123380 Online

: Focused on basic IMS recovery for GSM and UMTS.

: 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

The specification covers several critical failure and recovery scenarios across the IMS domain: : Focused on basic IMS recovery for GSM and UMTS

Restoration relies on specific signaling flows and data synchronization methods: While network nodes (like the S-CSCF, HSS, and

: 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.

: 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.

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