Is the tray icon tool accurate? If so, why does the connection speed
slow down?
Thanks.
I can tell you my experience : I had the same problem, and after a
couple of days of scratching my head, I discovered a school close to me
has a wireless lan broadcasting on the same channel 1
I suppose they have installed an outdoor antenna, to reach all the
rooms. Altough I'm not able to spot it.
My suggestion is to change from the default channel(1) to another one.
This is normal response to interference and reflections. How much
speed juggling it does is dependent on the algorithm used. The way it
works is that the client tries to associate with the access point at
the highest speed possible. This is advertised in the management
frames so there's no trial and error involved like in dialup modems.
It usually succeeds making the initial connection at the highest speed
because there's very little traffic moving and the probability of a
successful association is rather high.
That usually remains the situation until you start moving data. At
54Mbits/sec association speed, anything furthur than about 8ft range
(using typical antennas) is going to create data errors. The data
arrives corrupted by noise. The access point detect the arrival of
corrupted packets and lowers the speed in order to reduce the error
rate to reasonable level. Depending on range, it will reduce the
speed until it gets a decent error rate (about 1 error in 10^5 bits).
However, that how it should work without any interference present.
With interference, there's a problem. The speed can go down to the
very slowest speed (1Mbit/sec) and there will still be errors. In
fact, since the same size packets take longer to transmit at the
slower speeds, the probability of a packet getting trashed by
interference is even higher with slower speeds. Having the speed
plunge to 1Mbit/sec is a sure sign of local interference.
A good question is how does this system recover from an interference
hit? In other words, what criteria or algorithm determines when it
should increase in speed again. I had illusions that some
sophistocated statistical algorithm was employed. Nope. One AP
product used a simple timer. After 10 seconds of no traffic, it would
reset the speed back to the maximum speed and just start over. I
suspect most are like this. Cheap, crude, functional, but not very
elegant or optimal.
--
Jeff Liebermann je...@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
http://forum.notebookreview.com/showthread.php?t=11402&page=1&pp=10
DS
<shepar...@yahoo.com> wrote in message
news:1121496218....@g47g2000cwa.googlegroups.com...
I just read through all 233 articles in that blog. Methinks almost
everyone is ignoring a common issue. The few that bothered to post
details on their hardware indicated that they were using Linksys
WRT54G access points. Much of the rest is consists of trial an error
testing of various drivers with very inconsistent results. Are you
prehaps using a Linksys router?
What everyone seemed to be ignoring is that it's the access point, and
not the Intel Centrino client, that sets the speed. Centrino simply
follows the speed that the access point commands. If the forum users
had tried to set the speed of the access point to some reasonable
speed (i.e. about 12 or 24Mbit/sec), instead of "auto", they would
probably have found that their connection was stable. It would be an
interesting test.
My guess(tm) is that Intel's driver isn't returning some management
request in time for the access point to respond. This is not the
first time this has happened with the Philips Centrino chipset. When
the Netgear MR814v1 was new in early 2004, when the Centrino chipset
started to appear in OEM laptops, the two devices would connect and
drop repeatedly. I never did find out exactly which company screwed
up, but Netgear was forced to loosen their timing specs to accomidate
Centrino. (Biggest company always wins). I'm guessing this is more
of the same.
I don't have a fix. Try the various Intel drivers and see what
happens. If that doesn't work, try setting the access point to a
fixed but reasonable speed and see if that helps.
I guess I will just live with it for now and hope that a certain fix is
put out soon by Intel. Amazing that it has persisted this long. I
called a few acquaintances with this same wireless setup and they all
confirmed they had the same thing happening. I try to use an ethernet
connection when downloading updates and programs so the wireless card
does not affect that. Browsing sometimes slows to the point of
dropping the connection, but almost immediately reconnects at a higher
speed.
Jeff Liebermann wrote:
> I just read through all 233 articles in that blog. Methinks almost
> everyone is ignoring a common issue. The few that bothered to post
> details on their hardware indicated that they were using Linksys
> WRT54G access points. Much of the rest is consists of trial an error
> testing of various drivers with very inconsistent results. Are you
> prehaps using a Linksys router?
>
>