topic Re: C9800-CL multiple VLAN SVIs same mac in Wireless

C9800-CL multiple VLAN SVIs same mac

Clem58 — Wed, 22 Mar 2023 15:06:26 GMT

Hello,

I've deployed a C9800-CL Hyperv VM, I have created 2 VLAN SVIs, they got the same mac address.

Is this something normal ?

Thanks by advance

Re: C9800-CL multiple VLAN SVIs same mac

Scott Fella — Wed, 22 Mar 2023 15:10:23 GMT

When I have deployed the 9800-CL, I only used one SVI and that was used for management and wireless. What is the reason you need to have more than one? I'm just curious.

Re: C9800-CL multiple VLAN SVIs same mac

Clem58 — Wed, 22 Mar 2023 15:17:13 GMT

I need to add one for using central switching (guest access)

Re: C9800-CL multiple VLAN SVIs same mac

Scott Fella — Wed, 22 Mar 2023 15:29:06 GMT

So you are implementing FlexConnect, but you want to tunnel guest back to the 9800 VM? Why not just keep the guest local and use vrf to isolate that traffic.

Re: C9800-CL multiple VLAN SVIs same mac

Clem58 — Wed, 22 Mar 2023 15:35:08 GMT

There is no guest local, for 2 sites, so I need to use the guest where the
WLCs are connected.

Anyway we have the possibility to create multiple SVIs, so realizing they
have the same mac, I wonder if this is something intended by Cisco ?

Re: C9800-CL multiple VLAN SVIs same mac

Scott Fella — Wed, 22 Mar 2023 16:03:37 GMT

No idea because you typically don't need to configure an SVI on the 9800 for clients. Just pass the vlan tag and let the upstream L3 do the routing.

https://www.cisco.com/c/en/us/products/collateral/wireless/catalyst-9800-series-wireless-controllers/guide-c07-743627.html#Wirelessclientinterfaces

Re: C9800-CL multiple VLAN SVIs same mac

Clem58 — Wed, 22 Mar 2023 16:08:00 GMT

Ok yes you're right Scott, I wanted to add this svi to be able to ping the router that is in this VLAN, for checking, to be sure connectivity was working.

I saw this same mac for the both mgmt vlan and guest so that was my question 🙂

Re: C9800-CL multiple VLAN SVIs same mac

Scott Fella — Wed, 22 Mar 2023 16:16:49 GMT

I would have to say that it is by default since you have seen it. I have also added an SVI on my home lab 9800 and the Mac address is the same.

Re: C9800-CL multiple VLAN SVIs same mac

Clem58 — Wed, 22 Mar 2023 16:20:17 GMT

Thanks Scott !