Resetting Bearer on OpenWRT

[James Hilliard]

On Mon, Oct 15, 2018 at 3:12 AM Aleksander Morgado
<aleksander at aleksander.es> wrote:
>
> Hey!
>
> > I'm running modemmanager on OpenWRT and am getting this error fairly
> > regularly such as when I use AT commands to manually change LTE
> > bands(is there a better way to change/lock bands than using AT
> > commands?): "Bearer not allowed to connect, not registered in 3GPP
> > network"
> >
>
> If you're using ModemManager, you can also use mmcli directly, e.g.
> "mmcli -m 0 --set-current-bands="eutran-2|eutran-3|eutran-4"
> The list of supported bands should be given in the "mmcli -m 0"
> output. Changing bands, of course, will trigger a network
> unregistration and re-registration, and so the device will get
> unregistered in the process.
>
> > Doing "ifup broadband" resolves the issue(at least until it loses the
> > bearer again) since resetting the interface triggers
> > proto_modemmanager_setup() to flush and reset the bearer but I don't
> > see a way to automatically get modemmanager state change notifications
> > to OpenWRT so that I can trigger the bearer reload directly from the
> > modemmanger state change event. I assume that's because modemmanager
> > uses dbus and OpenWRT uses ubus right? I've used a cron job as a
> > workaround to monitor the bearer and issue an "ifup broadband" when
> > it's lost.
> >
>
> One thing you need to consider is that, if I'm not mistaken, the
> netifd integration done in OpenWRT does *not* consider automatic
> reconnections. So if your modem gets disconnected due to any reason
> (e.g. unregistered from the network because you changed bands in use)
> then you'll need to manually trigger a reconnection (e.g. with "ifup
> broadband" as you were doing). I'm sure this can be changed somehow to
> autoreconnect, but didn't spend much time on that after doing the
> initial MM integration in OpenWRT.
>
> The script you're using, where you just look for the bearer state in
> MM and trigger a manual interface up event in netifd if the bearer is
> disconnected, is one way to have the automatic reconnection logic
> working, yes :)
How difficult would it to be to add minimal ubus support for triggering
automatic re-connections as a compile time option?
>
> --
> Aleksander
> https://aleksander.es