PHARscape

ardealul · Joined: 23 Jun 2008 Posts: 4

Hi All,

I am using the newly released openSuSE 11.0 and finally got my Option HSUPA Modem (Model: GI0301 (Vendor=0x0af0, Product= 0x7251) - 7.2 Mbps Down/2Mbps Up) work with it.

Now, comparing the experience with the same modem used on windows, i find the following two issues that really annoy:

Issue 1: The signal strength that is reported by globetrotter connect (windows) is a LOT (double) better than what hsoconnect reports
Issue 2: The bandwith on Windows is about 300 KBps (that's Bytes, not Bits) while on linux is about 30 KBps (also Bytes - using hso kernel module 1.2, hsolinkcontrol, rezero and hsoconnect - all with the versions specified in the fedora 9 howto - btw, the howto is applicable 100% to opensuse 11.00 too))

edit: Btw, the ping timeouts are also better under Windows (about 30% better) than on Linux.

Anyone has any Idea on how I could debug this ? See what is the show stopper under Linux ?

Thanks for the Help.

Paul · Posted: Mon Jun 23, 2008 11:29 am Post subject:

Hi ardealul,

I cannot comment on openSUSE 11 as I have not installed it yet.

But...

Linux has no effect on the signal received!

There is no "standard" rule to dictate what signal strength is indicated by 1, 2, 3, 4 or 5 bars. This means you cannot compare mobile phones, data-cards or Linux versus Windows by looking at the number of bars displayed.

(For HSOconnect I have chosen a simple linear mapping. I do not know what algorithm is used by other software. )

30 KBs is a good UMTS connection (max speed 384 kbs)
300 KBs is a good HSDPA connection ( perhaps a 3600 Mbs connection)

How did you measure this?

Note: There is no guarantee that you will always get a connection at HSDPA speeds and it will change throughout the day. Did you test these connections more than once at the same time of day and at different times of day?

Did you test them on the same machine in the same location?

Ping times will also vary - HSDPA gives a better ping response than simple UMTS.

My advice is to test the connection several times (at different times of day) using a reliable speed test.

Cheers,
Paul

ardealul · Joined: 23 Jun 2008 Posts: 4

Hi Paul,

thanks for the response. Both HSOconnect (linux) and globetroter connect (windows) report a hsdpa connection so from a physical layer point of view it should be more or less the same conditions.

Now, my guess is that somewhere in the way hsoconnect works, there is an incompatibility with the modem i am using in that it connects actually via umts and not hsdpa.

I was curious to know how the various components interract (hsoconnect, hso kernel module, hsolinkcontrol, etc) so that i may figure out where the problem lies. I did indeed not use the same machine for the two tests, but they are living 20 cm from each other and did the two tests (by downloading the same file from the same location) in a 2 minute time frame.

The idea is that i would really want to convert my girlfriends laptop to linux and this would be a show-stopper for her.

Every time i get into these kind of problems (ease of installation) i strongly ask myself why the blip there is no common driver framework for linux (there is actually but nobody uses it - talk about open source and standards)

Thanks for your help

ardealul · Joined: 23 Jun 2008 Posts: 4

just tried it on the same machine on ubuntu 8.04 (using the ubuntu howto - which differs only in the udev rule from the fedora howto) .... still the same sluggish speed

Paul · Posted: Mon Jun 23, 2008 10:39 pm Post subject:

Hi ardealul,

HSOconnect sends a few AT commands when it first opens the communication link. These AT commands should not have any affect on speed except the "3G preferred" type commands. It asks hsolinkcontrol to open and close the Internet connection. The program then polls the AT command port periodically to see if there are any messages. I have not done this but you can test if HSOconnect influences the speed by using the connect.sh script to see if there is any difference.

hsolinkcontrol does not do any configuration at the link level it just sets up the routing and DNS server lookup and then opens the connection.

HSO does not configure any port parameters, it just transfers the IP packets.

I only have 2G where I live so speed tests are difficult to do. Wink

It is possible that some port speed configuration is required but I have not investigated this.

I am in an area of 3G coverage this week so I will investigate the speed issue myself.

Cheers,
Paul

ardealul · Joined: 23 Jun 2008 Posts: 4

Hi Paul,

thanks again for your response. I have recompiled some dependencies and now it seems to work ok.

After reading your response though, I can only come to the conclusion that it was just a coincidence and that the actual network (signal, etc) might have been to blame.

Thanks again for your help.