A-MPDU transmission in net80211 on FreeBSD 8

[Alexander Egorenkov]

And i took a look into the  802.11 stack of OpenSolaris which also supports
802.11n.
This 802.11n stack is very similar to the FreeBSD 802.11n stack and it
assigns sequence numbers to A-MPDU frames. I did it in my device driver like
802.11n stack from OpenSolaris does it.

See this link:
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/io/net80211/net80211_output.c

Line: 211

Alex.

On Sun, Jan 31, 2010 at 8:34 AM, Alexander Egorenkov <
egorenar at googlemail.com> wrote:

> 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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>>>
>>
>