EPS NAS Security Algorithm Re-Sending After Abnormal SMC
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Solution Overview
Problem
In the 5G network registration process, when a first Security Mode Command (SMC) process is normal but a second SMC process is abnormal, the User Equipment (UE) fails to obtain an Evolved Packet System Non-Access Stratum (EPS NAS) security algorithm, leading to issues like handover failure and service interruptions.
Innovation Solution
The Access and Mobility Management Function (AMF) entity re-sends the EPS NAS security algorithm to the UE after determining that the initial attempt was unsuccessful, ensuring successful configuration by using markers or updates based on completion message absence or invalidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the AMF entity sends the EPS NAS security algorithm in the initial SMC process, then the UE should receive the algorithm, but the UE may fail to receive or process it correctly due to process abnormalities
Solution Approach 1:
The AMF entity performs a preliminary check by determining whether the UE has successfully received the EPS NAS security algorithm before proceeding with normal operation. This preliminary verification action prevents subsequent handover failures and service interruptions by ensuring the algorithm is properly configured before it is needed.
Solution Approach 2:
The AMF entity implements a feedback mechanism by monitoring whether the UE has successfully received the EPS NAS security algorithm. When the algorithm delivery is detected as unsuccessful, the AMF entity triggers a re-sending action, creating a closed-loop control system that ensures reliable algorithm configuration.
2Reliability
If the AMF entity re-sends the EPS NAS security algorithm when initial delivery fails, then the UE successfully obtains the algorithm, but additional signaling messages are exchanged increasing communication overhead
Solution Approach 1:
The AMF entity applies partial action by re-sending the EPS NAS security algorithm only when the initial delivery is determined to have failed, rather than always re-sending or never re-sending. This conditional approach balances reliability improvement with minimizing unnecessary signaling overhead and time consumption.
3Reliability
If the AMF entity implements determination mechanisms to check algorithm delivery status, then delivery success is improved, but the complexity of the configuration process increases
Solution Approach 1:
The determination mechanism leverages existing completion messages that the UE sends to indicate receipt of the SMC process. The AMF entity utilizes this self-generated feedback from the UE's normal protocol behavior to verify algorithm delivery status, rather than requiring additional dedicated verification signaling, thus minimizing added complexity.
Data Source
AI summary
This application discloses methods and related apparatuses for configuring an EPS NAS security algorithm in the field of communication technologies. In an example technical solution provided in this application, an access and mobility management function entity determines whether a selected EPS NAS security algorithm has been successfully provided to a terminal device, and after determining that the selected EPS NAS security algorithm has not been successfully provided to the terminal device, the access and mobility management function entity provides the selected EPS NAS security algorithm to the terminal device again.