The primary goal of TS 23.380 is to ensure service continuity and high availability within the IMS core network. While network nodes (like the S-CSCF, HSS, and P-CSCF) are designed for reliability, maintenance or unforeseen failures can cause data loss or corruption. This document standardizes automatic restoration procedures to minimize user impact when these events occur. 2. Core Restoration Scenarios

: Procedures for recovering the Home Subscriber Server, which acts as the central database for user identities and profiles.

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)

: 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

: 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.