Return-path: Received: from mail-bw0-f46.google.com ([209.85.214.46]:52480 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750966Ab1EYE03 (ORCPT ); Wed, 25 May 2011 00:26:29 -0400 Received: by bwz15 with SMTP id 15so6201949bwz.19 for ; Tue, 24 May 2011 21:26:28 -0700 (PDT) From: Helmut Schaa To: Pavel Roskin Subject: Re: Initial automatic channel selection implementation Date: Wed, 25 May 2011 06:24:32 +0200 Cc: "Cristian Ionescu-Idbohrn" , hostap@lists.shmoo.com, linux-wireless@vger.kernel.org References: <1105241841310.6936@somehost> <4DDBE538.1090902@gnu.org> In-Reply-To: <4DDBE538.1090902@gnu.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Message-Id: <201105250624.32360.helmut.schaa@googlemail.com> (sfid-20110525_062636_652356_CDB0D36B) Sender: linux-wireless-owner@vger.kernel.org List-ID: 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). Helmut