From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============6847574801321889213==" MIME-Version: 1.0 From: Denis Kenzior Subject: Re: [PATCH] Fix gprs provisioning for some SIM (non-USIM) cards Date: Wed, 16 Oct 2013 17:35:53 -0500 Message-ID: <525F14C9.3020709@gmail.com> In-Reply-To: List-Id: To: ofono@ofono.org --===============6847574801321889213== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Hi Alfonso, >> The MNC can only be one value and that value can even change = depending on whether you're >> operating the same SIM in a 2G device or 3G device. So trying length 3 w= hen in reality it is 2 >> can and most likely will get you into trouble. > > I do not think this can happen. For a given MCC, the length of the MNC > is always the same, or at least that is the recommendation of the ITU. > The MNC in the IMSI remains the same, but the network operator MNC can = change. For example, T-Mobile used to report its 2G network MCC/MNC as = 310 26 even though its MNC is 260. Then there are countries that run = mixed 2 and 3 length MNCs... Regardless, my main point here is that without properly coded EFad data = we cannot reliably tell what MNC length to use. >> I might be convinced to default to MNC length 2 in that case >> > > I do not think this is a good idea. Taking a look the ITU database, > countries like USA, Canada, or Colombia have MNC length =3D=3D 3. > I said I might be convinced. If the phase is set and the EFad length is = 3. The SIMs from NA operators tend to omit EFad completely or populate = it properly. Still, the safest approach is that we should not report = the MNC if the SIM doesn't tell us explicitly. > As the relationship between MCC and MNC is deterministic, when we know > the MCC we can directly find out the MNC length. I agree in that > trying first length 2, then 3 is not very elegant. But if we do not do > that I see two possible solutions: It really isn't that clear cut. For example, check out MCC 405. > > 1.- Store a table statically or in a file with the correspondence > between MCC and MNC length. I foresee maintenance problems with this > approach. > > 2.- Add a function in the provision driver so we can ask for the MNC > length for a given MCC, which would be invoked when MNC length is not > found in EFad. The implementation would search in the provisioning DB: > it could return the length of the first MNC found for that MCC (it > must be the same for all networks for that MCC). > > Opinions on this? I think you're trying to solve a problem that doesn't need to be solved. = Its 2013, I've not seen 2G sims available for ages now. 3G sims = mandate EFad data to be properly populated. I really fail to see the = point, especially breaking the core to do so. Fallback to manual user provisioning and give the user a list to choose = from. Regards, -Denis --===============6847574801321889213==--