Date: Sun, 31 Jan 2010 08:34:48 +0100 From: Alexander Egorenkov <egorenar@googlemail.com> To: Sam Leffler <sam@errno.com> Cc: freebsd-net@freebsd.org Subject: Re: A-MPDU transmission in net80211 on FreeBSD 8 Message-ID: <2d3b7e441001302334t5baa1102pdd1ee0309d32c2fd@mail.gmail.com> In-Reply-To: <4B64FC76.5060506@errno.com> References: <2d3b7e441001271104j14836df4j14428d34561dead1@mail.gmail.com> <2d3b7e441001271108p2a40dbbbwaa6af9679d61ab@mail.gmail.com> <4B64FC76.5060506@errno.com>
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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@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@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. >>> >>> >>> _______________________________________________ >> freebsd-net@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-net >> To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >> >> >> >
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