NSSF-Triggered NSSAI Availability Updates for AMF Data Freshness
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Solution Overview
Problem
The network slice selection assistance information (NSSAI) availability database at the network slice selection function (NSSF) may become empty or outdated in dynamically changing 5G networks, leading to service disruptions without a defined mechanism for AMFs to update their information.
Innovation Solution
The NSSF triggers AMFs to re-trigger NSSAIAvailability update service requests by sending error responses with custom headers, prompting AMFs to update their NSSAI availability information, ensuring the database is rebuilt and maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the NSSF maintains an NSSAI availability database without a defined update mechanism, then the database structure is simple, but the database becomes empty or outdated leading to service disruptions
Solution Approach 1:
The NSSF automatically triggers NSSAIAvailability update service requests to AMFs when the database is determined to be empty or outdated. This self-service mechanism eliminates the need for external management intervention while maintaining database reliability through automated self-diagnosis and self-correction.
Solution Approach 2:
The NSSF implements a feedback loop where it monitors the state of its NSSAI availability database, detects when information is missing or outdated, and automatically initiates update requests to AMFs. This closed-loop feedback system ensures continuous database maintenance without adding complex external management infrastructure.
2Loss of information
If the NSSF automatically triggers update requests to AMFs, then the database remains up-to-date, but the system complexity increases with automated triggering mechanisms
Solution Approach 1:
The NSSF performs self-diagnosis to determine whether its NSSAI availability database is empty or outdated, and automatically generates and sends trigger messages to AMFs without external intervention. This self-service approach minimizes system complexity by using existing NSSF capabilities rather than adding separate monitoring and triggering systems.
Solution Approach 2:
The patent uses existing standardized service operations (NSSAIAvailability update service requests) as intermediaries to communicate between NSSF and AMFs. By leveraging established 3GPP service interfaces rather than creating proprietary communication protocols, the solution avoids adding complexity while achieving automated information updates.
3Device complexity
If error responses with custom headers are sent to trigger AMF updates, then the update mechanism is simple, but compatibility with existing standards may be compromised
Solution Approach 1:
The patent uses custom headers in error responses as intermediary carriers to convey update triggering instructions. By embedding trigger instructions within standardized error response frameworks rather than creating entirely new message types, the solution maintains compatibility with existing 3GPP service operation structures while enabling automated updating functionality.
Solution Approach 2:
The triggering instruction is extracted as a separate customizable header field within the error response message. This allows the core standardized message structure to remain unchanged for compatibility, while the extracted header provides the additional functionality needed for automated update triggering without conflicting with existing standards.
Data Source
AI summary
A method for automatically triggering network slice selection assistance information (NSSAI) availability information updates with a network slice selection function (NSSF) includes receiving, from an access and mobility management function (AMF), a service request message. The method further includes determining, that the NSSAI availability information for the AMF is not present in an NSSAI availability information database maintained by the NSSF. The method further includes sending, to the AMF, a message for triggering the AMF to update its NSSAI availability information with the NSSF, receiving, an NSSAI Availability PUT request including NSSAI availability information for the AMF, and updating, the NSSAI availability information database to include the NSSAI availability information for the AMF.