up vote 1 down vote favorite
2
share [g+] share [fb]

I have a Netgear DG834G ADSL modem/802.11g router at home. My notebook and media centre PC (both (K)ubuntu 10.04) both connect at a reported speed of 54 Mbit/s, yet copying files between the two gives an average transfer speed of around 9Mbps. I see the same speed whether I use scp, FTP or even just iperf.

I tried copying something from my wife's notebook (Windows 7) to the media center and to my notebook using scp, both of which give me an average speed of around 6 Mbit/s.

On all three machines the wireless is reporting a link speed of 54 Mbit/s most of the time, sometimes it drops to 48 Mbit/s. All three machines and the Netgear router are within 4 metres of each other with no walls between any of them.

Based on tops I've found on other sites while researching this, I have tried changing the channel used on the wireless router to 1 and 6 (default was 11) and it makes no difference. I even tried to force the router to use 802.11g only, which also makes no difference.

I understand that the throughput won't ever reach 54 Mbit/s, but surely it should be significantly more than what I'm currently able to achieve.

Am I missing something obvious?

link|improve this question
75% accept rate
I have similar performance when transferring data from one wirelessly connected computer to another. For me it works much faster when I transfer data from wired to wireless PC or other way around. – AndrejaKo Jul 27 '10 at 9:54
Are your measurements M*b*ps or M*B*ps? It's a critical difference. – Fake Name Jul 27 '10 at 11:38
Read the first paragraph of my question. Its pretty clear, and since the entire question uses the same measurement, it's also pretty irrelevant. – Graeme Donaldson Jul 27 '10 at 14:25
feedback

4 Answers

up vote 1 down vote

Don't forget that there's a lot of encryption and protocol overhead when the clients talk to the access points.

My experience: On a 54 MBit WLAN you'll reach about 2 MB/s (Megabyte/s) if your connection is really good and there are not to many other clients and networks around.

link|improve this answer
2 MB/s is my experience as well. That said, the asker is getting roughly half that via iperf. That's not good. – afrazier Dec 16 '10 at 20:11
feedback
up vote 1 down vote

They are sharing the same channel. From what I know so far (not much) you are sharing the 54 Mbit/s between devices. So you are actually transferring data at 18 Mbit/s, add some overhead and some collision/resent ... Try connecting one of the devices with a wired connection and you will see the speed increase by more than double.

link|improve this answer
feedback
up vote 0 down vote

I don't think that speed is especially surprising. Wikipedia gives a typical speed of 10 Mbps. Do you have neighbouring networks on the same channel, or other interference of some kind? Apple has a good list of things to check.

link|improve this answer
For PAN and LAN standards like WiFi, these levels of performance are attainable under ideal radio conditions (that is, a complete lack of interference and at close range without obstacles). – Nitrodist Jul 27 '10 at 13:03
feedback
up vote 0 down vote

Gen has a good point, all traffic to the router is competing with all traffic from the router, including both sides of a file transfer.

I would add, the Netgear DG834G is not a high performance router.

link|improve this answer
feedback

Your Answer

 
or
required, but never shown
discard

Not the answer you're looking for? Browse other questions tagged or ask your own question.