3G Connections With Ubuntu Intrepid Ibex


    So, in previous posts, I have discussed how to use Bluetooth and Personal Area Networking (PAN) to connect your Ubuntu computer to a Windows Mobile SmartPhone for Internet access. That was one way to get Internet access while on the go, but with the imminent release of Ubuntu's Interpid Ibex (8.10) there is supposed to be better support for 3G Internet connections. I decided today to test that theory.

    First, let begin this discussion by explaining what I am using to perform the tests. I have a Toshiba Satellite laptop running the latest updates from the Ubuntu repositories for 8.10. My phone is a HTC 8525 from AT&T running Windows Mobile 5.0. The 8525 comes with a program called "Internet Sharing", which has two options: Bluetooth and USB. In my older post, I showed you how to connect via Bluetooth, and overall that has not changed in the latest Ubuntu release.

    The big change in Intrepid is that the USB tethering finally works well and easily. The new Network Manager application including in Intrepid is supposed to have better support for 3G data networking. Earlier this week, and associate and I tested this out with his USB connected cellular network adapter. It works intuitively and easily. We plugged in the USB adapter and instantly the network manager application started automatically configuring and connecting. We were up and running in seconds. No package installations, to command-line, no software configuration.

    With that success fresh on my mind, I decided to try my luck with my regular smartphone. So, on the smartphone, I fired up the Internet Sharing application and set it for USB. When I plugged it in to my Ubuntu laptop, the result was the same as my test with the USB network adapter. There was no configuration required, no software to install, and within seconds I was connected to the Internet with excellent performance.


    So, the first thing I tested once I was up and running was to go to SpeedTest.net. I tried several times to run the test, but after about 1.2MB of transfer, the connection would stall. I could continue to other sites and other downloads, but I could not complete a full test. This appears to be a throttling application on the AT&T network.

    Next, I tried my personal favorite performance test, downloading a Linux kernel source package from kernel.org. Again, after about 1.2MB, the download would stall and had to be started over.

    After some investigation with WireShark, I came to determine that the problem was not the oft publicized RST flag in the TCP connection. In fact, this problem turned out to be that the network kept resending the same ACK segment repeatedly. This creates the exact indications I was seeing on the downloads.

    So, it appears from my basic analysis that AT&T throttles connections. Annoying, but not at all unexpected. Before the connections stall, I was able to achieve ~850kbps download, and ~700kbps upload. Not a bad result, but those numbers are not very reliable based on the stalled connections not allowing more than a few seconds of sustained throughput.


    So, my conclusion is that the tools in Ubuntu Intrepid Ibex are vastly superior to previous iterations. Overall, the network manager works well and is a significant improvement over previous iterations. As for the performance, I can tell you that for normal web browsing it works great, but for large downloads I could not get a fair assessment. Happy Computing!!!


Ken said…
I have attempted the same thing and not got beyond pairing the phone. I use ubuntu 8.10 and a nokia 6125. I can get my laptop (an Acer Aspire 1310) to pair with the phone, but from there, I can't see how to get them to connect. The net manager does have preset connection parameters for my cell supplier (Rogers) and I have those set. But what do I do to instigate a connection?
Deven Phillips said…
Ken, the article above relates specifically to a USB connection and not Bluetooth. There is no graphical Bluetooth configuration as far as I am aware. I have written an article about how to accomplish this using the Personal Area Network Daemon (PANd) which you can read HERE

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