I'm using IBM Lenovo Thinkpad T61p dual booting Ubuntu 8.04 Hardy Heron, and also WinXP, my EVDO Aircard is a Franklin Wireless CDU-680. In Ubuntu I use pppconfig to connect with /dev/ttyACM0.

I'm using Sprint EVDO Rev A, which should give me 240 KB/sec down and at least 100 KB/sec up.

My speed tests are with ftp uploads and downloads.
In Ubuntu
My downloads are about 240 KB/sec.
My uploads will not go over 46 KB/sec.

In WinXP, after registry changes
My downloads are 240 KB/sec.
My uploads are over 100 KB/sec.

I've tried several sysctl tweaks, including changing my MTU lower than 1500, but nothing works. When I use Ethernet my DL and UL speeds are fine.

I've read that there is another way to use my EVDO aircard, without mapping USB to Serial. I don't know about all the different drivers though. I'm using the supplied Franklin Wireless Drivers.

Any ideas?

I realize this is a linux forum but I found this post using google, I'm having the same problem only I'm using Windows XP. I was wondering what registry changes you made to tweak the upload speeds, could you walk me through it?

Sorry it took me so long.
Windows Changes



REG_DWORD Values "DWORD"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Performance

GlobalMaxTcpWindowSize 0Xfaf0

TcpWindowSize 0xfc00

Maybe????

Tcp1323Opts 1

TcpMaxDupAcks 2

SackOpts 1



HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AFD\Parameters

DefaultSendWindow 0xfc00