Multi-Access PDU Session Steering via SMF UPF Segmentation
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Solution Overview
Problem
Current 5G network technologies are limited in supporting access traffic steering, switching, and splitting (ATSSS) functions due to the inability to establish multi-access PDU sessions across multiple access networks, restricting the ability to distribute user traffic efficiently across different access networks.
Innovation Solution
A method and network entity that utilize a session management function (SMF) to transmit multi-access rules (MAR) to a user plane function (UPF) for establishing or modifying PDU sessions, including MAR identifiers, steering modes, and access forwarding actions, enabling efficient traffic distribution and transmission across multiple access networks within a multi-access PDU session.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single access PDU session is established for only one access network, then the session establishment is simple and straightforward, but user traffic cannot be transmitted through multiple access networks and ATSSS function cannot be supported
Solution Approach 1:
The patent segments the session management by separating control plane functions (SMF) from user plane functions (UPF). The SMF handles session establishment and modification with simplified logic, while the UPF is configured with specific forwarding rules for multi-access traffic distribution. This segmentation allows complex multi-access functionality without increasing control plane complexity.
Solution Approach 2:
The N4 interface acts as an intermediary between the SMF and UPF, carrying session management messages and forwarding rules. This intermediary mechanism enables the SMF to provision multi-access forwarding rules to the UPF without direct complex interaction, simplifying the session management while supporting ATSSS functions.
2Productivity
If multi-access PDU sessions are established across multiple access networks, then traffic distribution across different access networks is enabled, but the session establishment and management becomes complex
Solution Approach 1:
The patent uses parameter changes in the N4 session modification request messages to enable traffic distribution. By modifying forwarding rule parameters (adding up to 32 forwarding rules with different priorities and access network associations) in existing session management procedures, the system achieves efficient multi-access traffic distribution without fundamentally changing the session establishment process.
3Adaptability or versatility
If existing PDU session establishment procedures are used, then the procedure is simple and well-defined, but it only supports single access network and cannot support ATSSS function
Solution Approach 1:
The patent applies preliminary action by pre-configuring the UPF with multi-access forwarding rules during session establishment or modification. The SMF sends N4 session modification requests that include pre-defined forwarding rules for multiple access networks, so that when traffic arrives, the UPF can immediately distribute it across appropriate access networks without complex real-time decisions.
Solution Approach 2:
The patent makes the existing PDU session establishment procedures universal by extending them to support both single-access and multi-access scenarios. The same N4 session establishment and modification messages are used, but with enhanced forwarding rule configurations that can accommodate either SA PDU sessions or MA PDU sessions with ATSSS functionality.
Data Source
AI summary
A steering rule provision method for traffic distribution in a network and a network entity performing the same network. A session management function (SMF) may transmit a first message including a multi-access rule (MAR) to a user plane function (UPF), when establishing or modifying a packet data unit (PDU) session for ATSSS (Access Traffic Steering, Switching, and Splitting). The SMF may receive a second message that is a response message to the first message from the UPF.