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From: Christian Lamparter <chunkeey@googlemail.com>
To: Yingang Fu <yingang.fu@gmail.com>
Cc: linux-wireless@vger.kernel.org
Subject: Re: AP send null-data packet?
Date: Mon, 20 Feb 2012 10:48:01 +0100	[thread overview]
Message-ID: <201202201048.01883.chunkeey@googlemail.com> (raw)
In-Reply-To: <CAHPDcRtEHP7LAGPDE_UDs-P9Nq_ZrQbxsMYDCt-eXvjR+5=6kQ@mail.gmail.com>

On Monday, February 20, 2012 08:12:34 AM Yingang Fu wrote:
> It is wired that my AP send the station a null-date packet.
> As i know that this packet could only been sent by the station.
> Under which case the AP will send out this type of packet?

Don't know much about other AP software. But hostapd sends them
to check if a station is still in range and active.

quote from hostapd.conf:

# Station inactivity limit
#
# If a station does not send anything in ap_max_inactivity seconds, an
# empty data frame is sent to it in order to verify whether it is
# still in range. If this frame is not ACKed, the station will be
# disassociated and then deauthenticated. This feature is used to
# clear station table of old entries when the STAs move out of the
# range.  

Regards,
	Chr

  reply	other threads:[~2012-02-20  9:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-20  7:12 AP send null-data packet? Yingang Fu
2012-02-20  9:48 ` Christian Lamparter [this message]
2012-02-20 11:03   ` Mohammed Shafi
2012-02-20 11:05     ` Johannes Berg
2012-02-20 11:11       ` Mohammed Shafi

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