MC7455 on Rasp Pi 3

Gabriel Kuri gkuri at
Tue Sep 19 05:21:44 UTC 2017

Hi Aleksander,

> How are you managing the connection? Are you getting any specific error?

I'm using the built-in debian/Raspbian network start/stop scripts. The
card shows up as wwan0 automatically and I have the start/stop scripts
set to run mbim-network start/stop appropriately and set the static

There's a check script that runs in cron to check the connection and
if it's not up (I can't ping some outside addresses), it'll bounce the
interface and wait to see if it comes back. After doing that about 5
times, if the Internet connection doesn't come back, it reboots the

I don't really have it set up to grab any diags or logs before I
bounce the interface in my check script. What would I look for?

> In general I'd advise to use ModemManager along with NetworkManager,
> as that allows for automatic reconnections by configuring the
> connection settings to autoconnect in NM, and NM also knows exactly
> what needs to be done to get the setup connected.

I'm not familiar with MM and NM. Are they cli based? There's no gui,
this is purely an embedded device.

> You can also use mbim-network but you need to consider that the IP
> settings may need to be set manually in the network interface if DHCP
> doesn't work. Also, this won't do automatic reconnections for you.

Currently, I have the RPi setup to run mbim-network start/stop and
also sets the static IP:

# cat /etc/network/interfaces

auto wwan0
iface wwan0 inet static
        pre-up mbim-network /dev/cdc-wdm0 start
        pre-down mbim-network /dev/cdc-wdm0 stop
        address 24.221.x.x
        gateway 24.221.x.x

> Setting up an autoconnect profile in the modem may also be an option,
> if there isn't one already. Although that isn't support via MBIM, you
> would need to use QMI over MBIM and --wds-set-autoconnect-settings in
> qmicli operations.

I'm not familiar with the autoconnect profile, is it set up through AT commands?

I'm not really sure if I should have a more elaborate start/stop
script to change other settings or just go with the mbim-network
start/stop? If you think MM and NM would be the better way to go and
they're cli based, I'd be happy to give it a try.

Thanks ...

More information about the libmbim-devel mailing list