Open Source IMS client¶

This project is about the current work in progress / exploration of putting together and extending a variety of components in order to implement an open source client for IMS, specifically how it is used in VoLTE and VoWiFi.

The current work-in-progress bases around the use of modified versions of StronSWAN and doubango.

The idea is to develop this entirely on a standard GNU/Linux operating system (laptop) with a SIM card reader attached. Once that works, we can then transplant that into a target platform, such as Ubuntu Touch or any suitable Linux based smartphone OS.

Current state¶

• using the modified StrongSWAN it is possible to establish the SWu interface for VoWiFi, at least once (something preventst it from working subsequent times). Tested against T-Mobile Germany ePDG.
• using the modified doubango, it is possible to perform Initial IMS registration (SIP REGISTER dance with the associated sec-agree key handshake, etc.) against a Kamailio IMS Core.

Current areas of work¶

• SIM card interface in doubango, see #5481
• Going beyond SIP REGISTER towards testing actual IMS calls with doubango
• clean-up of current patches, making things more stable

TODO / next steps¶

• running doubango on top of strongswan for the two nested IPsec tunnels, see #5484
• testing doubango against commercial IMS operators (using Strongswan SWu or possibly a LTE modem that allows IMS default bearer establishment)

Further wiki pages¶

• AKA socket SIM interface
• Doubango
• IMS
• Kamailio IMS Core
• VoLTE
• VoNR
• VoWiFi