[mythtv-users] OT: wireless 802.11g pci suggestions

David Wood obsidian at panix.com
Sat Jun 26 21:12:29 EDT 2004


On Sat, 2004-06-26 at 16:30, Myth wrote:
> Anybody have suggestions on a good cheap PCI wireless card for my remote 
> frontend?
> I am running FC1, and have a Netgear WGT624 AP. Can anything use the 
> 'turbo' mode in linux?

I've been down this road, and before I start, I want to warn you. I'm
unhappy with 802.11g in general, and frankly I don't recommend using it
unless running cable is really, really onerous or outright impossible.
Wireless is expensive, finicky, annoying, slow, and prone to constant,
aggravating trouble. 

That said, here are my experiences. I'm sorry it's a bit OT, although I
suspect I will not be the only one preparing to do a PVR on a wireless
network, so I hope it will be helpful to others.

I have a home where running cabling _is_ a major problem. It could be
done, but it would be ugly and very difficult. Wireless was an obvious
alternative, but I needed something that could move multimedia -
especially big video files - without taking hours. That meant bleeding
edge 802.11g wireless hardware, namely "turbo mode" in its various
forms. I also wanted real, functioning encryption, which means WPA
instead of WEP. Not crazy enough yet? I also need it to run in Linux. 

The bad news is, there is currently no Linux support for any "turbo"
802.11g solution. In fact, there is very little Linux support for _any_
802.11g solution. This stems in part from the stunning, ongoing apathy
of the network vendors, the complexity of modern wireless drivers and 
hardware, and FCC regulations that may mean writing open-source drivers
for these cards is actually illegal...

The (somewhat) good news is, there are fairly impressive "wrapper"
solutions for using Windows NDIS drivers in Linux.

http://www.linuxant.com/driverloader/
http://ndiswrapper.sourceforge.net/

Driverloader is commercial, but costs only $20. It's what I use.
NDISWrapper is free. I have not tried it. 

In studying what's out right now, if you want high bandwidth and
advanced security it seems to come down to Linksys and D-Link. In all
cases, high-speed wireless products are backwards compatible with G and
B (optionally, at the cost of speed), but incompatible with other
vendors, so you are going to get locked into a brand. 

Linksys actually uses Linux in their router, and their solution gets a
lot of press. This is a big deal - because (as I found out) router
firmware can be awful (constant reboots, terrible performance, even
out-and-out broken), and the vendor will simply refuse to fix it. A
Linux-based router where you can fix your own problems means their
router is likely to win on features and reliability hands down.
Amazingly, despite this, Linksys doesn't support Linux drivers for their
client cards. Well, who does. They do support WPA and "turbo G" based on
a new Broadcom chipset. They're more cautious (or honest) about the
benefits - they claim 30-40% improvement on G's 54Mb. 

D-Link, however, seemed to win in reviews on both speed and (most
important to me) signal strength. Their turbo mode involves channel
bonding among other optimizations and is marketed as a "108Mb" solution.
The rumor is that this system disrupts neighboring networks, but I don't
know if that's been firmly established. In a way the whole concept is
laughable. 2.4Ghz is the wild west. Everything interferes with
everything else... Microwaves, telephones, flourescent lights, you name
it. 
 
I took the plunge and got a D-Link. $80 router, $50 PCI cards. My life
has not been easy since. But, I am using it (108Mb, WPA encryption) as I
write, and although my problems with it are far from solved, it is
usable - for the most part. 

First, aside from anything to do with Linux, 802.11G (let alone turbo)
is not all its cracked up to be. I had terrible problems with signal
strength just using Windows clients. I couldn't go 30 feet, through just
two walls. Metal in the walls? Cosmic rays? Interference from
neighboring LANs? Who knows. But buyer beware. After reading on the
internet, it's clear I wasn't the only one to be shocked at how weak
802.11 signals really are. I tried expensive 3rd party antennas, and was
terribly disappointed (this barely made a difference). In the end, I
spent days carefully repositioning everything to finally establish
mediocre signal strength to all clients. 

I read many horror stories about constant router reboots with D-Link.
With current firmware I didn't have that problem, though I have a
different one; after running for between 8-12 hours, performance will
degrade to the point where a DNS lookup will take 30 seconds. The
workaround? Reboot the router every 8-12 hours (or more often, to
taste). Ugly ugly ugly. Will D-Link ever fix their firmware? Hah. Hold
your breath and wait.

Driverloader has a mailing list and good (although not perfect) tech
support compared to most small software vendors. So I don't feel
cheated. But I went through the wringer with Kernel OOPSes and terrible
performance. A combination of kernel upgrades and configs and new
versions of the wrapper have me stable and I can usually get equivalent
speed to what I see in Windows... in other words, mediocre. I see about
1MB (megabyte/sec) transfer rates, and often see this sag lower. All a
function of the weak 802.11 signals. I should see 2-3 times that.

I didn't mention the fun part. My linux client just loses the network
every few hours. Only shutting down the network, removing the
driverloader module, and reloading it will get me back up. I wrote a
shell script to check the results of ping and do this restart if the
ping fails. It runs every five minutes. Fun, right? Welcome to my world.

I am tempted just to try the Linksys hardware as an alternative and
return it if it isn't an improvement, but at this point I'm cynical and
exhausted with the whole mess. It's tough to justify the trouble, given
that from what I've read, compared to D-Link, Linksys is the "weak
signal" brand. But who knows. I may still give it a try. 

So what does it all add up to? You can get 108MB+WPA wireless on Linux.
But you probably don't want to. At least not yet.



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