Backup SMF Batch Session Migration for UPF Disaster Recovery
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Solution Overview
Problem
In the CU separation architecture, when the main SMF fails, the UPF cannot acquire the backup SMF and original session information, leading to session release and affecting user experience.
Innovation Solution
Implementing disaster recovery by enabling the backup SMF to perform batch session migration, reducing the total amount of messages required and avoiding network congestion, through extended PFCP interface messages like Session Set Modification Request and Session Set Modification Response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main SMF fails, then session continuity is disrupted, but implementing traditional failover requires multiple individual session migration messages causing network congestion
Solution Approach 1:
The patent merges multiple individual session migration messages into a single batch session migration message. When failover occurs, instead of sending separate PFCP session modification requests for each session, the backup SMF consolidates all session migration operations into one message containing multiple session identifiers, dramatically reducing message overhead and network congestion while ensuring session continuity
Solution Approach 2:
The patent implements preliminary action by pre-configuring backup SMF nodes and maintaining session information in advance. The backup SMF proactively stores session context data and prepares migration capabilities before failure occurs, enabling rapid failover without requiring extensive message exchange during the actual failure event
2Reliability
If individual session migration messages are sent for each session, then session continuity is maintained, but network congestion occurs due to increased message overhead
Solution Approach 1:
The patent combines multiple session migration operations into a single batch message. The PFCP session set modification request includes a list of multiple session identifiers, allowing the backup SMF to migrate numerous sessions simultaneously through one message exchange rather than multiple individual messages, thereby maintaining session continuity while preserving network efficiency
Solution Approach 2:
The patent creates a universal batch session migration message format that can handle multiple different sessions within a single message structure. This multi-functional message type serves both session migration and information transfer purposes simultaneously, reducing the total number of messages required while ensuring all sessions maintain continuity
Data Source
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AI summary
Provided are methods and related devices for implementing disaster recovery. According to a method, in a case where a main Session Management Function (SMF) fails, a backup SMF sends a first request to a User Plane Function (UPF), wherein the first request carries a node identifier (Node ID) of the main SMF, a Node ID of the backup SMF, and a Common Session endpoint Identifier List (CSIDLIST) corresponding to the backup SMF; and the first request is used for notifying the UPF that the main SMF fails and a session or sessions in the CSIDLIST corresponding to the backup SMF is/are to be taken over by the backup SMF, so that the UPF subsequently interacts with the backup SMF for the session or sessions in the CSIDLIST corresponding to the backup SMF. In this way, in a case where the main SMF fails, the UPF identifies the failed SMF and acquires the backup SMF and the original session information, so as to implement batch session migration and ensure session continuity.