Re: [DESIGN RFC v3] AP Architecture for Wi-Fi-8 Multi-AP Coordination (MAPC)

On 1/27/2026 5:57 AM, Johannes Berg wrote:
> On Thu, 2026-01-22 at 00:42 -0800, Abhishek Rajkapur Suryawanshi wrote:
>>> Taking this specific example, it basically says "FW sends a request to
>>> hostapd, hostapd does the handshake and installs the MAPC station. This
>>> is how we think we should handle the MAPC stations."
>>
>> hostapd controls and manages all MAPC related discovery and MAPC peer 
>> creation part. No trigger from firmware for MAPC Discovery Phase.
> 
> Seems to me you're splitting hairs. Clearly you have the *negotiation*
> trigger (NL80211_CMD_MAPC_NEGOTIATION_TRIGGER) prominently featured in
> the diagrams etc. Sure, it maybe that doesn't explicitly trigger
> *discovery*, but if hostapd doesn't already know about the station that
> the FW/driver is requesting a negotiation with, it probably also has to
> do discovery...
> 
> Anyway. I went to write a long email replying to some of your individual
> points but deleted it again, I feel it's not worth your and my time.
> 
> 
> Clearly, you have already decided on the architecture, and aren't
> sharing all of it, based on reasons you aren't really sharing either.
> Which is fine, I can't claim that we always share the full reasoning
> behind architecture decisions.
> 
> We should all still make it transparent _how_ it's intended to work, but
> that could also be just part of the documentation added to the kernel
> when adding the necessary APIs.
> 
> 
> Which then means that really in all the hundreds of lines of text you
> just wanted to ask whether or not "Option-A" or "Option-B" for handling
> the MAPC peers should be used, and I'd agree that duplicating APIs isn't
> good, i.e. taking "Option-A". Note we did something similar for NAN
> stations, even if they have different sets of attributes than regular AP
> client stations or mesh peers etc.
> 
> johannes

Based on your feedback, we re-evaluated and modified the architecture. 
Here hostapd along with MAPC discovery, will initiate MAPC negotiation 
with discovered APs based on programmed rules(hostapd.conf / hostapd_cli)
& the criteria specified in IEEE P802.11bn/D1.3, sections 37.14.1.3 and 37.14.2.
Additionally, a hostapd CLI command will be added to trigger MAPC negotiation 
for controller-managed APs.


Figure 1: MAPC Negotiation Sequence (ESTABLISHMENT/UPDATE)
---------------------------------------------------------
+----------------------------------------------------------------------+
|                          UHR AP-1                                    |
|  +---------+       +---------+       +---------+       +---------+   | +---------+
|  |         |       |         |       |         |       |         |   | |         |
|  | hostapd |       | cfg80211|       | mac80211|       |  wlan   |   | |  UHR    |
|  |         |       |         |       |         |       | driver  |   | |  AP-2   |
|  +----+----+       +----+----+       +----+----+       +----+----+   | +----+----+
|       |                 |                 |                 |        |      |
|  +----+---------------+ |                 |                 |        |      |
|  | init hostapd & HW  | |                 |                 |        |      |
|  | MAPC support update| |                 |                 |        |      |
|  +----+---------------+ |  MAPC Discovery |                 |        |      |
|       |                 |    Request      |                 |        |      |
|       |                 |(MAPC capability)|                 |        |      |
|       +-----------------+-----------------+-----------------+--------|------>
|       |                 |  MAPC Discovery |                 |        |      |
|       |                 |    Response     |                 |        |      |
|       |                 |(MAPC capability)|                 |        |      |
|       <-----------------+-----------------+-----------------+--------|------+
|       |                 |                 |                 |        |      |
|  +----+---------------+ |                 |                 |        |      |
|  |alloc sta_info store| |                 |                 |        |      |
|  |MAPC capa & params  | |                 |                 |        |      |
|  +----+---------------+ |                 |                 |        |      |
|       |                 |                 |                 |        |      |
|    +--+-----------------+-----------------+-----------------+---+    |      |
|    |                     MAPC PEER CREATE                       |    |      |
|    +--+-----------------------------------+-----------------+---+    |      |
|       |                 |                 |                 |        |      |
|  +----+---------------+ |                 |                 |        |      |
|  | Based on configs   | |                 |                 |        |      |
|  | and spec criteria  | |                 |                 |        |      |
|  | Initiate MAPC      | |                 |                 |        |      |
|  |   Negotiation      | |                 |                 |        |      |
|  +----+---------------+ |                 |                 |        |      |
|       |                 |MAPC Negotiation |                 |        |      |
|       |                 |     Request     |                 |        |      |
|       |               (scheme params & APID1)               |        |      |
|       +-----------------+-----------------+-----------------+--------|------>
|       |                 |                 |                 |        |      |
|       |                 |MAPC Negotiation |                 |        |      |
|       |                 |     Response    |                 |        |      |
|       |               (scheme params & APID2)               |        |      |
|       <-----------------+-----------------+-----------------+--------|------+
|       |                 |                 |                 |        |      |
|    +--+-----------------+-----------------+-----------------+---+    |      |
|    |                     MAPC PEER UPDATE                       |    |      |
|    +--+-----------------+-----------------+-----------------+---+    |      |
|       |                 |                 |                 |        |      |
|       |                 |                 |                 |        |      |
|       |                 |                 |                 |        |      |
|       v                 v                 v                 v        |      v
+----------------------------------------------------------------------+


Figure 2: MAPC Negotiation Sequence (TEARDOWN)
-----------------------------------------------------
+----------------------------------------------------------------------+
|                          UHR AP-1                                    |
|  +---------+       +---------+       +---------+       +---------+   | +---------+
|  |         |       |         |       |         |       |         |   | |         |
|  | hostapd |       | cfg80211|       | mac80211|       |  wlan   |   | |   UHR   |
|  |         |       |         |       |         |       | driver  |   | |   AP2   |
|  +---+-----+       +---+-----+       +---+-----+       +---+-----+   | +----+----+
|      |                 |                 |                 |         |      |
|      |                 |                 |                 |         |      |
|      |                 |                 |                 |         |      |
| +----+---------------+ |                 |                 |         |      |
| | Based on configs   | |                 |                 |         |      |
| | and spec criteria  | |                 |                 |         |      |
| |   Initiate MAPC    | |                 |                 |         |      |
| |    Negotiation     | |                 |                 |         |      |
| +----+---------------+ |                 |                 |         |      |
|      |                 |MAPC Negotiation |                 |         |      |
|      |                 |     Request     |                 |         |      |
|      |                 |   (TEARDOWN)    |                 |         |      |
|      +-----------------+-----------------+-----------------+---------+------>
|      |                 |                 |                 |         |      |
|      |                 |MAPC Negotiation |                 |         |      |
|      |                 |     Response    |                 |         |      |
|      |                 |    (ACCEPT)     |                 |         |      |
|      <-----------------+-----------------+-----------------+---------+------+
|      |                 |                 |                 |         |      |
| +----+----------------+|                 |                 |         |      |
| |If agreement count   ||                 |                 |         |      |
| |is zero for MAPC peer||                 |                 |         |      |
| |then initiate MAPC   ||                 |                 |         |      |
| |peer delete          ||                 |                 |         |      |
| +----+----------------+|                 |                 |         |      |
|      |                 |                 |                 |         |      |
|   +--+-----------------+-----------------+-----------------+---+     |      |
|   |                     MAPC PEER DELETE                       |     |      |
|   +--+-----------------+-----------------+-----------------+---+     |      |
|      |                 |                 |                 |         |      |
|      |                 |                 |                 |         |      |
|      |                 |                 |                 |         |      |
|      v                 v                 v                 v         |      v
|                                                                      |
+----------------------------------------------------------------------+

Abhishek