1. Home
  2. Wireless Networking
  3. Wireless considerably faster one way than the other

Wireless considerably faster one way than the other

Acer Travelmate laptop with built-in Intel 2200GB 802.11b/g wireless network 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 100Mb network. The Access Point is approximately 3 inches away from the laptop.

I'm experiencing really bad network throughput at the laptop end, but have discovered that copying a large file from the laptop to one of the desktop machines is fast - the problem seems to be only when transmitting data TO the laptop. I get all sorts of network errors, including disconnections. Signal strength on the laptop is a full set of green bars when I look at the connection status, "excellent" when I hover 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 to a 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, I get around 30 kbps. Yep, kilobytes per second. And that's when it works, most of the time the test fails - it only works reliably when I reduce the packet size down to, say 5kb, then it shows a throughput of about 1 Mbps.

Anyone have any idea what could be causing this? I've tried all possible channel settings, and combinations of all other settings I can see.

Reply to
Dave Brown
Loading thread data ...

On 15 Jun 2006 13:35:06 -0700, "Dave Brown" wrote in :

That close may result in signal overloading in the radios.

Reply to
John Navas

No, the reason it's that close is because I wanted to rule out distance as a factor. They were originally about 30 feet apart.

Reply to
Dave Brown

On 16 Jun 2006 03:22:49 -0700, "Dave Brown" wrote in :

3" is too close.
Reply to
John Navas

Thanks John, but I'm getting the same results regardless of the distance.

Regards, Dave

Reply to
Dave Brown

On 15 Jun 2006 13:35:06 -0700, "Dave Brown" wrote in :

  1. Restore all settings to default values.
  2. Don't use huge packets, which increases the cost of errors.
  3. Make sure the ME102 has the latest firmware.
  4. Use the latest Intel reference drivers and software for the 2200BG.
  5. Move the wireless units at least a few feet apart.
  6. Try testing with: (a) Iperf . (b) Netio
  7. Check the Intel statistics after transmissions.
Reply to
John Navas

"Dave Brown" hath wroth:

Is the ME102 running the Netgear firmware, or has someone installed firmware from a DWL-900AP+ or WAP11?

Too close. The receivers will overload at that distance. There are also some timing problems that appear at such a short distance. I'm not sure if there's a real minimum distance, but methinks about 12" or more is safe.

Yep, been there. I've seen this when the 10baseT-HDX (half duplex) interface on the access point ends up with a different protocol than your network hub or switch. In particular, with a 10/100 hub or one of the Netgear FS-xxx series 10/100baseT switches. This does not cause disconnects, so that's probably not the problem.

If you're using a 10/100 hub (not switch), I would certainly want to try using a 10baseT only hub, or a 10/100baseT switch, as the buffers in the dual speed hubs are always a problem. Going from 10 -> 100 is not a problem because the buffer can be emptied faster than the 10 port can fill it. However, going from 100 to 10 requires that flow control and buffering work overtime. That's the way you get assymetrical performance.

Maximum theoretical speed at 10Mbits/sec is 7.1Mbits/sec for UDP and

5.9Mbits/sec TCP. Most benchmark tests use file transfers which are TCP. You're going as fast as 802.11b will go.

Fine. Take the other potential sources of error out of the picture. Plug the desktop machine directly into the ME102 access point and try again. You might need a crossover ethernet cable.

Reply to
Jeff Liebermann

Wow, thanks John & Jeff, I've obviously got a few things to try out there. I'll keep you posted, but thanks again in the meantime.

Regards,

Dave

Reply to
Dave Brown

"Dave Brown" wrote in news: snipped-for-privacy@f6g2000cwb.googlegroups.com:

Really stupid question.....what about a wired connection on this laptop ? What speeds do you see from that ?

(Unless there isn't a wired connection of course.)

Reply to
DanS

No, that's a perfectly acceptable question, unfortunately the answer is

93Mbs in both directions. :(

Regarding the other issues that Jeff & John brought up:

Original Netgear firmware. There is an update available, but it doesn't mention anything critical as far as I can see. I'm, a bit reluctant to change it because a) I've seen a number of postings about these AP's being killed by upgrading firmware and b) I've had this AP for about 4 years, and it used to work find with a different laptop/PCMCIA card. Yeah, I've just thought, I might dig out that old card and see if that fixes things - update see end of message.

No change :(

No change.

Using Windows networking, how can I change the packet size?

See answer above.

Got to try that one yet.

No Change.

With desktop as server:

------------------------------------------------------------ Server listening on TCP port 5001 TCP window size: 8.00 KByte (default)

------------------------------------------------------------ [820] local 192.168.0.1 port 5001 connected with 192.168.0.3 port 1555 [ ID] Interval Transfer Bandwidth [820] 0.0-10.0 sec 3.82 MBytes 3.21 Mbits/sec

With laptop as server::

------------------------------------------------------------ Client connecting to 192.168.0.3, TCP port 5001 TCP window size: 8.00 KByte (default)

------------------------------------------------------------ [884] local 192.168.0.1 port 3320 connected with 192.168.0.3 port 5001 read on server close failed: Software caused connection abort [ ID] Interval Transfer Bandwidth [884] 0.0-87.2 sec 48.0 KBytes 4.51 Kbits/sec

I ran this in server mode on the desktop, client on the laptop. I tried it first with a wired connection, fine, I see the client both sends and receives, giving throughput for both. Then I tried in wireless mode. The laptop did a 1k block size transmission, 384 kbyte/sec, then simply hung up on reception, it never did anything else, even though the server end said it had sent.

Is this to do with the reference drivers you mentioned?

Update: I found my old PCMCIA card, and it produces practically identical figures on all tests. So that discounts the laptops built-in network adaptor.

I've not really much idea about how wireless networks work, (I'm a software guy, always blame the hardware), but presumably each end has a transmitter and a receiver. I'm now guessing that the transmitter on the AP is bad. Is that feasible?

Thanks for all your input so far, by the way,

Regards,

Dave

Reply to
Dave Brown

Thanks for trying so many things -- that's very helpful, and serves to eliminate possible problems.

On 17 Jun 2006 05:49:31 -0700, "Dave Brown" wrote in :

Nonetheless, it is still important to upgrade the firmware, which you should be able to do safely -- just get the firmware directly from the manf website and follow instructions carefully. In general, upgrade firmware over a wired (not wireless) connection. Download from

That can sometimes (not always) be done in the driver for the wireless adapter. But since you apparently haven't messed with it, that's probably not a problem.

Might not help, but definitely worth trying. Be sure to uninstall the old drivers and software before installing. Download from

Interesting. Did you abort that manually?

Also interesting.

That's in the Intel connection manager that installs at the same time as the drivers. The statistics (which show the speed profile for all packets as well as errors) should tell us a lot about what's actually going on.

Yep. Really pointing to the ME102. Can you borrow a temporary replacement? If not, please do at least update the firmware.

Yes, although both transmitting and receiving are involved (asymmetrically) in any transfer: Computer A Computer B data block 1 ->

data block 2 ->

Thanks for all your input so far, by the way,

You're a pleasure to work with, and very welcome.

Reply to
John Navas

Hi John,

Upgraded firmware. No change...

No. This is what I've been seeing. If I try to send a large file (and by large, I mean >10k!) to the laptop using Explorer, it just hangs and hangs, then Windows reports that the network name is no longer available. Here, it just says connection abort. Note the interval in that printout - 87 seconds, whereas normally it runs for 10 seconds. Trying a copy from a command prompt, I get "error performing inpage operation", or "the semaphore timeout period has expired". Very small files do go over, and in fact I can - slowly - use the internet through it, presumably because small packets are involved.

Nope, on my own here.

Re the Intel drivers, I downloaded them (80 Mb?????!!!!!) and have them installed. Hasn't made any difference to the throughput - no better, no worse. Signal strength and quality both "excellent". I installed everything from the package, and now have wireless management under Intel control, rather than Windows. I'm looking at the advanced statistics. I tried to copy a 6 Mb file from (success) then to (failure) the laptop. Rather than typing it all out, I did some screen grabs here:

formatting link
Obviously the transmission stats show the full 6Mb, while the reception shows it only got 300k and is using the lower rates more, but apart from that I can't see anything bad. Any ideas?

Regards,

Dave

Reply to
Dave Brown

Whoops, that second link should be

formatting link
.....

Dave

Reply to
Dave Brown

On 17 Jun 2006 08:36:14 -0700, "Dave Brown" wrote in :

No local dealer that accepts returns? You may need to replace the ME102 in any event.

I know, I know. [sigh]

Lots of errors, which is what's presumably causing the speed fallback. I'd think seriously about replacing the ME102, which is pretty ancient in any event.

Reply to
John Navas

Ah well, I had this feeling it would come to this. I suppose it gives me an excuse to go to 802.11g anyway...

Thanks again, I really appreciate your help.

Dave

Reply to
Dave Brown

What about taking the laptop to a nearby WiFi hotspot? Starbucks has a free day pass.

Reply to
dold

Nice idea, but I'm nowhere near one. Actually one of my neighbours has a wifi connection, I can see it. I just don't know who it is!

Reply to
Dave Brown

On Sat, 17 Jun 2006 16:03:14 +0000 (UTC), snipped-for-privacy@XReXXWirel.usenet.us.com wrote in :

Free day pass?! All of them, or just some?

Reply to
John Navas

formatting link
says it expires in 2004, but I think I used mine after that. The page is still there... odd.

Reply to
dold

The opening page says 2004, but if you "sign up now" at the bottom of the page, the next page says "Offer expires January 31, 2007".

Reply to
dold

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.