From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from ra.se.axis.com ([195.60.68.13]:44729 "EHLO ra.se.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932175Ab1EYIIK (ORCPT ); Wed, 25 May 2011 04:08:10 -0400 Date: Wed, 25 May 2011 10:08:07 +0200 (CEST) From: Cristian Ionescu-Idbohrn Reply-To: Cristian Ionescu-Idbohrn To: hostap@lists.shmoo.com cc: linux-wireless@vger.kernel.org Subject: Re: Initial automatic channel selection implementation In-Reply-To: <201105250624.32360.helmut.schaa@googlemail.com> Message-ID: <1105251003410.26419@somehost> (sfid-20110525_100816_456387_AD6ABBD2) References: <1105241841310.6936@somehost> <4DDBE538.1090902@gnu.org> <201105250624.32360.helmut.schaa@googlemail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, 25 May 2011, Helmut Schaa wrote: > Am Dienstag, 24. Mai 2011 schrieb Pavel Roskin: > > On 05/24/2011 12:44 PM, Cristian Ionescu-Idbohrn wrote: > > > On Tue, 24 May 2011, Pavel Roskin wrote: > > >> > > >> Speaking of channels, I think only some channels should be eligible for > > >> automatic selection (that would be 1, 6 and 11 in the 2.4 GHz range). > > > > > > May I ask what the rationale behind that may be? > > > > That's a safe distance between channels. That's why channels 1, 6 and > > 11 are used more often than others. > > > > Our algorithm make select, say, channel 3. That may be the most quiet > > channel at the moment. We may use absolutely the best algorithm to > > determine that. However, it is likely that APs operating on channels 1 > > and 6 would eventually appear in vicinity, and out AP would interfere > > with both of them instead of just one of them. > > > > Using a car analogy, consider channels 1, 6 and 11 like lanes on a > > highway. Using other channels would be like driving between lanes. It > > may seem safe, but only in absence of other traffic. > > > > It's possible that the list of autoselectable channels could be country > > specific. I would hate to add complexity to CRDA. Hopefully we could > > device a simple algorithm to find the autoselectable channels based on > > the CRDA data. > > Why not use a channel list as input to the algorithm (in whatever form). > Hence, it would work for all channels (if the user wishes to do so) but it > can be limited to a list of preferred channels (1,6,11). Now, that would be a much smarter way to do it. Remains to decide a similary smart fall back when a preferred channel list is not provided. Cheers, -- Cristian