User Plane Handover Signaling to Prevent Packet Reordering
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Solution Overview
Problem
When a terminal apparatus moves between access network devices, the user plane network element often remains unchanged, leading to increased packet transmission latency and potential loss of uplink and downlink service packets due to inefficient path switching.
Innovation Solution
Implementing a method where the target user plane network element receives indication information from the source element to manage the transmission of service packets, ensuring they are sent to the correct destination and preventing out-of-order delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal apparatus continues to access the original user plane network element after handover, then session continuity is maintained, but packet transmission latency increases
Solution Approach 1:
The source user plane network element forwards packets to the target user plane network element in advance before the terminal apparatus completes handover. This preliminary action ensures that the target element is ready to receive packets immediately after handover, reducing latency while maintaining session continuity.
Solution Approach 2:
The source user plane network element acts as an intermediary by receiving packets from the application server and forwarding them to both the terminal apparatus (original path) and the target user plane network element (new path). This mediator approach allows seamless transition without interrupting the data flow.
2Loss of time
If the transmission path is switched from the original user plane network element to a new user plane network element, then packet transmission latency is reduced, but uplink and downlink service packets are prone to be lost
Solution Approach 1:
The source user plane network element performs preliminary forwarding of packets to the target element before the switch is completed. This ensures that no packets are lost during the transition period, as the target element already has the packets ready for delivery.
Solution Approach 2:
The patent maintains continuous packet forwarding by the source user plane network element to both the original and target paths simultaneously during handover. This continuity ensures that packet delivery remains reliable throughout the transition, preventing any packet loss.
3Reliability
If the source user plane network element continues to send packets after handover, then packet delivery is maintained, but out-of-order delivery occurs
Solution Approach 1:
The target user plane network element sends feedback to the source element indicating that handover is complete and packet forwarding should stop. This feedback mechanism ensures that the source element ceases forwarding at the appropriate time, preventing out-of-order delivery while maintaining reliable packet delivery.
Solution Approach 2:
The source user plane network element forwards packets to the target element in advance but stops forwarding once notified by the target element. This controlled preliminary action ensures packets are delivered in the correct order without causing out-of-order delivery issues.
Data Source
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AI summary
This application provides a service packet transmission method and apparatus. The method includes: A target user plane network element receives a first uplink service packet from a source user plane, where the first uplink service packet is an uplink service packet received by the source user plane after the source user plane receives a second uplink service packet, and the second uplink service packet is the last uplink service packet sent by the source user plane to a source application server; the target user plane network element receives first indication information from the source user plane network element, where the first indication information is used to indicate that sending of the first uplink service packet by the source user plane network element ends; and after the target user plane network element receives the first indication information, the target user plane network element sends, to a target AS after the first uplink service packet is sent, an uplink service packet that is sent by an access network device to the target user plane network element, so that out-of-order of uplink service packets can be avoided. This helps improve transmission performance.