I-SMF Event Subscription Management in 5G Core Networks
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Solution Overview
Problem
The 5G mobile communication network lacks mechanisms to handle session continuity and event management when an intermediate Session Management Function (I-SMF) is inserted between the Access and Mobility Management Function (AMF) and one or more Session Management Functions (SMFs), particularly in managing already subscribed-to events.
Innovation Solution
The introduction of an intermediate-session management function (I-SMF) that enables event notification and subscription management between the AMF and SMFs, including creating a Notification Correlation ID, Subscription Correlation ID, and updating identification information to ensure seamless session management and event handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an I-SMF is inserted between AMF and SMF to maintain session continuity, then session continuity is improved, but event subscription management complexity increases
Solution Approach 1:
The I-SMF acts as an intermediary component inserted between the AMF and SMF. It receives session management requests from the AMF, forwards them to the SMF, and maintains event subscription relationships. This intermediary structure allows session continuity to be preserved during SMF changes while the I-SMF handles the complexity of event subscription management, isolating the complexity within a dedicated component.
Solution Approach 2:
The event subscription management functionality is segmented and transferred to the I-SMF. Instead of the AMF directly managing event subscriptions with the SMF, the I-SMF takes over this management responsibility. This segmentation allows the core network to maintain session continuity while the I-SMF independently handles the complex event subscription lifecycle, including creating correlations and managing subscriptions.
2Measurement precision
If I-SMF manages event subscriptions directly, then event notification accuracy is improved, but information management overhead increases
Solution Approach 1:
The I-SMF creates correlation copies of event subscription information. When the AMF needs to notify events related to SMF sessions, the I-SMF maintains correlation identifiers that copy the essential subscription information. This copying mechanism allows accurate event notification routing without the I-SMF needing to store complete subscription details, reducing information management overhead while maintaining notification accuracy.
3Measurement precision
If multiple identification parameters are created for event subscriptions, then event routing precision is improved, but device complexity increases
Solution Approach 1:
The I-SMF serves as an intermediary that manages multiple identification parameters for event subscriptions. It creates and maintains Subscription Correlation IDs and Notification Correlation IDs as distinct identification layers. The I-SMF handles the complexity of managing these multiple identifiers, using them to precisely route events between AMF, I-SMF, and SMF components while isolating the identification management complexity within the I-SMF itself.
Data Source
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AI summary
According to some aspects, devices and methods for managing communications after insertion of an intermediate-session management function (I-SMF) to communicate between an access and mobility management function (AMF) and one or more session management functions (SMFs)in the control plane of a 5G infrastructure are provided, including receiving a session request, including an SMF information, from the AMF, and forwarding the session request to at least one SMF; receiving a response to the session request from the at least one SMF, the response including a first subscription information for at least one event subscription, and creating a first identification based on the first subscription information; and transmitting, the first identification to the AMF to trigger the AMF to change an address for the at least one event subscription from the at least one SMF to the I-SMF.