[ublox] A problem with the network connection over LTE on TOBY-L2

[Aleksander Morgado]

Hey,

> > Upon connection from e.g. NM, MM will check whether the requested settings (APN, ip-type...) match the ones from the default LTE attach bearer, and if they do, MM will report that the modem is connected right away without trying to create and connect a different context. This is already more or less what the u-blox plugin does. And when disconnecting the connection, if it was the initial default LTE bearer, we'll just report disconnection without touching the actual bearer in the modem (as that would probably return an error). This procedure is IIRC what Microsoft suggests in the MBIM extensions that allow this kind of management, see:
> > https://docs.microsoft.com/en-us/windows-hardware/drivers/network/mb-lte-attach-operations
> >
> Ok, that approach more or less matches the implementation I test at the
> moment, except that I set the default bearer upon first connection
> establishment with that APN (lacking other possibilities to do so).
>
> That leads me directly to the one open point: How will the use case
> works when using Network Manger with your new API?
> The user will enter the APN information to set up the connection
> information (in my case, that will be a device configuration UI). That
> will result in a new (or changed) Network manager connection
> configuration. Now, the Network manager will have to bring the modem to
> low power and set the default LTE bearer and then bring the modem back
> to full power. How will this be done?
>

I am actually not expecting NetworkManager changes at this point. The
fact that someone needs to change the initial default LTE bearer
manually is not a common use case. If the device doesn't have an
explicit config for the SIM card in use, the network provides some
default values (if I'm not mistaken), and that is usually more than
enough in most cases.

>From my point of view, this setting could be a modem-wide setting, to
be treated in the same way as e.g. the allowed/preferred access
technology modes, and so this could be managed in the System Settings
panel, not directly associated to any given connection profile in
NetworkManager. NetworkManager won't do any automagic to change the
default initial LTE bearer settings in the device.

So, if a user does require to change the default initial LTE bearer
settings, two steps would be required: change the settings in the
modem (e.g. via System settings or mmcli) and then setup a
NetworkManager connection profile with those same settings.

Does this make sense?

> BTW: Since I did an implementation that works for me, I could provide
> that source code somehow, if your are interested. I don't think it is
> perfect and will need changes to work the way you plan, but perhaps it
> might help nevertheless? If interested, let me know which works best for
> you how to provide the source code ...
>

A patch to this mailing list would be enough :)

-- 
Aleksander
https://aleksander.es