From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============2889421915624852583==" MIME-Version: 1.0 From: Denis Kenzior Subject: Re: [PATCH 2/2] atmodem: Probe device for previous APN. Date: Mon, 03 Dec 2012 22:41:38 -0600 Message-ID: <50BD7F02.8050900@gmail.com> In-Reply-To: <20121206025456.GC4235@alittletooquiet.net> List-Id: To: ofono@ofono.org --===============2889421915624852583== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Hi Forest, On 12/05/2012 08:54 PM, Forest Bond wrote: > 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 fo= r that > SIM. Would it be reasonable to implement such a fallback for this more l= imited > case? > I admit your approach did make me chuckle for being so unorthodox :) = However, I think your perception is slightly wrong, there are people who = switch sim cards like crazy (e.g. frequent travelers) so this form of = provisioning is not really a good idea in those cases. >> 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 applianc= es > (e.g. interactive kiosks and digital signs). These are typically deploye= d in > fleets of anywhere from 10 to 10,000 units. Clearly we do not want to ma= nually > configure an APN for each machine. ;) > > Ideally, we try to use a single configuration for the entire fleet to kee= p the > fleet easy to manage. But for a variety of business and technical reason= s, > 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 b= e 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 tha= t this > will be the case with the majority of devices and/or providers. On the o= ther > 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 mecha= nism > for specifying the APN policy for a particular fleet. (At least in theor= y 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 eno= ugh to > accommodate the needs of most fleets (probably using a provider -> APN m= apping, > assuming we can guess the provider e.g. using the mobile-broadband-provid= er-info > database). I'm getting lost, why is the default mobile-broadband-provider-info = plugin not good enough? And why don't you simply create your own = database based on the providers you are targeting? To me it seems like = you need X entries for all X providers you have. Unless the settings = vary within a given provider somehow? Regards, -Denis --===============2889421915624852583==--