Service Communication Proxy SMF Selection in 5G Home Routed Mode
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Solution Overview
Problem
In 5G networks, the delegated discovery mode is inadequate for selecting session management functions (SMFs) in scenarios like home routed mode or enhanced topology of SMF and user plane function, as the Access and Mobility Management Function (AMF) cannot select and provide information about the Home Session Management Function (H-SMF) when operating in delegated discovery mode.
Innovation Solution
A method where the Service Communication Proxy (SCP) network element receives parameter information from the mobility management network element, determines if an SMF satisfies the criteria, and if not, selects and sends information about SMFs that support the Data Network Name (DNN) to the mobility management network element, enabling the selection of appropriate SMFs in home routed or enhanced topology modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the AMF operates in delegated discovery mode, then the service discovery function is performed by the SCP instead of the AMF, but the AMF cannot select and provide information about the H-SMF in home routed mode or enhanced topology mode
Solution Approach 1:
The SCP acts as an intermediary between the AMF and the H-SMF. When the AMF operates in delegated discovery mode, the SCP receives the service request, performs SMF discovery by querying the NRF using DNN and UE location information, and returns the discovered H-SMF information to the AMF. This mediator approach allows the AMF to benefit from delegated discovery while still obtaining necessary H-SMF selection information through the SCP's intermediary function.
2Reliability
If the AMF selects the H-SMF in home routed mode, then the H-SMF information can be provided to the V-SMF, but the AMF cannot select SMF when working in delegated discovery mode
Solution Approach 1:
The SMF selection process is segmented into distinct functional parts: the AMF provides UE location information and DNN to the SCP, the SCP performs the actual SMF discovery by querying the NRF, and the SCP returns the discovered H-SMF information to the AMF. This segmentation allows the AMF to maintain its discovery automation while the SCP handles the specific SMF selection task, resolving the contradiction between automated operation and selection accuracy.
Solution Approach 2:
The SCP serves as a mediator that bridges the AMF's automated discovery capability with the need for accurate H-SMF selection. The SCP receives parameters from the AMF, performs the discovery function by querying the NRF, and returns results to the AMF, enabling both automated operation and reliable SMF selection to coexist.
Data Source
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AI summary
This application provides a method and an apparatus for selecting a session management network element. A service communication proxy network element may determine whether there is a session management network element that satisfies first parameter information, where the first parameter information includes UE location information and a data network name DNN. When there is no session management network element that satisfies the first parameter information, the service communication proxy network element selects one or more first session management network elements that support the DNN, and sends a reject message to the mobility management network element, where the reject message includes information about the one or more first session management network elements, so that the mobility management network element may obtain the information about the one or more first session management network elements, and support to select a session management network element in a home routed mode or an enhanced topology mode.