Bug 118043 - kppp:Connection speed setting can cause severe performance deficiency
Summary: kppp:Connection speed setting can cause severe performance deficiency
Status: RESOLVED WORKSFORME
Alias: None
Product: kppp
Classification: Unmaintained
Component: general (other bugs)
Version First Reported In: unspecified
Platform: unspecified Other
: NOR normal
Target Milestone: ---
Assignee: Harri Porten
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2005-12-10 01:00 UTC by esigra
Modified: 2018-11-02 22:38 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


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Description esigra 2005-12-10 01:00:44 UTC
Version:           0 (using KDE Continue)
Installed from:    2.3.1
Compiler:          kppp/general
OS:                X.............

I tried to set up a dialup connection from an isolated location a while ago. I followed the advice in the manual:
"Choose from the list of connection speeds supported by your serial port. Note that the serial port supports much higher speeds than your modem in most cases. You should probably start with the highest number available, and only reduce it if you have connection problems."
I set the speed to the highest value, 460800 and the modem connected at 9600. It was a working connection but with a severe performance deficiency. It was quite difficult to find a workaround, because there are so many things to consider (modem, serial port configuration, kernel configuration, pppd, kppp). When I was there again 8 months later i tried again. This time I got the very unintuitive idea to reduce the connection speed to increase the connection speed. I tried 230400 without success. Still only 9600. But i did not give up there, after having checked the kernel configuration carefully several times, I was determined to try through the whole list of values. Then I was finally lucky with 115200. It made the actual speed rise to around 44000 (with some small variation). So I found the workaround, but it is a serious usability problem that the user should have to use trial and error. Most users would probably not even pay attention to the connection speed (9600) and just think that "Internet access in Linux is dog slow and sucks". And if they do, they have no idea that lowering the connection speed could fix the problem with a too slow connection speed. And even if they try it, they might give up when lowering to 230400 does not help.

Why is there such an unintuitive mapping between configured connection speed and actual connection speed? Why does the software do such a stupid thing as connecting at 9600 and pretend that everything is all right?
Comment 1 Stephan Kulow 2005-12-10 10:22:23 UTC
please specify the versions, you somehow screwed up the reporting.
Comment 2 esigra 2005-12-10 11:42:47 UTC
Version: 2.3.1 (using KDE 3.4.1)
Installed from: Gentoo packages
Compiler: gcc 3.3.6
OS: Linux
Comment 3 András Manţia 2006-05-20 17:27:21 UTC
The problem is that USB modems/serial ports support higher speeds than the traditional ones, and maybe kppp does not check for the type of the port and setting a too high value for serial ports that do not support them results in dropping the speed to 9600...
Comment 4 Andrew Crouthamel 2018-11-02 04:24:22 UTC
Dear Bug Submitter,

This bug has been stagnant for a long time. Could you help us out and re-test if the bug is valid in the latest version? I am setting the status to NEEDSINFO pending your response, please change the Status back to REPORTED when you respond.

Thank you for helping us make KDE software even better for everyone!
Comment 5 esigra 2018-11-02 06:31:19 UTC
I can not test this because I no longer use that computer or a modem. Neither have I a subscription to a service to connect to with a modem.
Comment 6 Andrew Crouthamel 2018-11-02 22:38:58 UTC
Thanks for the update!