Date: Sat, 02 Apr 2005 13:58:31 -0800 From: Sam Leffler <sam@errno.com> To: Brian Reichert <reichert@numachi.com> Cc: freebsd-hackers@freebsd.org Subject: Re: which Wifi cards can be used for a WAP? Message-ID: <424F1587.8060105@errno.com> In-Reply-To: <20050402171635.GV44514@numachi.com> References: <20050402065052.GT44514@numachi.com> <20050402162842.GU44514@numachi.com> <20050402171635.GV44514@numachi.com>
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Brian Reichert wrote: > On Sat, Apr 02, 2005 at 11:28:42AM -0500, Brian Reichert wrote: > >> I guess everything listed here, with a URL to an up-to-date list: >> >> <http://customerproducts.atheros.com/customerproducts>; > > > In perusing many of these cards specs, I see many of them offer a > 'turbo mode' of 108 Mbps. > > - Is this something magically supported by the hardware? By that, > I mean: if I use a compatible WiFi card in a laptop, they'll just > negotiate the higher rate, and as such the kernel driver has no > impact? Turbo mode is an Atheros-specific thing that bonds two channels to double the effective bandwidth. I know of no other vendor that implements it. There are various techniques for increasing the effective bandwidth of an 802.11 medium; none are standardized (yet). > > - I'm seeing 'turbo 802.11g' vs. 'Super G'. I haven't found any > thing that tells me if these are synonyms, or if they are > incompatable unofficial extansions of a spec. Does anyone here > know? > SuperG is a label for a number of different features that are implemented as Atheros-specific protocol extensions. Other vendors can implement most of them (Atheros has released the details of these extensions) but it's unlikely you'll find many vendors picking them up. I have code that implements most of SuperG (only compression is missing) but haven't committed any of these yet (not sure when I'll do this and/or if all warrant going in FreeBSD). Turbo 11g is the use of Atheros Turbo mode in the 2.4GHz band. This is only possible on channel 6 as you need to bond two channels and is permitted only when non-Turbo-capable stations are detected. Consequently it's really only useful in the 2.4 band in a private environment. OTOH you can operate in 11a (5GHz) with more freedom and SuperG can easily get you transfer rates upwards of 60 Mb/s. Sam
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