Anybody aware of a particular Samsung 4G phone that has VoLTE functionality, works on the main providers but does not on a MVNO?
I have been pondering why VoLTE devices are not working on some providers and it will be a shame if these devices are discarded earlier to the skip. 2G and 3G phone usage is a lot less now with most 3G being 4G devices dropping back. Those on THREE can change their provider for 2G (while it lasts) but those that want calls and data it will be a new phone prematurely. If 4G and VoLTE doesn't work on your provider, then move provider to one where it does.
Why Samsung? (Someone like Gavin can put me straight).
For another project I happened to buy a cheap generic 8" tablet (dual SIM CAT7) so decided to test it out for this issue. No problems at all so far regarding 4G calling and will try on more MVNO SIMs if I get the chance.
In my view it demonstrates that the networks aren't simply discriminating between devices, (particularly my scepticism regarding those sold by them), but that even an unknown generic product with VoLTE can connect correctly.
Therefore, this indicates to me that it may simply be something within the IMS interaction and/or the HSS/UDM data held and how that is being updated. I don't know whether MVNOs maintain their own or interface to the carrier. But data interface delays make sense when some MVNOs say it may take time to become effective or its omission may be down to data errors.
All good news of course if it is just data as MVNOs hopefully can revert to an allow all VoLTE policy or address it as we move forward to the same type of issues with VoNR.
The reason I am seeking a non-working VoLTE Samsung is I think I have found a way to dump the IMS log and possibly support my theory.