: Nodes use indicators (often via IETF RFC 6223) to detect the availability of peers and trigger restoration if a failure is detected. 4. Evolution and Versions
Restoration relies on specific signaling flows and data synchronization methods:
: Focused on basic IMS recovery for GSM and UMTS. 123380
: 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.
: Procedures for recovering the Home Subscriber Server, which acts as the central database for user identities and profiles. : Nodes use indicators (often via IETF RFC
The specification covers several critical failure and recovery scenarios across the IMS domain:
: 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
: 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.