initial bearer apn

[Aleksander Morgado]

>
> How is the initial-attach-ip-type decided in the NM MR you shared? I've seen in a network in New Zealand where initial-attach-iptype has to be IPV4 and then it can be changed to IPV4V6 during connection establishment.
>

I assume this could happen if the APN used during connection is
different to the one used during initial attach? But this is
definitely interesting; do you happen to have debug logs of MM on that
setup to confirm your assumption?

> Also, modem might have already gone through registration process before "--3gpp-set-initial-eps-bearer-settings" is called. So when are we supposed to call "mmcli --3gpp-set-initial-eps-bearer-settings"?
>

Yes, the modem always boots and attempts to register in the network
automatically, that's the default. For initial attach it would use
whatever it had configured. If you're using a device that comes with
carrier-specific configs, the default config may already be the
correct one for you. If you are using a generic firmware, there could
be no explicit initial attach APN configured by default, but the
network may be fine with providing you the correct one during the
initial attach. You will need to use
"--3gpp-set-initial-eps-bearer-settings" if e.g. you're not able to
automatically register in the network and you know for sure the
network you're trying to attach is the expected one. ModemManager
dumps some warnings when attach failures happen, and we should
definitely try to update the DBus API to expose those there as well
(see https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/715)

-- 
Aleksander