lab1

Hi,

I'm using an Huawei E180 modem with Linux kernel 2.6.28 (Ubuntu 9.04). The transfer rate is OK but not as good as it is when I use the same modem (in exactly the same location) in Windows.

With Windows XP I get:

Download: 3 - 5 Mbit/s
Upload: 1 - 1.4 Mbit/s

With Linux I get:

Download: 3 - 5 Mbit/s
Upload: 0.6 - 0.8 Mbit/s

I thought this was just coincidence but I have tried it time after time with the same sad result
The upload speed will never exceed 0.8 with Linux.

This modem uses the "option" driver which also loads the "usbserial" driver, I have checked the initialization (AT-commands) that are done in Windows and I think I'm running the same in Linux. Have also tried several different PPP options but no improvement.

Through /dev/ttyUSB1 the modem reports: ^MODE: 5,7 which should indicate HSPA (HSDPA+HSUPA) mode (same as in Windows).

I know from other posts that the "usbserial" driver has some throughput issues but that should not be the case for the option driver or?

The upload speed looks like it's stuck at HSUPA category 1 (0.73 Mbit/s) although my ISP is using 2 or 3 (1.46 Mbit/s). At least they say that upload is limited to 1.4 Mbit/s.

So my questions:

1. Has anyone on this forum got a better than 0.8Mbit/s Upload transfer rate using then option driver (with any modem)? If so did you do any tuning or anything else to get it?

2. The option driver also loads the usbserial driver which has known throughput problems, could the usbserial driver be the one causing this limitation?

TIA

lab1

I had a look in the option driver kernel source for 2.6.30.1 and noticed that there were some changes regarding transmit buffers and other stuff that might affect the transfer rate.

So I compiled a custom 2.6.30.1 kernel for my Ubuntu 9.04 installation and that solved the problem, I now get the same transfer rate in Linux as I get in Windows

Yes... I know it would have been a good idea to check that before asking the question