Return-path: Received: from mail.candelatech.com ([208.74.158.172]:55416 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753573Ab1BFTye (ORCPT ); Sun, 6 Feb 2011 14:54:34 -0500 Message-ID: <4D4EFC76.6090000@candelatech.com> Date: Sun, 06 Feb 2011 11:54:30 -0800 From: Ben Greear MIME-Version: 1.0 To: Felix Fietkau CC: "linux-wireless@vger.kernel.org" Subject: Re: Scanning and channel types. References: <4D4EF004.3040109@candelatech.com> <4D4EF99D.5020601@openwrt.org> In-Reply-To: <4D4EF99D.5020601@openwrt.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 02/06/2011 11:42 AM, Felix Fietkau wrote: > On 2011-02-06 8:01 PM, Ben Greear wrote: >> Current code always sets the channel type to NO_HT when scanning. >> >> From what I can tell, we should be able to send NO_HT packets on >> any channel type, and for passive scanning, it should not matter >> at all what channel-type we are using. >> >> I tested relaxing scanning to use the current channel type >> when scanning on the operating channel, and it seems to >> work. >> >> Does anyone see any problems with this approach? > One thing you should make sure is that once you're done associating to > an NO_HT or HT20 AP (and you have no other interfaces to consider), the > channel mode must not be HT40 - otherwise it could reduce throughput. That is currently handled correctly by the ieee80211_set_channel_type method, as far as I can tell... Regardless of that, in my multi-vif testing, I see lower throughput when using HT40- than using HT20 (between 128 ath9k vif machine and 1 VAP ath9k machine). The VIFS all claim 300Mbps rate. I haven't looked into this any further at this point... Thanks, Ben > > - Felix -- Ben Greear Candela Technologies Inc http://www.candelatech.com