SMF Failover Routing Using TAC Transfer and AMF Cache Reset
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Solution Overview
Problem
Existing telecommunications networks lack an effective mechanism to reroute network function traffic when a critical network node, such as a Session Management Function (SMF), becomes inoperable due to disasters or failures, leading to service disruptions for connected devices.
Innovation Solution
Implement a rerouting control mechanism that determines the inoperability of a network node associated with an SMF, retrieves a list of tracking area codes (TACs) corresponding to serviced network components, and transfers these TACs to a secondary SMF instance, causing the AMF to clear its cache and reroute traffic to the operational SMF instance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single SMF instance is used for session management, then device complexity is reduced, but reliability deteriorates when the SMF becomes inoperable
Solution Approach 1:
The patent implements a backup SMF instance that maintains a copy of the TAC-to-SMF mapping cache. When the primary SMF fails, the backup SMF can take over and continue providing session management services, ensuring reliability without significantly increasing operational complexity
Solution Approach 2:
The backup SMF pre-fetches and caches TAC information in advance before it is actually needed for failover. This preliminary action ensures that when the primary SMF fails, the backup can immediately start routing traffic without delay, resolving the contradiction between simplicity and reliability
2Speed
If TAC information is cached in the AMF for fast routing, then service speed is improved, but reliability worsens when the cached information becomes outdated due to SMF failure
Solution Approach 1:
The system implements a feedback mechanism where the backup SMF monitors the operational status of the primary SMF. When the primary SMF is determined to be inoperable, the backup SMF sends a notification to the AMF to clear its outdated cache, ensuring routing accuracy is maintained while preserving the speed benefits of caching
Solution Approach 2:
The routing system transitions from a static cached state to a dynamic update state based on SMF operational conditions. The AMF cache is dynamically cleared when SMF failure is detected, allowing the system to adapt between fast routing (cached state) and reliable routing (updated state) based on real-time network conditions
3Reliability
If backup SMF instances are deployed for redundancy, then reliability is improved, but device complexity increases
Solution Approach 1:
The backup SMF performs preliminary caching of TAC information in advance, so that when failover is needed, the transition can occur immediately without complex real-time data synchronization. This reduces the operational complexity of managing backup instances while maintaining reliability
Solution Approach 2:
The patent extracts the critical TAC-to-SMF mapping information from the primary SMF and places it in the backup SMF's cache before failover occurs. This extraction allows the backup to function independently with minimal complexity, as it only needs to maintain this specific cached data rather than a complete copy of the primary SMF's functionality
Data Source
AI summary
Systems and methods of managing network function routing perform or comprise determining that a first network node has been rendered inoperable, wherein the first network node is associated with a first Session Management Function (SMF); retrieving a list of tracking area codes (TACs), the list of TACs corresponding to one or more network components serviced by the first network node via a second network node, wherein the second network node is associated with an Access and Mobility Management Function (AMF); transmitting the list of TACs to a third network node, wherein the third network node is associated with a second SMF; and causing the second network node to clear its cache.