L3 Routing Setup on MS and Catalyst Switches

[pBrain]

When setting up L3 routing on MS / Catalyst (Meraki) Switches with an MX, I am setting up 2 SVI's on the switch to start.

1 NET Management SVI for Management and 1 TRANSIT SVI for Inter VLAN Traffic and communicating with the Uplink MX.

Which of these two SVI's should be set up as the "Default Uplink"?

[RWelch]

The transit VLAN.

MS Layer 3 Switching and Routing 

[pBrain]

Thanks.  I am running into an issue where my L3 switches are displaying their IP addresses from the transit VLAN, and not from the management VLAN.

Is this by design?

[RWelch]

Here are a couple of other reference documents if interested with L3 setups.

Layer 3 Switch Example 

Hybrid Campus LAN Design Guide (CVD) 

[RWelch]

The Hybrid Campus LAN Design Guide (CVD) has two design options for your consideration:

Design and Configuration Guidelines

Option 1 -  STP Based Convergence with Native VLAN 1

Option 2 -  STP Based Convergence without Native VLAN 1

I typically choose to use Option 2 when deploying L3 interfaces but both options are there for your consideration.

I am running MS425s and keep the MTU at 9394 so your default MTU of 9198 should be ok.

[pBrain]

Also, the document states, "SVI MTU size is 1500".  Does this mean that I have to set the MTU for that whole L3 switch to 1500?  Currently our switches have a default MTU of 9198.

[alemabrahao]

When creating the first IPv4 interface on a switch, you will be prompted to enter a default gateway address. This is the next hop IPv4 address of another device on the network, used for any traffic that isn't going to a directly connected subnet or over a static route. This IP address must exist in a subnet with a L3 interface, and will be used for the default route next hop IP address.

[pBrain]

The reason I bring this up is because I have a Network management VLAN, that all other switches get their IP addresses from, but the core l3 switches are using the TRANSIT VLAN SVI IP Address instead.

I read somewhere that in the Meraki ecosystem, the management and transit VLAN's must be different.  Is that still the case?

[alemabrahao]

Can you share the document?

[pBrain]

While watching some Youtube videos on the subject and reading through the community posts.  This one in particular:

Solved: Separate VLAN for Transit VLAN versus Meraki Core switches management inte... - The Meraki C...

[alemabrahao]

Yes, that statement is correct.

You should use a VLAN that is not the default gateway for management.

[pBrain]

It's odd, because on one of the switch stacks, it takes the transit VLAN as the switch IP address, but on all the others it uses the Net Management VLAN.