ModemManager and pppd/NetworkManager integration

[Aleksander Morgado]

On Mon, Mar 30, 2015 at 2:43 PM, Francesco Andrisani
<francesco.andrisani at acotel.com> wrote:
> Hi,
> thanks for you reply.
> Unfortunately I can not use NM 1.0 and even compile. I tried to use the
> commands that I've shared, but I get the following output:
>
> # mmcli -m 0
>
> /org/freedesktop/ModemManager1/Modem/0 (device id
> 'f85b28e50e46a2052dfefb8238550fd2cbc4b88b')
>   -------------------------
>   Hardware |   manufacturer: 'SIMCOM_Ltd'
>            |          model: 'SIMCOM_SIM900'
>            |       revision: 'Revision:1137B01SIM900M64_ST_ENHANCE'
>            |      supported: 'gsm-umts'
>            |        current: 'gsm-umts'
>            |   equipment id: 'xxxxxxxxxxxxxxxx'
>   -------------------------
>   System   |         device:
> '/sys/devices/platform/orion-ehci.0/usb1/1-1/1-1.1'
>            |        drivers: 'ftdi_sio'
>            |         plugin: 'Generic'
>            |   primary port: 'ttyUSB3'
>            |          ports: 'ttyUSB3 (at)'
>   -------------------------
>   Numbers  |           own : '350xxxxxxx'
>   -------------------------
>   Status   |           lock: 'none'
>            | unlock retries: 'unknown'
>            |          state: 'connected'
>            |    power state: 'on'
>            |    access tech: 'unknown'
>            | signal quality: '75' (cached)
>   -------------------------
>   Modes    |      supported: 'allowed: any; preferred: none'
>            |        current: 'allowed: any; preferred: none'
>   -------------------------
>   Bands    |      supported: 'unknown'
>            |        current: 'unknown'
>   -------------------------
>   IP       |      supported: 'ipv4'
>   -------------------------
>   3GPP     |           imei: 'xxxxxxxxxxxxxx'
>            |  enabled locks: 'none'
>            |    operator id: '22201'
>            |  operator name: 'I TIM'
>            |   subscription: 'unknown'
>            |   registration: 'roaming'
>   -------------------------
>   SIM      |           path: '/org/freedesktop/ModemManager1/SIM/0'
>
>   -------------------------
>   Bearers  |          paths: '/org/freedesktop/ModemManager1/Bearer/1'
>
> root at mauNone:~/NM# mmcli -b 1
> Bearer '/org/freedesktop/ModemManager1/Bearer/1'
>   -------------------------
>   Status             |   connected: 'yes'
>                      |   suspended: 'no'
>                      |   interface: 'ttyUSB3'
>                      |  IP timeout: '20'
>   -------------------------
>   Properties         |         apn: 'foo.mycarrier.com'
>                      |     roaming: 'allowed'
>                      |     IP type: 'none'
>                      |        user: 'none'
>                      |    password: 'none'
>                      |      number: 'none'
>                      | Rm protocol: 'unknown'
>   -------------------------
>   IPv4 configuration |   method: 'ppp'
>                      |  address: 'unknown'
>                      |   prefix: '0'
>                      |  gateway: 'unknown'
>                      |      DNS: none
>   -------------------------
>   IPv6 configuration |   method: 'unknown'
>
>
> ....from here I can not go on
> I don't understand when you say "PPP: you'll need to launch pppd on the
> specified TTY port.".
>

pppd is a daemon that will allow you to establish a PPP session on the
already-connected TTY port. In this case, ModemManager was able to
connect (put in 'connected' mode) the ttyUSB3 serial port. Once MM has
done that, pppd needs to be launched on that ttyUSB3. pppd will create
a ppp0 network port, which is the one giving you the IP connectivity.
Usually NetworkManager is in charge of doing that, but if you cannot
use it, then you'll need to have an additional setup to get pppd
launched once ModemManager exposes the IP details in DBus.

-- 
Aleksander
https://aleksander.es