Hi Marcel, Thanks for your message.
On Thu, Dec 06, 2012 at 12:12:26AM +0100, Marcel Holtmann wrote: > Hi Forest, > > > If the device has retained parameters for a previously defined IP > > context, is is probed via AT+CGDCONT?. > > this is really not a good idea. The AT+CGDCONT? settings are on a per > device basis. That is not how oFono actually works. It operates on a per > SIM card basis. And since you do not know to what SIM card these > previous settings apply to, the only sensible thing to do is to ignore > them. Okay, I was not aware of this. But surely the common case (i.e. the only one I've personally seen) is to have a single SIM card per device, and under those limited circumstances it is safe to assume that the settings are valid for that SIM. Would it be reasonable to implement such a fallback for this more limited case? > You do know that oFono does keep its settings per SIM card persistent. > So no matter what device you enter that SIM card into, the settings will > be available the next time you try to connect. So it is a one time > configuration option. Yes, I do know this. But it's just not a great fit for our use case. We're using ConnMan and oFono to manage networking for computing appliances (e.g. interactive kiosks and digital signs). These are typically deployed in fleets of anywhere from 10 to 10,000 units. Clearly we do not want to manually configure an APN for each machine. ;) Ideally, we try to use a single configuration for the entire fleet to keep the fleet easy to manage. But for a variety of business and technical reasons, multiple service providers may be used within a given fleet. So we can't simply provision a single APN for the entire fleet. What we really want is to be able to plug a modem into the machine and it will Just Work. So we'd like to choose the right APN based solely on information from the modem. I've observed that modems tend to arrive with an IP context pre-configured (including the correct APN). I assume the service provider sets this as part of some internal provisioning process. Perhaps it is not safe to assume that this will be the case with the majority of devices and/or providers. On the other hand, if it is, it seems sensible to make use of that data. The alternative to pulling the data from the device is to provide a mechanism for specifying the APN policy for a particular fleet. (At least in theory the APN selection policy can vary from one fleet to the next.) I assume this would be implemented as a custom provisioning plugin that either hard-codes the policy for the fleet, or provides a configuration mechanism that is flexible enough to accommodate the needs of most fleets (probably using a provider -> APN mapping, assuming we can guess the provider e.g. using the mobile-broadband-provider-info database). So this is probably a little heavier on the configuration side, but at least the policy configuration would be the same over the entire fleet. I think we could live with that. But of course it would be much easier if we didn't have to bother. ;) Thoughts? Thanks, Forest -- Forest Bond http://www.alittletooquiet.net http://www.rapidrollout.com
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