AF Relocation Coordination During UP Path Change

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Solution Overview

Problem

When UP path change triggers AF relocation, the source AF receives notification of DNAI change without the necessary traffic routing information from the SMF, leading to an unavailable target DNAI, which disrupts the coordination of UP path change and AF relocation.

Innovation Solution

The SMF transmits target DN access location information to the source AF when no DNAI is available, allowing the source AF to retrieve the target AF, and the SMF decides notification based on received N6 traffic routing details and indications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the SMF waits for traffic routing information from the target AF before notifying the source AF of DNAI change, then the target DNAI information is available for retrieval, but the AF relocation process is delayed and service continuity is affected

Engineering Contradiction:

Improvetarget DNAI information availabilityVSAvoidAF relocation timing

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The SMF performs preliminary action by storing the target DNAI information received from the target AF before the AF relocation is triggered. When the source AF needs to retrieve the target AF, the SMF already has the target DNAI information ready, eliminating the need to wait for traffic routing information exchange between target AF and SMF, thus resolving the information availability issue without delaying the relocation process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The SMF acts as an intermediary by maintaining and providing target DNAI information to the source AF independently of the traffic routing information exchange between the target AF and SMF. This decoupling allows the source AF to retrieve target AF information immediately when needed, while the target AF can send its traffic routing information to the SMF at its own pace

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the SMF notifies the source AF of DNAI change immediately without target DNAI information, then the AF relocation process can proceed without delay, but the source AF cannot retrieve the target AF due to missing target DNAI information

Engineering Contradiction:

ImproveAF relocation speedVSAvoidAF relocation success

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The SMF performs preliminary action by pre-storing the target DNAI information received from the target AF before the relocation notification is needed. This ensures that when the source AF initiates the retrieval process, the target DNAI information is already available in the SMF, guaranteeing both the speed and success of the AF relocation process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by having the target AF send its DNAI and traffic routing information to the SMF, which then makes this information available to the source AF upon request. This feedback mechanism ensures that the source AF always has access to accurate and up-to-date target AF information, maintaining relocation reliability

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12550117B2Coordination of UP path change and AF relocation

Publication Date: 2026.02.10 LENOVO (BEIJING) LTD

AI summary

Method and apparatus for AF relocation are disclosed. A method performed at an AF comprises receiving, from an SMF, target DN access location information when no DNAI of a target AF is received for DNAI change from the AF to the target AF; and retrieving the target AF according to the received target DN access location information.