SMF Outage Protection Through NRF-Mediated External Failover
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Solution Overview
Problem
Wireless communication networks face inefficiencies in managing Session Management Function (SMF) outages, particularly in geographically isolated areas like Puerto Rico and Hawaii, leading to service disruptions due to the lack of multiple SMFs and inefficient SMF replacement by Network Repository Functions (NRFs.
Innovation Solution
Implementing an external SMF registration with an internal Network Repository Function (NRF) to detect SMF outages and redirect network signaling to an external User Plane Function (UPF) outside the Tracking Area (TA) when an internal SMF fails, ensuring seamless data exchange through an external SMF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple SMFs are deployed in geographically isolated TAs, then service continuity during SMF outage is improved, but network cost and complexity increase
Solution Approach 1:
The NRF acts as an intermediary between the AMF and SMFs, maintaining a registry of available SMFs and automatically selecting appropriate SMFs based on current availability. This mediator approach allows service continuity without requiring each isolated TA to host multiple SMFs, thus maintaining service reliability while avoiding the complexity of deploying and managing multiple SMFs in each location.
Solution Approach 2:
The external SMF in a different TA is configured to handle session management for multiple TAs including its own TA and other isolated TAs. This multi-functionality allows a single SMF to serve multiple purposes and locations, providing service continuity during outages without requiring redundant SMF deployments in each isolated TA, thereby reducing overall network complexity.
2Reliability
If NRF replaces SMF during outage, then service disruption is reduced, but replacement efficiency is insufficient without external SMF registration
Solution Approach 1:
External SMFs are pre-registered with the NRF before any outage occurs, and the NRF maintains an updated registry of available SMFs and their supported TAs. This preliminary action ensures that when an outage happens, the NRF can immediately identify and assign a suitable replacement SMF without delay, improving both service availability and replacement efficiency.
3Ease of operation
If internal SMF is used, then local service management is optimized, but service continuity is compromised during SMF outage
Solution Approach 1:
The system dynamically selects between internal and external SMFs based on availability. During normal operation, the internal SMF handles local service management for optimized performance. When an outage is detected, the system dynamically switches to an external SMF through the NRF's SMF selection mechanism, ensuring service continuity while maintaining ease of local management when conditions permit.
Data Source
AI summary
A wireless communication network handles Session Management Function (SMF) outage in a Tracking Area (TA). An external SMF that is outside the TA registers with an internal Network Repository Function (NRF) that is inside in the TA. The internal NRF detects the SMF outage for an internal SMF inside the TA. The internal NRF receives an SMF request from an internal Access and Mobility Management Function (AMF) inside the TA. In response to the SMF outage, the internal NRF transfers an SMF response to the internal AMF that indicates the external SMF. The external SMF receives network signaling from the internal AMF and responsively directs an external User Plane Function (UPF) that is outside the TA to exchange user data with internal wireless access nodes that are inside the TA.