Hey,
Am 05.11.2018 um 10:51 schrieb 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.
I suspect you are wrong here: Without the default LTE bearer, there is
no LTE connection possible at all using TOBY with specific providers
(Telekom.de, Telekom.cz), since the network provides default values, but
these values are not suitable to get a functional LTE connection.
Instead you get routed to a non-functional APN ('nodata.telekom.de'). (I
am not sure why the do it that way, it seems they want to force the user
to specify the APN settings explicitely, e.g. to provide several APNs
with different services using the same SIM card? Just guessing ...)
These cards are not special SIM cards, these are the normal LTE SIM
cards every customer gets (and the they are the biggest provider in
Germany). None of these cards can be used with ModemManager at the
moment with the TOBY modem.
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.
Unless I know any other method to make LTE work with the telekom SIM
cards, I suspect the network manager has to change the LTE default
bearer somehow.
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?
This does makes sense when we assume that the default LTE bearer is only
needed in rare cases, which apparently isn't true for the SIM cards we
are talking about.
--
Best regards / Mit freundlichen Grüßen / Salutations distinguées
Ulrich Mohr
SEMEX-EngCon GmbH
Carl-Merz-Strass 26
76275 Ettlingen
Phone: +49 (0) 7243 5143596
email: u.m...@semex-engcon.com
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