On Wed, Jun 22, 2022 at 09:48:00PM -0400, Chris Talbot wrote: > Hello! > > I am trying to debug a VoLTE issue with the BM818. I am using T-Mobile USA > with VoLTE enabled on the BM818, with a Librem 5, PureOS Byzantium > (based on Debian Bullseye). > > With certain numbers, I have seen that the call terminates right after the > call is picked up. However, With the same hardware/software > set up with an AT&T MVNO (AweSIM, Purism's MVNO), I have no trouble with the > exact same number. Additionally, Calling the number with the > Pinephone Pro, VoLTE on T-Mobile USA (EG-25, MM 1.18) did not have this issue > either. > > For one number, I found that the `1-800` number had this issue (it was my > bank), but calling the same number to it's local area code > (but the same bank call system) allowed the call to complete just fine. > > I am including the log below, but the log seems to show that the other side > just terminated the call. What would be a good way to help debug/solve > this issue? >
Hi Chris, looks like the network terminated the call due to a SDP-related problem - perhaps even before the call was connected - as TLV 0x2e contains "SDP not supported". It would help if T-Mobile could provide you the corresponding SIP logs from their IMS platform for a VoLTE call with a Librem 5 phone and a Pinephone when calling that 1-800 number for comparison purposes. Checking in advance that your BM818 runs the latest firmware would help too. Regards, Reinhard
