ModemManager and pppd/NetworkManager integration

[Dan Williams]

On Mon, 2015-03-30 at 15:23 +0200, Francesco Andrisani wrote:
> Ok Aleksander...i know now.
> But why (using mmcli) i'm not able to see ip address of connected modem? I
> see only "address: 'unknown'".

Because the modem doesn't know the IP address, and therefore
ModemManager doesn't know it either.  Only PPP negotiation will provide
the IP address and the usable ppp0 network port, and that is done by
pppd.  That's what 'method: ppp' means, that you need to start a PPP
session to get IP connectivity.

Dan

> Thanks and Regards
> 
> On Mon, Mar 30, 2015 at 2:57 PM, Aleksander Morgado <
> aleksander at aleksander.es> wrote:
> 
> > 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
> >
> 
> 
> 
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