Modem not connecting on Ubuntu 16.04 (whereas it did on Ubuntu 14.04)

[Aleksander Morgado]

On Tue, Aug 30, 2016 at 8:56 AM, Ajay Garg <ajaygargnsit at gmail.com> wrote:
> The reason turned out that I had disable USB-3.0 support in BIOS.
> When I turned it on, the modem started connecting in both 14.04 and 16.04.
>
> However, in 14.04 the "wwan" interface appears fine (and after running
> "dhclient" on it, the internet works fine).
> However on 16.04, no "wwan" interface appears, even after mmcli -m 11
> --simple-connect="apn=airtelgprs.com" has resulted in successful-connection.
>
>
> A maybe related symptom is that ethernet-interfaces appear as "eth0" and
> "eth1" in 14.04, but as "enp1s0" and "enp2s0" in 16.04. But even then, NO
> ADDITIONAL INTERFACE appears when mmcli -m 11
> --simple-connect="apn=airtelgprs.com" has resulted in successful-connection
> on 16.04.
>
> Looks very weird; I will be thankful for any help.

--simple-connect doesn't make interfaces appear/disappear :) The WWAN
interface should be detected and available before you even attempt to
run --simple-connect.

Looks like you have now the "predictable network interface names"
support in Ubuntu 16.04, coming from systemd:
https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/

This means that you won't have a "wwan0" interface any more; look for
something like "ww...."

Anyway, the correct flow is to avoid manually looking for the network
interface name. Once you have run "--simple-connect", you'll have a
connected "bearer" object reported in ModemManager. The bearer object
will tell you, in its details, what interface name you should use and
also the specific connection method you're supposed to use (dhcp,
static, ppp).

-- 
Aleksander
https://aleksander.es