SDA Wireless Client Roaming

[JUANNN]

Hello,

I am trying to clarify a little doubt. Considering that I am using SDA with LISP Pub/Sub Model, when a client roams (either Wired or Wireless), is the CP going to publish the L2 and L3 Client address+ new RLOC entries to all subscribed nodes (this is, to BN and to EN that sent a Map-Request for such client address previosuly and whose "subscription" is still active)? I know that for wireless is the WLC the one that first notifies the CP and all that. The point of this question is at the end, when both wired and wireless roaming get to the same point where the new Edge Node has registered both the MAC and IP of the client to the CP.

I feel like this is what makes most sense. But I see for example the following documents:

- https://www.ciscolive.com/c/dam/r/ciscolive/global-event/docs/2025/pdf/BRKENS-3826.pdf
- https://www.ciscolive.com/c/dam/r/ciscolive/emea/docs/2026/pdf/BRKEWN-3515.pdf

both showing a Solicit Map Request sent by the "new EN" to "inform the remote ENs about the roam" (basically, telling them the new RLOC). Is this expected behavior with LISP Pub/Sub, so Publications only apply to BNs?

[M02@rt37]

Hello @JUANNN 

Just one nuance, LISP Pub/Sub is not limited to BNs. With EID pub/sub, an EN can subscribe to remote EIDs it has previously resolved... so when a client roam and the CP learn the new EID > RLOC, the CP can publish the new mapping to subscribed ENs (and BNs).

The solicit map-request shown in the Cisco Live slides you share is a separate mechanism .... I mean it is used by the new EN to trigger remote mapings and does not mean that publications are restricted to BNs...

[Andrii Oliinyk]

"is the CP going to publish the L2 and L3 Client address+ new RLOC entries to all subscribed nodes (this is, to BN and to EN that sent a Map-Request for such client address previosuly and whose "subscription" is still active)?" - only Cisco knows) but i'd expect it to be in compliance to PubSub rfc9437
"...both showing a Solicit Map Request sent by the "new EN" to "inform the remote ENs about the roam" (basically, telling them the new RLOC). Is this expected behavior with LISP Pub/Sub, so Publications only apply to BNs?" - SMR (rfc9301) has nothing to do with PubSub. they may coexist though.

[Jhonbruce]

I think the key distinction here is that PubSub notifications are driven by the subscription state maintained by the Map-Server. If the BN/EN has an active subscription for the EID-prefix, the Map-Server should notify each subscribed xTR when the mapping

[Andrii Oliinyk]

they are (among with mobility events). & notifications are implemented via Map-Notify messages in PubSub.

[Andrii Oliinyk]

to sum up. i reread 2.3.7x-3.2x manuals. conclusions:
Pub/Sub is enabled/configured at the CP/fabric level.
BNs are explicit Pub/Sub subscribers.
There is no obvious per-EN/per-EID configuration knob.

so far this Pub/Sub functionality for EN in SD-Access Solution Design Guide sound like marketing buzz.
& answer is mobility events in 2.3.7x SDA fabric still convey via SMR unless it's about BNs.

[JUANNN]

Mmmm... interesting. I will have to lab this once I get my DNAC back up again and see if the CP actually publishes to BN and to ENs about the roaming update, or just to BNs...

[Andrii Oliinyk]

lab is free to grab https://devnetsandbox.cisco.com/DevNet/catalog/catalyst-center-sandbox_catalyst-center. but C9Kv SW there is most likely 17.12.01.prd9 (meaning EN... can subscribe to active remote EIDs will not be effective)