A-MPDU transmission in net80211 on FreeBSD 8

[Alexander Egorenkov]

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 at 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.
>
>