From owner-freebsd-hackers@FreeBSD.ORG Wed Mar 25 21:30:36 2009 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2E9DC1065736 for ; Wed, 25 Mar 2009 21:30:36 +0000 (UTC) (envelope-from sam@freebsd.org) Received: from ebb.errno.com (ebb.errno.com [69.12.149.25]) by mx1.freebsd.org (Postfix) with ESMTP id EC9688FC20 for ; Wed, 25 Mar 2009 21:30:35 +0000 (UTC) (envelope-from sam@freebsd.org) Received: from trouble.errno.com (trouble.errno.com [10.0.0.248]) (authenticated bits=0) by ebb.errno.com (8.13.6/8.12.6) with ESMTP id n2PLUYtZ047292 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 25 Mar 2009 14:30:35 -0700 (PDT) (envelope-from sam@freebsd.org) Message-ID: <49CAA27A.6060602@freebsd.org> Date: Wed, 25 Mar 2009 14:30:34 -0700 From: Sam Leffler Organization: FreeBSD Project User-Agent: Thunderbird 2.0.0.18 (X11/20081209) MIME-Version: 1.0 To: "Paul B. Mahol" References: <49CA7D47.7070406@rawbw.com> <3a142e750903251350l66801af4j26722a5b905a9a34@mail.gmail.com> In-Reply-To: <3a142e750903251350l66801af4j26722a5b905a9a34@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-DCC-sonic.net-Metrics: ebb.errno.com; whitelist Cc: yuri@rawbw.com, freebsd-hackers@freebsd.org Subject: Re: Atheros wireless card keeps losing signal when signal is too weak X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 25 Mar 2009 21:30:38 -0000 Paul B. Mahol wrote: > On 3/25/09, Yuri wrote: > >> I have Linux box sitting next to FreeBSD box that has a very cheap >> Airlink 101 card but it has no problems connecting to my WiFi network. >> >> Every time when Linux box says that quality of connection drops below >> 10/100 FreeBSD box shows "status: no carrier". >> Linux connections still function ok. >> >> I even bought a large WiFi antenna for FreeBSD box but still have this >> problem. >> >> Is there some 'sensitivity' parameter that driver may be setting too low >> on the card? >> > > I'm only aware of roam:rssi & roam:rate > > Those parameters control the roaming algorithm. The OP didn't identify their card, freebsd version, or provide any info about their setup or why ifconfig reports "no carrier". It just sounds like there's a loss in the signal and freebsd gets a beacon miss and tries to reconnect while linux does not. Once the rssi drops to "10" (presumably 5dBm) minor variations in the environment can become significant (e.g. orientation of a laptop, obstructions, antenna quality) and it's impossible to comment on what's happening w/o detailed information such as provided by athstats. FWIW cardbus cards that follow the reference design closely typically work pretty well and don't benefit from an external antenna. Vendors of cheap designs often scrimp when it comes to the antenna. When wireless is inside a case (e.g. a PCI card) then it's worth remoting the antenna but you need to be careful about routing the pigtail(s) and I can't count the number of times I've tracked problems down to faulty cables and/or connections. Sam