A-MPDU transmission in net80211 on FreeBSD 8

[Alexander Egorenkov]

Why doesn't 802.11 stack assign sequence numbers to A-MPDU frames ?
When sequence numbers are not assigned to A-MPDU frames, then BA doesn't
work with my AP.
I tried to assign sequence numbers to A-MPDU frames in my device driver and
then BAs worked
with my AP.
And what is meant by aggregation queue ? Where is that queue anf how do i
use it ?

Thanks.

On Sun, Jan 31, 2010 at 4:43 AM, Sam Leffler <sam at errno.com> wrote:

> Alexander Egorenkov wrote:
>
>> 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.
>>
>
> What is unclear?
>
>        Sam
>
>
>>
>> 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.
>>>
>>>
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>>
>