WLAN Slow on local transfers

[Issac]

Hi, thanks for taking the time to look over this. :)

Something I've been scratching my head at for a while is my wireless network, and how well it works for transferring/streaming local files from one computer to the other.

I have a 802.11n linksys router (Linksys... that could be the problem right there? :p), model is WRT150N. Right now it's set to b/g mixed, though 99% of the time only n/g NICs are connected at any given time. The only reason it's b/g is because sometimes I flip my DS on, which uses b, to play online.

Usually what happens is, the transfer speed caps out at ~800KBps over a local transfer, which is a little sad. The attached picture is an example of such.

Could the b/g mixed have something to do with the issue?
I also understand that encryption can cause problems. I use WEP to secure mine, and would rather not leave my network unprotected. Any suggestions there?
My router is capable of WEP, WPA, WPA2, and Radius.

[JamesO]

Transfer rate is stated in kiloBytes per second. kBps

Data rate is stated in kilobits per second. kbps

To convert from kiloBytes to kilobits, multiply by 8.

Your data rate of the transfer is actually 6.440 Mbps or Megabits per second.

For a wireless LAN this may be as expected depending upon the signal strength.

I would try an internet speed test from each machine to the following sites and see what kind of transfer speeds you get;

http://www.speakeasy.net/speedtest

http://speedtest.net

And see if you have a limiting speed from either of these machines.

Keep in mind the slowest link speed will be the limiting factor of this transfer as well as other factors such as buffers and moving data and preparing it for transfer.

JamesO

[Issac]

I appreciate your response, however I do understand the difference between KB(or kB) and kb.

I'm not concerned about my actual internet connection speed. With lolcomcast I get 6-8mbps with lolpowerboost that doubles it for 10 seconds (OH WOW.)

What I want is to know if it's possible to get at least 24-28 or those 54mbps in wireless g on local transfers. I notice it throttles a lot regardless of the signal strength on all of my computers. The picture above is a local transfer from my desktop to my laptop over my wireless network. 800KB (or kB) is not acceptable for a local network transfer that is supposed to be rated for a max of 54mbps. At the very least I would expect, bare minimum, 15mbps.

There are like 6 other wireless networks around me, all of them with a signal strength of 2/6 bars or less. Would these cause the throttle to be this severe when the signal strength of all my computers to my network is very good?

Thanks for any response.

(By the way, I'm not a big fan of comcast because I work for cablevision, and we have 12-14mbps on the average for most of our subscribers.)

[JamesO]

My understanding is 54 Mbps is the raw maximum one way data rate under ideal circumstances. The best expected data rate is typically 1/2 the max rated speed, again under ideal circumstances. I think about 24 Mbps is the best expected data rate due to FEC, flags, syncs, SSID broadcasts, etc? Also keep in mind TCP/IP requires about 20% overhead, so you will never get the full rated data transfer?

Then you need to factor in many things like interference, signal strength, router performance, etc. It may be possible that router handling 2 wireless sessions needs to then cut the 24 Mbps max rate in half again??

I would experiment with turning off encryption, configuring as wireless G only, and then connecting a single machine via wire and one still wirelessly. Then flip flop the wired and wireless machines to see if anything changes.

I would start by using a cross over cable to internal NIC's then use this as my benchmark. I know in the past I have performed some throughput testing with 100 Mbps Ethernet NIC's and have had to kill many processes on the machines to get close to the rated 100 Mbps throughput. Then in the end, you still have the standard TCP/IP overhead that cuts about 20% into the final figure from what I recall? Other factors like buss speeds, memory transfer, and other background tasks can also cut into max data speeds as well.

You have to be aware of any tasks that may be communicating out to the Internet in the background as well. IM programs, RSS feeds, printer software, Mail clients, A/V programs etc.

I may be wrong about some of this as it has been a long time since I have been deeply involved with some of this to the nitty gritty level. I assume the experts will make corrections where necessary.

JamesO

[johnwill]

Keep in mind that 802.11b/g is also half-duplex, and the SMB protocol has a lot of overhead. Wireless file transfers are usually fairly painful. James is also correct, the best connection speed I've seen with a perfect connection for 802.11b is 28mbits/sec real throughput.