Policy Control Network Element Selection for 5G Session Consistency
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Solution Overview
Problem
In 5G networks, conflicts arise between policies formulated for multiple PDU sessions with the same S-NSSAI and DNN, exceeding the maximum guaranteed bandwidth or remaining usage authorized by the PCF network element, leading to subscription information inconsistencies.
Innovation Solution
A method is introduced to select a single policy control network element for multiple PDU sessions with the same S-NSSAI and DNN, ensuring consistent policy application by obtaining the identifier of the policy control network element from the binding support network element and using it for all sessions, thereby avoiding conflicts with subscription information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple PCF network elements are selected for different PDU sessions, then service diversity and load distribution are improved, but policy consistency and subscription information accuracy deteriorate
Solution Approach 1:
The patent merges the policy control function for multiple PDU sessions with the same S-NSSAI and DNN into a single PCF network element. When the SMF detects that a terminal has multiple PDU sessions with identical S-NSSAI and DNN parameters, it selects one PCF network element to serve all these sessions, ensuring unified policy management and preventing subscription information conflicts while maintaining service diversity through the same policy controller.
2Adaptability or versatility
If different SMF network elements are selected for different PDU sessions, then session management flexibility is improved, but policy coordination complexity increases
Solution Approach 1:
The patent introduces the SMF network element as an intermediary that coordinates between multiple PDU sessions and the PCF network element. The SMF detects when multiple sessions share the same S-NSSAI and DNN, and actively selects a single PCF to serve all these sessions, thereby simplifying policy coordination while preserving the flexibility of having multiple SMFs handle different session management tasks.
Data Source
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AI summary
Embodiments of this application provide a policy control method, a device, and a system, to avoid a conflict between policies formulated for a plurality of PDU sessions of a same terminal that have same S-NSSAI and a same DNN and subscription information obtained from a unified data repository network element. The method includes: sending, by a mobility management network element to a first session management network element, a first request message used to create a first session, where the first request message includes an identifier of a terminal, single network slice selection assistance information S-NSSAI, and a data network name DNN; receiving, by the first session management network element, the first request message from the mobility management network element, and sending a second request message to a binding support network element, where the second request message includes the identifier of the terminal, the S-NSSAI, and the DNN; and receiving, by the first session management network element, an identifier of a policy control network element from the binding support network element, and selecting the policy control network element based on the identifier of the policy control network element.