Very Slow Transfer Speed Over Wireless Network (Solved)

[mechanism]

Searching the forums and other places on the net reveals that slow transfer speeds over networks have been a well documented issue. However, I've not found any posted solutions. Just more questions

I'm running Kubuntu 7.10, A wireless Linksys WMT54G card and a Linksys router. On the same network is a network storage device (HP Media Vault) which I connect to using NFS. Transferring anything from my Linux PC to the Media Vault results in transfer speeds of about 55 to 90 KB/sec transfer speed. I can not find a solution to this problem.


Does anyone have any tips or things to try?

Thanks,

Mike

[mechanism]

Re: Very Slow Transfer Speed Over Wireless Network

Anyone?

[mechanism]

Re: Very Slow Transfer Speed Over Wireless Network


There seems to be a solution for this. I'm not sure of the technical details but you can read all about it here:
http://www.linuxforums.org/forum/deb...tml#post481387

It seems there is a problem/issue/bug/opportunity for improvement in kernels of the 2.6.17 vintage and newer. It has to do with TCP window scaling...I'll save you the details since I'm not exactly sure what they are talking about. It's in the above referenced link so read for yourself if you are interested.

HOWEVER - the fix involves resetting some TCP protocols by using the following commands as quoted here...

"There are 2 quick fixes. First you can simply turn off windows scaling all together by doing

echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

but that limits your window to 64k. Or you can limit the size of your TCP buffers back to pre 2.6.17 kernel values which means a wscale value of about 2 is used which is acceptable to most broken routers.

echo "4096 16384 131072" > /proc/sys/net/ipv4/tcp_wmem
echo "4096 87380 174760" > /proc/sys/net/ipv4/tcp_rmem

The original values would have had 4MB in the last column above which is what was allowing these massive windows."

When I try to excute the above commands I get a "permission denyed" error even as root. Does anyone know how to execute these commands.

[kubicle]

Re: Very Slow Transfer Speed Over Wireless Network

When I try to excute the above commands I get a "permission denyed" error even as root. Does anyone know how to execute these commands.

Are you trying to do:

sudo echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

?

If you are, the redirection (>) is done by the shell which is still running as a regular user >> 'permission denied'

either start a root shell ('sudo -s' should do) or do something like:

echo 0 | sudo tee /proc/sys/net/ipv4/tcp_window_scaling

[mechanism]

Re: Very Slow Transfer Speed Over Wireless Network (Solved)

Problem solved

I tried and tried many different settings and commands and tests...all of them never improved my speed beyond 300 KB/sec which is very slow considering I'm using a 54 Mb/sec router. Anyway, on a hunch, I switched from kernel version 2-6-22-14 Generic to 2-6-20-15 and my network speeds immediately jumpted up to 2 Mb/sec and I've seen as high as 25 Mb/sec.

I can not explain why this works but it does. Actually, my entire system seems a bit more peppy on this kernel. I have made this kernel my default.

I hope this helps someone.

Mike