Local Session Anchor Insertion for 5G Path Shortening

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Solution Overview

Problem

In 5G network architecture, there is no effective method to select an application server for a terminal device such that the path between the terminal device and the application server is the shortest.

Innovation Solution

A communication method and apparatus that trigger the insertion of a local session anchor, allowing the selection of an application server near the access point of the terminal device, thereby shortening the path between the terminal device and the application server.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a same application server is deployed in both central DC and local DC, then service availability is improved, but path length between terminal device and application server increases

Engineering Contradiction:
Improveservice availabilityVSAvoidpath length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent introduces a local session anchor (local UPF) as an intermediary between the terminal device and the application server. When a terminal device accesses a local DC, the local session anchor is inserted into the PDU session path to forward data packets locally, avoiding direct connection to the central DC application server. This intermediary mechanism maintains service availability through multiple deployment locations while minimizing path length by utilizing local routing capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If application server selection is made without local session anchor insertion, then network architecture simplicity is maintained, but communication latency increases

Engineering Contradiction:
Improvenetwork architecture complexityVSAvoidcommunication latency
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent performs preliminary action by inserting the local session anchor into the PDU session path before data transmission begins. The SMF determines the need for local session anchor insertion based on terminal device location and DN type, and establishes the local forwarding path in advance. This preliminary setup ensures that subsequent data packets can be routed through the local DC without latency, while the complexity is managed through automated SMF decision-making rather than manual configuration.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If local session anchor is inserted to shorten path, then communication efficiency is improved, but network element quantity increases

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidnetwork element quantity
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by inserting session anchor UPFs at specific locations where local DC access is beneficial, rather than uniformly throughout the network. The SMF makes intelligent decisions about where to insert local session anchors based on terminal device location, DN type (local vs. central), and service requirements. This selective insertion approach improves communication efficiency for local access scenarios while avoiding unnecessary network elements in scenarios where central DC access is appropriate, thus optimizing the balance between productivity and network element quantity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4117388B1Communication method and device
Publication Date: 2025.05.07 HUAWEI TECH CO LTD
  • EP4117388B1 patent drawingFigure 1
  • EP4117388B1 patent drawingFigure 2
  • EP4117388B1 patent drawingFigure 3

AI summary

A communication method and apparatus are provided, to trigger insertion of a local session anchor. In this way, an application server near an access point of a terminal device is selected, so that a path between the terminal device and the application server is short. An SMF sends first information to a first user plane network element, where the first information indicates the first user plane network element to send a report message to the SMF when receiving a first DNS response message that meets a first condition, and the report message includes information about an application server indicated by the first DNS response message or information about a data network corresponding to the application server. The first user plane network element sends the report message to the SMF when determining that the received first DNS response message meets the first condition. The SMF inserts the local session anchor based on the report message. In this way, in a process of discovering the application server, insertion of the local session anchor is triggered by using the first condition. Therefore, the application server near the access point of the terminal device is selected, so that the path between the terminal device and the application server is short.