Mobile Broadband Modem disconnects, disappears from NetworkManager list

[NoahY]

Once in a while my mobile broadband modem just disconnects and disappears from the network indicator in the status bar. Syslog has this to say:

Oct 7 17:56:37 X58A-UD3R pppd[4193]: LCP terminated by peer
Oct 7 17:56:37 X58A-UD3R pppd[4193]: Connect time 22.8 minutes.
Oct 7 17:56:37 X58A-UD3R pppd[4193]: Sent 1202109 bytes, received 22074370 bytes.
Oct 7 17:56:37 X58A-UD3R pppd[4193]: Modem hangup
Oct 7 17:56:37 X58A-UD3R pppd[4193]: Connection terminated.
Oct 7 17:56:37 X58A-UD3R avahi-daemon[1358]: Withdrawing workstation service for ppp0.
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> (ttyUSB0): device state change: activated -> failed (reason 'ppp-disconnect') [100 120 13]
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <warn> Activation (ttyUSB0) failed.
Oct 7 17:56:37 X58A-UD3R modem-manager[1297]: <info> (ttyUSB0) closing serial port...
Oct 7 17:56:37 X58A-UD3R modem-manager[1297]: <info> (ttyUSB0) serial port closed
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> (ttyUSB0): now unmanaged
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> (ttyUSB0): device state change: failed -> unmanaged (reason 'removed') [120 10 36]
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> (ttyUSB0): deactivating device (reason 'removed') [36]
Oct 7 17:56:37 X58A-UD3R modem-manager[1297]: <info> Modem /org/freedesktop/ModemManager/Modems/2: state changed (connected -> disconnecting)
Oct 7 17:56:37 X58A-UD3R modem-manager[1297]: <info> Modem /org/freedesktop/ModemManager/Modems/2: state changed (disconnecting -> connected)
Oct 7 17:56:37 X58A-UD3R dbus[1284]: [system] Activating service name='org.freedesktop.nm_dispatcher' (using servicehelper)
Oct 7 17:56:37 X58A-UD3R dbus[1284]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <warn> could not read ppp stats: No such device
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: nm_system_iface_flush_routes: assertion `ifindex > 0' failed
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: nm_system_iface_flush_addresses: assertion `ifindex > 0' failed
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> Clearing nscd hosts cache.
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> (ttyUSB0): cleaning up...
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> (ttyUSB0): taking down device.
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Oct 7 17:56:37 X58A-UD3R NetworkManager[1403]: <info> disconnect failed: (32) The serial port is not open.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: ppp 2.4.5-5ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-12.19-generic 3.0.4
Uname: Linux 3.0.0-12-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 1.23-0ubuntu2
Architecture: amd64
Date: Fri Oct 7 18:04:31 2011
ExecutablePath: /usr/sbin/pppd
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
ProcEnviron: PATH=(custom, no user)
SourcePackage: ppp
UpgradeStatus: Upgraded to oneiric on 2011-08-27 (40 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Michael Z. Krog (mic-apaq)]

I see this too.

I have a setup where my ubuntu server shares its ,mobile connection(via usb modem) to other computers.
The pattern I see is that it get disconnected every single night and I have to reinsert the modem and type in
the pin again to make it work.

[jsmanian (jsmanian79)]

I am also having same but in ubuntu 12.04 LTS

[Stéphane Graber (stgraber)]

The syslog shows a modem hangup so not something ppp can do much about.
I'd expect network manager to tell you that you got disconnected and then you should be able to select that network again, if that's not the case, then there's probably a bug somewhere in modem-manager or network-manager.

[Daniel Gonzalez (danielglz888)]

Hello.
I have the same problem. Thank you.

[Reynaldo Matos Hortensi (lasanhadeberinjela)]

Hi dudes.
Same problem. I just "sudo service modemmanager restart" and reconnect.
Sometimes it happens each minute and sometimes it doesn't happens for all night and IDK why.