Re: manage a modem connection

[Aleksander Morgado <aleksander aleksander es>]

Hey

> I have a "e3372h-153" Huawei 4G USB dongle.
>
> This dongle works with the "huawei_cdc_ncm" kernel driver.
>
> Once connected,  two devices appear : /dev/ttyUSB0 and
> /dev/cdc-wdm1.
> These ones are used to talk to the modem itself.
>
> There is also a network interface appearing, which is (I believe)
> related to the driver "huawei_cdc_ncm" and the NCM protocol :
>
> wwx001e101f0000: flags=4098<BROADCAST,MULTICAST>  mtu 1500
>         ether 00:1e:10:1f:00:00  txqueuelen 1000  (Ethernet)
>
> I am able to connect the modem with "mmcli ...", yet still I have
> to configure
> the corresponding network interface in order to access the
> web.

When using only ModemManager/mmcli this is expected, yes. You need to
look for the connected bearer details (e.g. mmcli -b 0 probably) and
then apply the IP addressing changes showed there.

> But this
> interface does not show up with "nmcli device show". I am however
> able to
> issue "dhclient wwx001e101f0000" and it works.

NetworkManager does not refer to the modem based on the network
interface it exposes, it refers to the modem based on the primary
control port exposed by the modem (e.g. cdc-wdm0 probably).

> I also tried "nm-connection-editor". This one finds the modem
> (gsm) but it seems to
> settle a connection through ppp.I would prefer a connection
> through wwx001e101f0000
> because it uses the NCM protocol, known to be faster than PPP.

This is the way to go. If ModemManager doesn't use the cdc-wdm port
plus the network interface for the connection, there must be a reason
for that, we need to find why.

Do the cdc-wdm and the net port show up in the list of ports reported
in "mmcli -m 0"?

> Then, how come that I cannot see and configure wwx001e101f0000
> with nmcli, just like
> any other network (wired, wifi) interface ?

Because that interface is a modem network interface, and so the main
interface that NetworkManager would refer to is the control port, not
the data port (as the data port is chosen dynamically on runtime).

-- 
Aleksander
https://aleksander.es