Mobile Core Overload Control With Selective NAS Request Blocking
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Solution Overview
Problem
Certain terminals in 4G and 5G mobile networks fail to respect contention durations during network overload, leading to increased signaling flows and prolonged overload states in the core network, exacerbated by the rise of connected objects from various manufacturers.
Innovation Solution
A method and device at the core network entrance allocate temporary identifiers to terminals that violate contention durations, sending control messages to access points to block illicit requests, thereby filtering them before reaching the core network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If terminals reissue NAS requests before contention duration expires, then terminals can attempt to establish communication sessions more aggressively, but signaling flows increase and overload state is prolonged
Solution Approach 1:
The access network device acts as an intermediary between terminals and the core network. It monitors contention duration compliance and selectively blocks NAS requests from non-compliant terminals, preventing them from reaching the core network. This mediator role resolves the contradiction by filtering harmful requests while allowing legitimate ones to pass through.
Solution Approach 2:
The system implements feedback by monitoring whether terminals respect allocated contention durations. When non-compliance is detected, the access network device responds by blocking subsequent NAS requests from those terminals. This feedback loop prevents further aggravation of the overload state while maintaining network responsiveness to compliant terminals.
2Reliability
If the core network node rejects all NAS requests from terminals during overload, then the core network is protected from further load, but legitimate requests from compliant terminals are also blocked
Solution Approach 1:
The blocking action is applied locally and selectively to specific terminals that violate contention duration rules, rather than globally to all terminals. The access network device identifies non-compliant terminals individually and blocks only their requests, while allowing requests from compliant terminals to reach the core network. This localized approach maintains core network stability while preserving access availability for legitimate users.
Solution Approach 2:
The access network device serves as an intermediary that filters NAS requests before they reach the core network. It inspects each request, checks terminal compliance status, and selectively permits or blocks requests accordingly. This intermediary function protects the core network from non-compliant terminals while maintaining access for compliant ones.
3Loss of time
If the access network blocks requests from terminals not respecting contention duration, then signaling flows are reduced and overload recovery is accelerated, but additional monitoring and control complexity is introduced
Solution Approach 1:
The system leverages existing terminal behavior (sending NAS requests) and existing network infrastructure (access network devices already present in the architecture). The access network device uses its existing monitoring capabilities to detect contention duration violations and applies blocking based on simple compliance checks. This self-service approach accelerates recovery without requiring major architectural changes or additional complex control mechanisms.
Data Source
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AI summary
The management method is intended to be implemented by an input device on the network core and comprises, for at least one terminal connected to the mobile access network via an access point, following the receipt (E20) of an NAS request coming from the terminal: - detecting whether a contention period is associated with this terminal; - if not, associating (E40) and transmitting (E50) to the terminal a contention period to be applied for sending NAS requests to the network core. The method further comprises, if at the time of the detection it is detected that a contention time is associated with the terminal and has not been respected by same (E60), sending (E110) to the terminal, via the access point, a temporary identifier allocated to the terminal for communicating with the network core, and sending (E140), to the access point, a control message comprising at least a part of the temporary identifier, this control message requiring blocking by the access point of all or part of the requests sent by a terminal which contains said at least one part of the temporary identifier.