Version: unspecified OS: Linux When traveling by high-speed train, the modem connects and disconnects often, and switches from UMTS to GPRS etc. Often the reconnecting and switching works. Sometimes the modem is not connected though (light on solid meaning there is a network but no connection) and the network manager reports that it is still connected. Version: haven't tried it with the kubuntu beta, but older versions hat this problem. Reproducible: Always Steps to Reproduce: Connect the modem, travel by high speed train, wait :) Actual Results: KNM reports connection when there isn't one Expected Results: KNM recognised dropped connection and reconnects KNM possibly needs to actively confirm the status from time to time? I assume that events are lost somewhere when the connection state changes too frequently. A manual "Reconnect" option would be good to force the state.
https://bugs.launchpad.net/ubuntu/+source/knetworkmanager/+bug/584457 is possibly related ?
It is NetworkManager daemon that reports the connect/disconnect state to Plasma NM. Probably it is the fact that the modem is at high-speed compared to the operator's antenna that is causing the instability because of the doppler effect in the communication frequency. I do not think that there is a solution besides buying a modem with better attenuation of the doppler effect. This is a hardware issue, not software. Roaming between antennas is quite often when in high speed too and also contributes to the connection instability. How fast is the train? (200 Km/h, 250 Km/h, 300 Km/h, +300Km/h)? There is a button at the left of the ative connection (it disappears if the connection is already disconnected) to disconnect the connection. You can click on it and on the connection's name to reconnect.
I have confirmed this bug again. Both in trains where the connection strength can vary a lot (both in fast and slow sections of the track) as well as in a location with very low signal (grandparents house), where the same thing happens. Basically, the light indicator on the PCMCIA card does not correspond to what the NM reports as the status. Would a log of all NetworkManager and modem-manager entries in the syslog help? The manually disconnecting and reconnecting work fine.
Yes the logs would help. Also send me the Plasma NM, NetworkManager and ModemManager versions you use and the screenshot of the plasmoid's main window when the problem happens.