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-   -   WLAN performance (http://www.linux-archive.org/gentoo-user/59406-wlan-performance.html)

Florian Philipp 03-21-2008 09:33 AM

WLAN performance
 
Hi list!

Can anyone tell me how I could find the bottleneck on my wireless
network? According to iwconfig, both cards are cofigured for 54 MBit/s
but I only get about 13 MBit/s, both on NFS and scp.

Might it be the driver (iwl3945, rt61 from kernel 2.6.24)?
Unfortunately, iwspy doesn't work on these cards.

William Kenworthy 03-21-2008 09:55 AM

WLAN performance
 
ahh, marketing. Some people will believe anything!

Check the table at
http://www.oreillynet.com/pub/a/wireless/2003/08/08/wireless_throughput.html

or numerous other guides courtesy of google. This shows that maximum
throughput is roughly 27Mb/s for 54g, but in my experience its much less
in the real world.

Note that configuring a card for 54mb/s is the maximum - unless you are
quite close (distance wise), have little interference and dont have a
busy 802.11b on the same AP, you are not even going to see a 54, but a
fallback. And I think encryption will clip it even further if you are
using that (as you should be!)

BillK


On Fri, 2008-03-21 at 11:33 +0100, Florian Philipp wrote:
> Hi list!
>
> Can anyone tell me how I could find the bottleneck on my wireless
> network? According to iwconfig, both cards are cofigured for 54 MBit/s
> but I only get about 13 MBit/s, both on NFS and scp.
>
> Might it be the driver (iwl3945, rt61 from kernel 2.6.24)?
> Unfortunately, iwspy doesn't work on these cards.
--
William Kenworthy <billk@iinet.net.au>
Home in Perth!
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gentoo-user@lists.gentoo.org mailing list

Stroller 03-21-2008 01:36 PM

WLAN performance
 
On 21 Mar 2008, at 10:33, Florian Philipp wrote:

... both cards are cofigured for 54 MBit/s
... I only get about 13 MBit/s, both on NFS and scp.


I'd be really quite happy with that.

As BillK remarks, 50% of your 54 Mbit is consumed by protocol
overhead. You're probably going to tell us that the two machines are
currently right next to each other, so losing an additional 50% to
interference & other intangibles might seem at first sight
unreasonable, but I doubt you'll ever do any better than that, and
you could waste a lot of time trying.


Wireless is for surfing on the sofa - you can easily get eighty times
this throughput with a cable, so investing time & energy in trying to
get a two-times performance increase is a poor return.


Stroller.
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