In-Order Packet Delivery During DNAI Changes
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Solution Overview
Problem
During application relocation in edge computing scenarios, packet delivery can become out of order due to changes in Data Network Access Identifiers (DNAI), leading to challenges in ensuring end-to-end in-order delivery, especially when the old and new connections have different transport performance characteristics.
Innovation Solution
A system and method that utilizes a Session Management Function (SMF) to configure User Plane (UP) entities with flow end markers, allowing for dynamic in-order packet delivery during DNAI changes or application relocations by buffering and reordering packets appropriately, with coordination between the SMF and Application Function (AF) to manage the packet delivery process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If application relocation is performed to improve service delivery efficiency, then service delivery efficiency is improved, but packet delivery order is lost
Solution Approach 1:
The system performs preliminary actions by establishing a forwarding relationship between source and target UPFs before the DNAI change is activated. This allows packets to be smoothly transitioned from the old path to the new path without loss or reordering, as the forwarding tunnel is pre-configured and ready to receive and forward packets immediately when the relocation occurs.
Solution Approach 2:
The source UPF acts as an intermediary element during the relocation process. It maintains the old connection temporarily and forwards packets to the target UPF through a established tunnel, ensuring that packets maintain their original order even as the application relocates from source DNAI to target DNAI.
2Speed
If new connection with better transport performance is used to improve transmission speed, then transmission speed is improved, but packet arrival order is disrupted
Solution Approach 1:
The system pre-establishes a forwarding tunnel from source UPF to target UPF before switching traffic to the new connection. This preliminary setup ensures that when packets are rapidly transmitted over the new high-speed connection, they are systematically forwarded through the pre-configured tunnel, maintaining their original sequence despite the speed increase.
Solution Approach 2:
The source UPF serves as an intermediary that receives packets from the high-speed new connection and forwards them through the established tunnel to the target UPF. This intermediary mechanism ensures that even though packets travel faster over the new connection, their arrival order at the destination is preserved through systematic forwarding.
Data Source
AI summary
The present invention provides methods, apparatuses and systems supporting in-order packet delivery during application relocation or UP (User Plane) path management events such as DNAI (Data Network Access Identifier) changes. In-order packet delivery may be enforced, ensured or supported by using an indication that in-order packet delivery is requested or required for a particular traffic flow of a UE during a user plane path management event. The methods may be performed by apparatuses implementing an application function (AF), a policy control function (PCF), a session management function (SMF), or UP entities such as PDU session anchors, of the communication network, or systems implementing a combination thereof. The SMF may configure UP entities to transmit packets and flow end markers to support in-order packet delivery and provide flow end marker information to the UP entities. The UP entities may signal path changes using flow end markers.