topic Lan Automation, enable multicast afterwards? in Software-Defined Access (SD-Access)

Lan Automation, enable multicast afterwards?

Infelicitas — Tue, 07 Jan 2025 07:12:04 GMT

Helloes.

We are slowly deploying a SDA-fabric with DNA-center. We've been mounting and adding switches with LAN automation for a while now, and I believe that not all of them were deployed with the "Enable Multicast" option during LAN Automation.

Is there a way to deploy it afterwards? I couldn't find a workflow for it and i'm having trouble finding much information about it at all.
What commands should you run on the switches to enable it, and what should you look for to verify that it's enabled?

Re: Lan Automation, enable multicast afterwards?

Andrii Oliinyk — Tue, 07 Jan 2025 08:32:26 GMT

right, you can automate underlay multicast only during LAN-A. but underlay multicast is not too complex for manual enablement.
if u still dont want to enable underlay multicast by hands u can utilize head-end replication (overlay MC over unicast in underlay) with workflow of MC configuration in Fabric provisioning. With ingress replication u have to worry about scalability though. Also for BUM-flood (L2-flood enabled VN) support in the LISP/VXLAN Fabric only native MC in underlay is n option.

Cisco SD-Access Multicast - Cisco Community

Re: Lan Automation, enable multicast afterwards?

Infelicitas — Tue, 07 Jan 2025 17:30:19 GMT

I don't mind doing manual config. It shouldn't be that many switches.
I just don't really know what is needed to "fit" with DNAC:s config.

I've looked some at the configs that are pushed with LAN automation and the resulting conf afterwards. So to enable it afterwards I should be able to just run that on the missing switches. But does DNAC have an entry in it's database about which switches has multicast, or is it dumb in that regard?

It should work to deploy native multicast in the fabric afterwards?

Re: Lan Automation, enable multicast afterwards?

Andrii Oliinyk — Tue, 07 Jan 2025 17:46:37 GMT

not sure i get your concerns. but yes, DNAC doesnt keep any data about MC in underlay unless LAN-A was leveraged for this.