Slow performance over wireless LAN

[mbaxter22]

I have an 802.11b wireless LAN setup at home. There are three computers, all equipped with PCMCIA wireless LAN cards. The DSL connection goes into a Dell RG-1000 Residential Gateway, which acts as a router for the DSL connection, but also as a DHCP server and hub for all the client machines.

The client machines all get an IP address assigned just like they should when I bootup, and they all share the DSL connection just fine. No performance issues there (my DSL never gets more than about 1Mbps so there's no possibility of the 11Mbps bandwidth getting saturated by the DSL).

My complaint is with regards to communication between the computers on my home network. I have done a number of tests, timing file transfers between my three machines. No matter what machine I transfer a file from, I never get more than 1.9Mbps effective data rate.

For example:

-Copying files from Desktop PC to Inspiron 8100 laptop:

49 seconds to copy 10.9MB (222kbytes/sec = ~1.78Mbps)
76 seconds to copy 14.1MB (186kbytes/sec = ~1.48Mbps)

-Copying files from Desktop PC to Compaq LTE 5300 laptop:

61 seconds to copy 14.1MB (230kbytes/sec = ~1.84Mbps)
54 seconds to copy 11.9MB (220kbytes/sec = ~1.76Mbps)

-Copying files from LTE5300 to I8100 (using peer to peer "Ad-Hoc" mode, with the Desktop PC and RG-1000 router turned off):
79 seconds to copy 18.7MB (237kbytes/sec = ~1.89Mbps)
36 seconds to copy 8.4MB (233kbytes/sec = ~1.87Mbps)


Notice that I get crappy transfer rates no matter what method I use to wirelessly connect the machines together (wireless hub or peer-to-peer, makes no difference). By the way, just for the record I unplugged my cordless phone while doing these tests, just to be sure. I also did some tests with the phone plugged in. Didn't make any difference.

The problem is something else. Any thoughts? Could the fact that I'm using PCMCIA cards have anything to do with it? What's the max data transfer rate of a PC Card anyway? Or maybe something else I should look into?

thanks

 

[spidey07]

depending on signal strength and quality wireless will use 11, 5.5, 2, and 1 Mbs I believe. could be too much interference? I've seen a lot of cards just drop down to 1 Mbs with as little as a wall in the way.

 

[cchan]

Are you using WEP? On some cards, turning on WEP will kill your throughput. And like you said, your numbers are *effective* throughput, which is always a lot lower than theoretical bandwidth.

 

[ktwebb]

In a perfect environment, one with nodes in the same room as the AP and no interference you should get anywhere from 4.5 to 6.5 megabit per second throughput depending on your wireless hardware. One thing that I thought about was your slower spindle HDD's in the laptops but even that wouldnt account for that much drop off. Enabled WEP will hurt ya, but only a megabit at worst. Have you played around with the position of the AP's and/or antennas. Are there two antennas or only one and if there are two, is diversity turned on? Is your firmware current. What about a feature set on the AP. Is there a setting for Throughput or range? How about the firmware and drivers for your client cards? Current?

 

[mbaxter22]

<< In a perfect environment, one with nodes in the same room as the AP and no interference you should get anywhere from 4.5 to 6.5 megabit per second throughput depending on your wireless hardware. One thing that I thought about was your slower spindle HDD's in the laptops but even that wouldnt account for that much drop off. Enabled WEP will hurt ya, but only a megabit at worst. Have you played around with the position of the AP's and/or antennas. Are there two antennas or only one and if there are two, is diversity turned on? Is your firmware current. What about a feature set on the AP. Is there a setting for Throughput or range? How about the firmware and drivers for your client cards? Current? >>



I've tried it with no encryption key, and it didn't help. As far as interference goes, that's definitely not the problem. I've even tried file transfers in peer-to-peer mode between the Dell laptop and the PC with the two machines less than a foot apart. The diagnostic software always shows signal strength as "Very Good" or "Excellent", btw.

Also, I should mention that the cards and the AP have the most recent firmware available, and the cards are all using up-to-date drivers. Just don't know what to make of it. I wish I could compare performance with someone else's wireless network.

Well I'll definitely let you guys know if I find out what the deal is.