topic Re: Layer 2 Border node ethernet map-cache in Software-Defined Access (SD-Access)

Layer 2 Border node ethernet map-cache

Jakob Mellberg — Wed, 04 Oct 2023 14:21:26 GMT

Hi!

We have deployed a stacked 9500 as our layer 2 border node, configured with lan-automation and have an issue with migrating wired clients.

We have a solution where clients authenticate with MAB over ISE and can migrate their wired connection to other buildings or offices.
When a client that uses a layer 2 vlan, not an anycast gateway network it works if the client have not been connected before.
But migrating a wired connection from one switch to another switch DHCP packets are being lost on the way back.

Looking on the layer 2 border node the ethernet map-cache locator for that mac-address points to the previous switch it was connected to, when manually clearing that cache-entry the layer 2 border node recreates the map-cache and gets the correct locator and sends the return data to the correct switch.

I have verified that the edge-nodes are sending deregister events to the control plane nodes for the mac-address. But the layer 2 border nodes seems to not be aware of this and keeps the ethernet map-cache towards the previous switch. The expire-time is very long on the layer 2 border node for ethernet map-caches, 24H.

Is there something I have missed when deploying the border node?

Are anyone of you aware of some good workaround?

Re: Layer 2 Border node ethernet map-cache

Jakob Mellberg — Fri, 06 Oct 2023 06:39:09 GMT

For anyone having the same issue.

It looks like this bug was the cause: https://bst.cloudapps.cisco.com/bugsearch/bug/CSCwc71236.

We updated all our switches to 17.9.4 and now when we disconnect device the map-cache updates on the border node correctly.

Re: Layer 2 Border node ethernet map-cache

Andrii Oliinyk — Fri, 06 Oct 2023 06:59:22 GMT

thanks for input, Jakob.
One Q pls: is you L2-handoff BN also configured as MSMR for the LISP L2VN-services on your Fabric Site?

Re: Layer 2 Border node ethernet map-cache

Jakob Mellberg — Fri, 06 Oct 2023 08:07:07 GMT

I have two dedicated control plane nodes. Our border nodes are not map-servers