123380

Restoration relies on specific signaling flows and data synchronization methods:

: These are specific Diameter protocol messages (Server-Assignment-Request and Location-Information-Request) used by the HSS and S-CSCF to update and overwrite user data during restoration events.

For further technical reading, the latest versions (such as ) are available via the ETSI Deliverable Repository . ETSI TS 123 380 V9.6.0 (2014-03) 123380

: Focused on basic IMS recovery for GSM and UMTS.

: Integrated support for LTE and 5G networks, ensuring that high-speed packet-based services remain resilient. Summary Table: Typical Restoration Nodes Role in Restoration Primary Data Stored S-CSCF Serving node; handles session control SIP proxies, Contact info, Auth info HSS Central database; restores S-CSCF data Private User Identity, Registration Sets P-CSCF Entry point; detects UE status UE local IP, Security associations Restoration relies on specific signaling flows and data

: Procedures for when a Serving-Call Session Control Function (S-CSCF) fails or loses registration data. It defines how the Home Subscriber Server (HSS) and other nodes collaborate to re-register users or restore sessions.

: During initial registration, the S-CSCF backs up critical data—such as the list of SIP proxies, contact information, and authentication schemes—to the HSS. : Integrated support for LTE and 5G networks,

: Handling failures of application servers that provide specific services (e.g., VoLTE, messaging). 3. Key Technical Mechanisms