Return-path: Received: from mail-iw0-f178.google.com ([209.85.223.178]:41138 "EHLO mail-iw0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753197AbZKSAVR (ORCPT ); Wed, 18 Nov 2009 19:21:17 -0500 Received: by iwn8 with SMTP id 8so1339298iwn.33 for ; Wed, 18 Nov 2009 16:21:23 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20091118230506.GA5889@jm.kir.nu> References: <43e72e890911171337p4b0d97fcp844266137bb51b56@mail.gmail.com> <43e72e890911171345q2dc59d66g6ac2a9eec04c577c@mail.gmail.com> <4B031B48.1090105@roinet.com> <43e72e890911171404x1a46d07alb54946768d0f9cf5@mail.gmail.com> <4B032390.3080501@roinet.com> <20091117225408.GA20540@jm.kir.nu> <43e72e890911171512k562f9329td56cc741dd1c5151@mail.gmail.com> <1258581492.10593.24.camel@mj> <43e72e890911181408r43dadf7av277b255eb9007481@mail.gmail.com> <20091118230506.GA5889@jm.kir.nu> From: "Luis R. Rodriguez" Date: Wed, 18 Nov 2009 16:21:03 -0800 Message-ID: <43e72e890911181621g4c2c28e1m693e8bc4796e73e1@mail.gmail.com> Subject: Re: [Madwifi-devel] Survey: What are you using MadWifi for, and why? To: "Luis R. Rodriguez" , Pavel Roskin , David Acker , Andrey Yurovsky , Michael Renzmann , madwifi-devel@lists.sourceforge.net, madwifi-users@lists.sourceforge.net, linux-wireless Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, Nov 18, 2009 at 3:05 PM, Jouni Malinen wrote: > On Wed, Nov 18, 2009 at 02:08:16PM -0800, Luis R. Rodriguez wrote: >> Are you aware of any regulatory rules which prohibit narrower >> channels? It just seems odd. > > I don't remember any rules that would explicitly do that, but there may > be some implicit limitations due to the slower TX rate. I don't know > whether this would hit anywhere, but at least quarter width channel with > 1 Mbps TX rate and maximum frame length might get pretty close to some > maximum TX-without-sensing limits. Though, that is less likely to be an > issue on 5 GHz band due to 6 Mbps minimum TX rate even at quarter > channels could be fast enough. There could also be some rules that state > the minimum TX rate, so there could potentially be need to change > supported rate sets and/or fragmentation threshold in some corner cases. > > Actually, even with 6/4 Mbps TX rate, the channel sensing rule in Japan > (carrier sense every 4 ms) (if that rule is still valid.. haven't > really checked), we could hit the limit with maximum frame length. Thanks for the details, we'll poke our regulatory guys just to confirm. Luis