Moving DHCP to L3 MS-425

[Chapelhill_IT]

We currently have an older MX-100 that is running VLANs / DHCP for the entire site.  We run about a dozen VLANs.  Currently the MS-425 is a L2 switch.  We have a pretty substantial inter-VLAN traffic flow and I'd like to move the DHCP / VLAN configuration from the MX to the MS.  What is the best process to make this change and minimize downtime?

Can i setup everything in the MS-425 first and let the MX keep handling the traffic and then make a hard change to the MS device?  From what i've read i only need to configure one access VLAN on the MX when all is said and done?

Thanks for the advice here.

[RWelch]

MX and MS Basic Recommended Layer 3 Topology 

I would definitely plan to make the change during a maintenance window or period in which won't impact a lot of users.  Be aware that when you make the change to select the unique client identifier there will be some client/device data will change in the dashboard.

[Chapelhill_IT]

Do i only keep the Management VLAN in the MX but move all VLAN / DHCP (including DHCP for management VLAN) over to the MS?  Referring to this article:

https://documentation.meraki.com/Architectures_and_Best_Practices/Recommended_Topologies/MX_and_MS_B...

Trying to make sure in the move i don't suddenly break access to switches if that makes sense.

[RWelch]

 

This is what your interface editor options will look like after you make the change to L3.

You will need to select the right switch, give it a name, VLAN, IP/Subnet and gateway.  You will set the DHCP parameters below that (DHCP settings).

MS Layer 3 Switching and Routing 

[RWelch]

If you are using existing IP subnet on the MX, you will need to delete it from the MX and move it to the MS.

[RWelch]

You can use the same login that you use for the Meraki Community page to view the L3 setup in the Meraki Learning Hub:

Learn more with this free online training course on the Meraki Learning Hub:

• Configuring Layer 3 Routing

[Chapelhill_IT]

Just went thru the Layer 3 routing course and it def helped clarify a few things.  I did come up with a few questions regarding affect on site to site VPN.  Responded to your direct message with that concern.

[Boomerang94]

@Chapelhill_IT although it is already mentioned in the article @RWelch has shared above, the overall idea is as follows:

- Carefully move all the vlans and their gateway IPs (except the MS management one) to the MS425 

- As you are moving these VLANs - ensure correct static route on the MX as well pointing towards the MS425 for the correct subnets.

- Once you MS switch is capable of handling most of the VLANs - only have one transit VLAN between the MX and the MS425. You can either do this via access port or trunk port with pruned VLANs. Also, ensure a static default route on the L3 MS towards the MX. 

- Ensure that the management interface and transit VLAN SVI of the MS425 are two different IPs and management interface points to MX as its gateway.

Although, I have seen some scenarios where the customers are using more than just 1 transit VLAN between MX and Layer 3 MS - and it does work but not considered as best practice. 

If you get into any complications when performing this task, just reach out to Meraki support via https://meraki.cisco.com/support/