Hostapd AP SSID broadcast problem

Pertti Niinimäki itprosenior at
Wed Nov 18 09:59:04 PST 2015

Thanks a lot - kiitos!
That was clear and exact answer to my question and problem.  I couldn’t
find any help from internet referring to this Beacon frames transmission
The adapter used is Ralink based Wi-PI dongle. It is using automatically
RT2800USB device driver.
Originally I had  driver option in hostapd.conf as driver=nl80211 (kernel 
interface ?)
Yesterday I did some fiddling with driver options and restarts.
Lsmod command is now  showing  mac80211 as loaded driver,
even current config  still specifies nl80211?

What is best – last night my  remote location wifi IPS camera been has woken 
up and
WORKS after more than one week.
May be there is some race condition which driver is picked up. Anyway 
seems to correct? I have to study this a bit more.
Thank you for the help – Hostap seems to be robust and versatile software.
I’m now much more aware of its capabilities.

Pertti Niinimäki

-----Alkuperäinen viesti----- 
From: Jouni Malinen
Sent: Wednesday, November 18, 2015 5:44 PM
To: PerttiNiinimäki
Cc: hostap at ; michael-dev at
Subject: Re: Hostapd AP SSID broadcast problem

On Wed, Nov 18, 2015 at 04:34:00PM +0200, Pertti Niinimäki wrote:
> From the Hostap source code I’ve been trying to identify, which are
> the preconditions and timing
> for 802.11 type broadcast beacons, but so far without success.

hostapd does not actually transmit the Beacon frames. It provides a
frame template to the kernel (driver or 802.11 stack) and the actual
transmission is coordinated by the WLAN driver (and/or firmware).

With some drivers (e.g., most drivers using mac80211), hostapd takes
care of Probe Request frame processing and sending of the Probe Response
frames (which have similar information to the Beacon frames).

Jouni Malinen                                            PGP id EFC895FA 

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