topic Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI in Software-Defined Access (SD-Access)

SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

g.mantuano — Fri, 19 May 2023 15:56:02 GMT

Hi Folks,

As per my customer requirements, he need to transport external Legacy L2 VLAN through Layer2 handoff on any edge, without enabling a local border SVI for those VLAN's as SVI is on external Core not managed by this customer. Did someone know if it's feasibile ?

Appreciated if someone already tested a scenario like this

Many thanks.

Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

Flavio Miranda — Fri, 19 May 2023 17:34:30 GMT

This might help you

https://www.theasciiconstruct.com/post/sda_10/

Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

Andrii Oliinyk — Fri, 19 May 2023 17:56:09 GMT

I personally didnt test stuff like u need, but still precisely been studying possible scenarios. notice: there is no L2-handoff on the FE - it's only on BN.

L2handof is applicable when your Fabric populated with endpoints whose L3-gw is outside of Fabric & it's highly recommended to pull legacy L2 BD to BN..

if u need to interconnect physically separated parts of L2 BD it's also supported (see attachment for precautions & recommendations). What u have to be concerned of is the amount of MACs talking each to other across the Fabric. It's terminating FEs scalability-relevant topic. Unfortunately i dont have numbers for this. Also expect Fabric to bring a considerable delay in the communications between legacy LAN islands as LISP-driven L2 communications are poorly synchronized with legacy L2-switching.

In either case u will need to have L2VN with L2-flooding enabled: good reading to start with is here Solved: L2VNI with gateway behind a Border (DNAC 2.2.3.0+) - Cisco Community (dont be confused with BN mentioned in title :0)

Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

jalejand — Fri, 19 May 2023 17:59:40 GMT

Make an L2 Only subnet and configure the FE port as a trunk/server.

Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

g.mantuano — Mon, 22 May 2023 06:36:34 GMT

Thank you, I already went through this document, but I'm need to know if the transport of L2 from the edge to the Border L2 Handoffwill work in case of external SVI not managed by the border.

Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

g.mantuano — Mon, 22 May 2023 06:38:32 GMT

Thank you, I know border isthe only component used for the L2 handoff , but I'm need to know if the transport of L2 from the edge to the Border L2 Handoff will work in case of external SVI not managed by the border, i mean an SVI not be a part of the fabric and use tha fabric only for L2 transport.

Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

g.mantuano — Mon, 22 May 2023 06:40:11 GMT

Thank you, but in this specific csse fabric will act not only as campus but also as ISP, i mean we don't know the subnet and SVI is on provate cloud not on border.

Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

jedolphi — Tue, 23 May 2023 09:04:37 GMT

jalejand's answer is correct, create an SD-Access Layer 2 Virtual Network (aka "Layer 2 Only" ), in that case the Fabric Site will instantiate an access VLAN and an L2 LISP instance, there will be no SVI in the Fabric Site, just an L2 transport. Please note that this is not an L2 protocol tunnel, it will not tunnel STP, CDP, LLDP, etc. Otherwise you could consider it more or less as a Fabric-Site-wide VLAN.

L2VN for wired use cases was added in 2.3.3.3. L2VN for wired and Fabric-Enabled Wireless will be added in 2.3.5.3.

Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

jedolphi — Tue, 23 May 2023 09:03:25 GMT

Re: SDA L2 handoff to transport on edge Layer 2 vlan without BorderSVI

g.mantuano — Tue, 23 May 2023 09:20:00 GMT

Thank you so much for the precious help !