Wireless considerably faster one way than the other

Dave Brown · 2006-06-15T20:35:06+00:00

Acer Travelmate laptop with built-in Intel 2200GB 802.11b/g wirelessnetwork adaptor, XP Pro.Netgear ME102 802.11b Access Point, plugged into network hub.2 more desktop machines plugged into the hub, both Win 2k, it's a 100Mbnetwork.The Access Point is approximately 3 inches away from the laptop.I'm experiencing really bad network throughput at the laptop end, buthave discovered that copying a large file from the laptop to one of thedesktop machines is fast - the problem seems to be only whentransmitting data TO the laptop. I get all sorts of network errors,including disconnections. Signal strength on the laptop is a full setof green bars when I look at the connection status, "excellent" when Ihover over the tray icon.I downloaded QCheck, installed it on a desktop machine and the laptop.When I run a throughput test at the laptop, sending from the laptop toa desktop machine with 100kb packet size, I get roughly 5 to 6 Mbps,which as I understand is as good as you can expect from 802.11b.However, when I run the test from a desktop machine to the laptop, Iget around 30 kbps. Yep, kilobytes per second. And that's when itworks, most of the time the test fails - it only works reliably when Ireduce the packet size down to, say 5kb, then it shows a throughput ofabout 1 Mbps.Anyone have any idea what could be causing this? I've tried allpossible channel settings, and combinations of all other settings I cansee.

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Dave Brown 20 years ago

Hey, you're not going to believe this...

So I bought myself a nice shiny new 11g access point, nice unit, 3Com OfficeConnect ADSL, 11g & Router.

Hmm. QCheck now shows that my throughput is roughly 500k to 1Mbps in both directions. The Intel statistics show that there's around 75% transmit errors. I've played with all the settings I can imagine, to no avail. This is slower than I was originally getting when checking throughput from laptop to desktop when I was using the old (broken?)

11b access point.

Fortunately the access point came with a free USB 11g network adaptor stick. I plug that in instead of using the laptops built-in Intel

2200bg adapter, and bingo, my throughput goes to roughly 15-20 Mbps. I can't see the Intel statistics on this because the Intel software won't recognise it.

Huh?

Dave

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Dave Brown 20 years ago

Ok, so I had a revelation while walking the dog. I wonder what will happen if, as has been pointed out several times to me (he said in an embarrassed tone of voice), I move the laptop further away from the access point.

Yeah, well now I'm getting 10-15 Mbps.

Hardware..... it's a mystery to me. I used to understand it once.

Dave

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Jeff Liebermann 20 years ago

"Dave Brown" hath wroth:

Be sure to thank the dog. I've often worked on a problem for literally days without any results. I eventually press the mental reset button and blunder off to do something else. That's when the divine inspiration or cosmic revelation arrives with the answer.

Message-ID:

RF is mostly magic. Nobody really understands magic.

I'm curious how far away you have to be in order to keep the error rate down. It would be a nice addition to the FAQ.

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John Navas 20 years ago

On Wed, 21 Jun 2006 22:24:00 -0700, Jeff Liebermann wrote in :

The three laws of prediction (particularly #3):

When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
Any sufficiently advanced technology is indistinguishable from magic.

-Arthur C. Clarke

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Jeff Liebermann 20 years ago

John Navas hath wroth:

My version:

Assumption, the mother of all screwups.

That which is most obviously correct, beyond any need of verification, and which has been ossified into established dogma, is probably wrong[1].
Only those that are unfamiliar with the limits of knowledge, are able to transcend them. In other words, real progress is usually done by the ignorant.

Any sufficiently advanced communications technology is indistinguishable from noise.
Most amazing discoveries are accidental and a side effect or diversion from attempting something else. These discoveries go to the most observant, not the most knowledgeable.

Computers make simple things simpler, complex things more complex, tedious things about the same, and beautify the output of all of these.
Experience is the knowledge of what rules can be broken without blowing up the lab.

Communications protocols that resemble legal documents were probably written by attorneys, not engineers.
Intuitive user interfaces, the come with an instruction manual, are not intuitive.

Indecision is the key to flexibility.

[1] I'm currently reading "The Sources of Europe's Mild Climate" in the current American Scientist magazine, which debunks the common assumption that the Gulf Stream is what keeps Europe's climate warm.

formatting link

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Dave Brown 20 years ago

Believe me, he's very useful. I've lost count of the number of times I've been stuck on some code, then resolved the problem during a dog walk. Always carry a voice recorder with me for that very reason. Along with a collection of poo-bags.

I'll run some tests. What was also interesting was that the USB stick performed admirably when the AP was close (about 3 feet).

Dave

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