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.

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 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. : Procedures for when a Serving-Call Session Control

The specification covers several critical failure and recovery scenarios across the IMS domain: While network nodes (like the S-CSCF, HSS, and

: Mechanisms for the Proxy-CSCF to recover its relationship with the user equipment (UE) after a restart.

: Focused on basic IMS recovery for GSM and UMTS.