Key Components:

• P-CSCF: Proxy that routes SIP messages between devices and IMS.
• S-CSCF: Manages SIP sessions and interacts with HSS (subscriber database).
• MGCF: Connects to circuit-switched networks (e.g., PSTN).

Free5GC Introduction of IP Multimedia Subsystem Part 1: https://free5gc.org/blog/20231108/20231108/

Free 5GC Introduction of IP Multimedia Subsystem Part 2: https://free5gc.org/blog/20231206/20231206/#registration-flow

Free 5GC Introduction of IP Multimedia Subsystem Part 2: https://free5gc.org/blog/20240327/20240327/