[uqmi] dms: add --get-operating-mode

[Sergey Ryazanov]

On Sun, Dec 5, 2021 at 9:57 PM Henrik Ginstmark <henrik at ginstmark.se> wrote:
> I'm working for a cellular operator and I have the possibilities to monitor the
> registration of the modem from the network side. The registration of an LTE
> terminal is clearly described in the 3GPP specifications and I don´t agree with
> the options you mention. An LTE terminal can not register with an invalid APN.

Yep. I rechecked the 3GPP TS 23.401 and found that the network may
allow APN-less registration for IoT devices, regular modems do not
fall into this category. Oops. I should recall these IoT specific
stuff earlier. And I am sorry for my mistake.

The only thing left to do is to deal with the network responsibility
for the default APN (P-GW) providing. The same specification said that
a network *should* use a default APN if a registering UE (modem) does
not provide any. As someone familiar with the operator business, could
you please estimate how many operators do not utilize the default APN
feature?

> I have created commands for profile modification. But they are not polished ;)
> --get-profile-settings <val,#>:   Get APN profile settings (3gpp, 3gpp2),#\n" \
> --get-default-profile-number <val>:  Get default profile number (3gpp,
> 3gpp2)\n" \
> --modify-profile <val>,#          Modify profile number (3gpp, 3gpp2)\n" \
>   --apn <apn>:                    Use APN\n" \
>   --pdp-type ipv4|ipv6|ipv4v6>:   Use pdp-type for the connection\n" \
>   --username <name>:              Use network username\n" \
>   --password <password>:          Use network password\n" \
>   --auth-type pap|chap|both|none: Use network authentication type\n" \
>
>
> But, if you don't see any benefit with my proposal I´m fine.

I should say sorry if my stream of questions looks like an objection
against your proposal. The described situation with the inability to
register without a preconfigured APN just looks so strange that I can
not resist a wish to investigate it :) Moreover, as an occasional LTE
modem user, I will be the man who benefits from your work once it is
integrated into the uqmi utility.

The only thing that worries me is, should we do the default APN
reconfiguration (via the airplane mode toggling) automatically in
qmi.sh, or should we only provide an ability without forcing it? I am
afraid that while trying to automatically solve one rare issue, we
unintentionally break a lot of running setups by triggering a modem
bug in the airplane mode exiting procedure. Anyway, I am just an
occasional project contributor, not from the core developers staff, so
you can ignore my thoughts all together ;)

> Den sön 5 dec. 2021 kl 18:56 skrev Sergey Ryazanov <ryazanov.s.a at gmail.com>:
>> On Sun, Dec 5, 2021 at 7:43 PM Henrik Ginstmark <henrik at ginstmark.se> wrote:
>>> My intention was to speed up the registration to the LTE network.
>>
>> If we talk about a modem that is part of a router, then I doubt
>> whether the airplane mode activation will be able to speed up the
>> registration procedure. After a router power on, the main router
>> firmware should complete its own boot process before it will be able
>> to switch the modem into airplane mode. But the modem will be powered
>> in the same time as the router CPU and most probably the modem will
>> boot faster. So when the main firmware becomes ready, the modem will
>> be already registered with a network. And triggering the airplane mode
>> will only delay data communication readiness.
>>
>> It would be nice to have the mode configuration command in the uqmi
>> utility. But toggling the airplane mode in an automatic fashion can be
>> even dangerous (see below).
>>
>>> When the LTE terminal is powered on it will attach with the modem
>>> default APN profile. If that is empty, then the network will assign the
>>> network default APN and you get an IP address.
>>>
>>> But if the modem default APN is incorrect, or if your operator does not
>>> assign a default APN, you will be rejected in LTE and the modem will,
>>> after a while, register to 3G, since you don´t need a valid APN to
>>> register to 3G.
>>
>> Please be more specific, what modem model and operator do we talk
>> about? As I showed earlier, a modem has a lot of options during
>> network registration, and earlier community experience suggests that
>> it is most probable that a modem will register with a network smoothly
>> even without an earlier preconfigured APN. So we should make our
>> discussion more specific.
>>
>>> But if we verify that the modem default APN is correct, before we do the
>>> registration, we will be sure that the registration goes smoothly.
>>> The modem will store the default APN setting.
>>
>> When you talking about the default APN did you mean the first
>> connection profile? There are only two commands that carry APN:
>> profile creation and network start. Network start should be called
>> after the network registration completion, while the profile
>> configuration command is not yet implemented.
>>
>>> My proposal to qmi.sh, roughly.
>>>
>>> Check PIN
>>> Check data format 802.3/raw-ip
>>> Check modem default APN settings
>>> If the default APN setting are incorrect,
>>>   Airplane mode on
>>>   Change default APN settings
>>>   Airplane mode off
>>
>> This is my primary concern. How many modem models will reliably exit
>> the airplane mode without any issues?
>>
>>> Check operator and radio technology
>>> run --start-network with client_id wds
>>>
>>> I don´t think this will break anything and you can still have
>>> the possibility of adding a secondary APN.

-- 
Sergey