123380 -

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

: 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. 123380

: 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. : Handling failures of application servers that provide