Date: Wed, 27 Jan 2010 20:08:06 +0100 From: Alexander Egorenkov <egorenar@googlemail.com> To: freebsd-net@freebsd.org Subject: Re: A-MPDU transmission in net80211 on FreeBSD 8 Message-ID: <2d3b7e441001271108p2a40dbbbwaa6af9679d61ab@mail.gmail.com> In-Reply-To: <2d3b7e441001271104j14836df4j14428d34561dead1@mail.gmail.com> References: <2d3b7e441001271104j14836df4j14428d34561dead1@mail.gmail.com>
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Sorry, i posted the wrong comment.
Here is the comment which i don't understand:
/*
* NB: don't assign a sequence # to potential
* aggregates; we expect this happens at the
* point the frame comes off any aggregation q
* as otherwise we may introduce holes in the
* BA sequence space and/or make window accouting
* more difficult.
*
* XXX may want to control this with a driver
* capability; this may also change when we pull
* aggregation up into net80211
*/
Thanks.
On Wed, Jan 27, 2010 at 8:04 PM, Alexander Egorenkov <
egorenar@googlemail.com> wrote:
>
> Hi,
>
> i'm implementing a device driver for a 802.11n NIC under FreeBSD 8
> und experimented with A-MPDU transmission. I looked into net80211 code
> and there is some code which implements this feature but it worked not very
> well for me.
> I noticed e.g. that sequence numbers are not assigned to A-MPDU frames
> and found this comment in file ieee80211_output.c :
>
>
> /*
> * Check if A-MPDU tx aggregation is setup or if we
> * should try to enable it. The sta must be associated
> * with HT and A-MPDU enabled for use. When the policy
> * routine decides we should enable A-MPDU we issue an
> * ADDBA request and wait for a reply. The frame being
> * encapsulated will go out w/o using A-MPDU, or possibly
> * it might be collected by the driver and held/retransmit.
> * The default ic_ampdu_enable routine handles staggering
> * ADDBA requests in case the receiver NAK's us or we are
> * otherwise unable to establish a BA stream.
> */
>
> Can somebody elaborate this description to me please.
>
> Thanks.
>
> ALex.
>
>
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