Multiple Modems (USB Dongle) problem

[Aleksander Morgado]

Hey John,

On Sat, Oct 17, 2015 at 3:16 PM, John Whitmore <arigead at gmail.com> wrote:
> This is a development list so possibly the wrong place for this question but
> please redirect me as necessary.
>

No, this is the correct place to ask :)

> I've got a problem using two USB LTE Dongle modems of exactly the same
> model. They each have a different operators SIM installed. They will both get
> added to the linux system (I'm using Arch on a RPi-2) as /dev/cdc-wdm0 and
> /dev/cdc-wdm1. BUt they will be added, I imagine, at random.
>
> Managing which is which is the job of UDEV rules so I've added the necessary
> rules to create symbolic links to the two modems as /dev/three and
> /dev/vodafone.
>
> That all works great my problem is that in the network manager when I add a
> connection it only offers me the devices /dev/cdc-wdm0 and /dev/cdc-wdm1. NOT
> my new symbolic links.
>

Have you tried to rename the interfaces, as systemd does with the WWAN
net interfaces and the "predictable network interface names" setup?
You should need to do that before the MM udev rules are used.

> So given that it's the NetworkManager agian this might be considered the wrong
> list.
>
> Maybe I should explain the system here. This is going into an RPi-2 in a boat
> that floats about a lake. So mobile coverage will change between the two
> operators. I'm taking this one step at a time and ultimately I'd like the
> system to use which ever connection it can. That might be a problem as the
> boat needs to have a web site open on the browser. That web page is used to
> upload data so the web page is opened and the boat floats about the lake
> populating forms in the web page. If the web page is connected via one
> connection and the connection changes that might cause a problem. I've not got
> there yet. Like I say one step at a time.
>
> This might not even be a problem. I mean maybe the NetworkManager creates a
> connection, but then the ModemManager has the intelligence to say that you're
> trying to open the "vodafone" connection on the wrong modem and just take care
> of it?

So, the thing here is that NetworkManager should allow binding a given
set of mobile broadband settings to a given specific device (based on
'Equipment ID') or SIM (based on ICCID or even MCCMNC); e..g as it can
be done with binding settings to a network interface based on the MAC.
If that is done, NM would be intelligent enough to enable the correct
settings in each modem.

Dan, what's the status of this in NetworkManager? Was any change done recently?

-- 
Aleksander
https://aleksander.es