Date: Thu, 26 Mar 2009 11:12:41 +0100 From: "Paul B. Mahol" <onemda@gmail.com> To: yuri@rawbw.com Cc: freebsd-hackers@freebsd.org Subject: Re: Atheros wireless card keeps losing signal when signal is too weak Message-ID: <3a142e750903260312k20e34aafn49b6445c9c955adf@mail.gmail.com> In-Reply-To: <49CB057E.8080900@rawbw.com> References: <49CA7D47.7070406@rawbw.com> <3a142e750903251350l66801af4j26722a5b905a9a34@mail.gmail.com> <49CAA27A.6060602@freebsd.org> <49CB057E.8080900@rawbw.com>
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On 3/26/09, Yuri <yuri@rawbw.com> wrote: > Sam Leffler wrote: >> 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. >> > > I did identify my FreeBSD version and card in my original post, but here > they are again: > 7.1-STABLE > ath_hal: 0.9.20.3 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413, RF5413) > ath0: <Atheros 5212> mem 0xcffe0000-0xcffeffff irq 16 at device 5.0 on pci0 > > One way or another little cheap laptop card with ndis driver delivers > more steady connection then atheros pci card connected to freebsd. > Maybe like you mentioned Linux has higher tolerance to missing beacons. > Does it make sense to have a parameter "lost beakon tolerance"? Perhaps this is what are you looking for: bmissthreshold count Set the number of consecutive missed beacons at which the station will attempt to roam (i.e., search for a new access point). The count parameter must be in the range 1 to 255; though the upper bound may be reduced according to device capabilities. The default threshold is 7 consecutive missed beacons; but this may be overridden by the device driver. Another name for the bmissthreshold parameter is bmiss. -- Paul
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