In the last weeks I have been testing the support of Linphone and OpenSIPS to the RFC8599. I have managed to make everything work except for the calls in Foreground.
The process of the RFC8599 is to send a push and wait for the REGISTER before sending a new INVITE (this is necessary because the address or port could have been changed).
However, when the phone is in foreground (IOS) after receiving the PUSH notification it does not send the REGISTER, because it was not awake.
Another issue I have to workaround, is to handle three registrations after a PUSH. One I got to suppress by changing the setting of the repeat call notification to off. Because of the two REGISTERs, two INVITEs are generated and a 486 busy comes from the phone. I had to drop one of them in the proxy to make it work, but it is a horrible patch (the REGISTERs came with different call-ids).
My questions are:
Is it possible to send a REGISTER after a PUSH even in the foreground?
Is it possible to send only one REGISTER after the PUSH rather than two? I have pcaps and logs
of all the tests.
Flavio E. Goncalves