Return-path: Received: from nbd.name ([46.4.11.11]:46350 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752746Ab2GPTYj (ORCPT ); Mon, 16 Jul 2012 15:24:39 -0400 Message-ID: <50046A71.9020302@openwrt.org> (sfid-20120716_212442_471283_2A92AC1A) Date: Mon, 16 Jul 2012 21:24:33 +0200 From: Felix Fietkau MIME-Version: 1.0 To: Sujith Manoharan CC: "linux-wireless@vger.kernel.org" , "linville@tuxdriver.com" , "Rodriguez, Luis" Subject: Re: [PATCH v2 08/12] ath9k: fix aggregate size limit based on queue TXOP limit References: <1342105451-42297-1-git-send-email-nbd@openwrt.org> <1342105451-42297-2-git-send-email-nbd@openwrt.org> <1342105451-42297-3-git-send-email-nbd@openwrt.org> <1342105451-42297-4-git-send-email-nbd@openwrt.org> <1342105451-42297-5-git-send-email-nbd@openwrt.org> <1342105451-42297-6-git-send-email-nbd@openwrt.org> <1342105451-42297-7-git-send-email-nbd@openwrt.org> <1342105451-42297-8-git-send-email-nbd@openwrt.org> <20481.3065.540576.366365@gargle.gargle.HOWL> <500143CA.1020804@openwrt.org> <506697F5827BD842B7CB80D046EBE618995399@aphydexd01b> <5002A7B2.409@openwrt.org> <20483.52640.521243.418804@gargle.gargle.HOWL> <5003EABD.5040506@openwrt.org> <20484.23881.582002.607413@gargle.gargle.HOWL> In-Reply-To: <20484.23881.582002.607413@gargle.gargle.HOWL> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2012-07-16 8:28 PM, Sujith Manoharan wrote: > Felix Fietkau wrote: >> The standard does not say anything specifically about A-MPDU, but it >> does say this: >> >> When the TXOP limit is nonzero, a STA shall fragment an individually >> addressed MSDU so that the transmission of the first MPDU of the TXOP >> does not cause the TXOP limit to be exceeded at the PHY rate selected >> for the initial transmission attempt of that MPDU. The TXOP limit may be >> exceeded, when using a lower PHY rate than selected for the initial >> transmission attempt of the first MPDU, for a retransmission of an MPDU, >> for the initial transmission of an MPDU if any previous MPDU in the >> current MSDU has been retransmitted, or for group addressed MSDUs. When >> the TXOP limit is exceeded due to the retransmission of an MPDU at a >> reduced PHY rate, the STA shall not transmit more than one MPDU in the TXOP. > > Um, am not sure how this passage relates to number of subframe calculation in an > aggregate ? The way I understand this, the TXOP limit is meant to limit the duration of a single transmission on the channel. An aggregate is transmitted in one go, there's no SIFS or extra PHY headers inbetween, just short delimiters. So an A-MPDU should be treated pretty much like an MPDU here, its transmission duration should not exceed the TXOP limit. - Felix