network.

Up till now, I've only deployed layer 2 switches, so this is all new to me.

[DarrenOC]

hi @Dave_S , you've honestly got nothing to worry about.  The biggest step up from Layer 2 to Layer 3 are your VLAN's and routing.  Take a snapshot of these from your existing core noting the VLAN ID, description and any IP-Helpers.  Then note the uplinks from the existing core, I would presume these are Trunks with a Native VLAN and as you've already stated they're Ether-Channeled.  Is your existing core providing DHCP services at all?  If so, note those down and replicate onto the new core.

Whilst I don't like the MS390's they're a suitable replacement for the Catalyst 3850's. 

With regards setup and migration.  I would bring each new ms390 online and register out to the cloud.  once registered I would configure and build the stack.  You could do this in isolation of your main network just to ensure STP doesn't throw a hissy fit.  I would then replicate your existing config onto the new core stack.  once happy schedule in a migration time and date.

[PhilipDAth]

MS390s have a bad reputation - I would avoid using them if you can.

As you the migration, you are going to need to go through the 3850 stack config item by config item, and re-implement in the Meraki dashboard.

[Dave_S]

Can't avoid.  they are what we have, so we'll have to see how it goes and make the best of it.  I have been going over the current core config with a fine-toothed comb, so I can replicate as much as possible on the Meraki stack. The only issue is the difference in terminology between the two sometimes make it confusing in translation.