ubuntu-7.10 and wireless channel search

[Ed Arnold]

Derek Broughton wrote in response to my post:

> Today's Topics:
> 
>    2. Re: ubuntu-7.10 and wireless channel search (Derek Broughton)
>
> Message: 2
> Date: Wed, 31 Oct 2007 19:49:43 -0300
> From: Derek Broughton <news at pointerstop.ca>
> Subject: Re: ubuntu-7.10 and wireless channel search
> To: ubuntu-users at lists.ubuntu.com
> Message-ID: <3859965.vPNYkcqPLa at cedar.serverforest.com>
> Content-Type: text/plain; charset=us-ascii
> 
> Ed Arnold wrote:
> 
> > I'm a Ubuntu Newbie who just installed Ubuntu 7.10 on a Dell D810
> > laptop, which has a Intel PRO/Wireless 2200BG card.
> > 
> > This machine is dual-boot; the other OS is XP.  When I boot XP, I can
> > change the channel number on my wireless router from 6 to 11, and XP's
> > wireless driver sees the change and does the right thing.  (I really want
> > to change to channel 11, because my neighbors are all crowded together on
> > channel 6.)
> > 
> > When I boot Ubuntu, wireless works fine so long as my wireless router
> > is set to channel 6.
> 
> I'm not sure what you're trying to accomplish - channel selection shouldn't
> even be possible on the client.  You set your router to use a channel, and
> the client adapts.  My router is on channel 11.

Hi,

That's not what I intended to convey; I am setting the channel at the
access point, i.e. the router, and not on the client.  When the channel
is set at 6 (2.437GHz), both Windoze XP and Ubuntu are happy.  When I
reset the channel to 11 (2.462GHz), XP adapts correctly, but the Ubuntu
7.10 driver doesn't.  Why it doesn't is a mystery to me, as it is my
understanding that the receiver in these cards is supposed to
automatically tune itself to the frequency of the strongest signal.
However, I suppose it's possible that these wireless cards are really
dumb devices that don't auto tune, and that the host driver software has
to do the scanning by setting the card's receive frequency and reading
signal strength for each channel 1-14.  Do you know if that is in fact
the way the card's interface works?

> > My question is: how do I find out if the inability of Ubuntu's wireless
> > driver to do channel search, is a problem already known to the Debian/
> > Ubuntu developers?
> 
> I would guess it isn't - because, at least for some of us, that's not a
> problem.
> 
> But now that you mention it, why on earth do both Network Manager and
> iwconfig report your channel as a Frequency?  How difficult could it be to
> map that to the channel set on the router?

Sure, I could change the channel to 11 at the router, then type in
"iwconfig eth1 channel 11" on the client, but that's not how wireless
is supposed to operate.  And, if I were in a building doing a lot of
roaming, I sure wouldn't want to have to be typing iwconfig commands
constantly to try to find a strong signal.  Either firmware on the
wireless card, or software in the host driver, is supposed to
periodically scan the channels for the strongest signal, and either
associate with the strongest, or hand the data to the user and let him
make an association.  Obviously, Windoze XP does this correctly; the
question is, why doesn't Ubuntu do the same thing?