5G • Services
S-CSCF
Serving Call Session Control Function
Central IMS session controller maintaining subscriber registration state and executing call routing.
Technical Explanation
The S-CSCF is the heart of the IMS core. It manages user SIP registration, downloads subscriber service profiles from UDM/HSS, and routes SIP messages between calling and called parties, invoking specialized Application Servers for features like call forwarding and emergency services.
Key Functions
- Maintains SIP registration state and active subscriber session contexts
- Downloads user telephony profiles and triggers from UDM/HSS
- Executes session routing and invokes multimedia telephony application servers
Specifications
3GPP TS 23.228, TS 24.229
Interfaces
MwCx
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