NEF Session Routing Using Address Domains in NAT Roaming

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Solution Overview

Problem

In edge computing scenarios, network exposure functions (NEFs) face challenges in determining the roaming type of sessions when network address translation (NAT) is used, leading to difficulties in processing AF requests correctly due to overlapping private addresses, especially in edge computing home routed with session breakout (HR-SBO) roaming scenarios.

Innovation Solution

The proposed solution involves a communication method and apparatus that enables NEFs to determine the roaming type of sessions by obtaining and analyzing address domains and forwarding paths through network elements like UPFs and UDRs, using identifiers and subscription information to ensure AF requests influence the correct sessions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If NAT translation is used to translate private IP addresses into public network addresses, then network address translation is achieved, but the NEF cannot determine the roaming type of the session and cannot process the AF request correctly

Engineering Contradiction:

Improvenetwork address translation capabilityVSAvoidroaming type information

Core Design Contradiction:

Quantity of substanceVSLoss of information

Solution Approach 1:

The patent introduces an intermediary mechanism (address domain information) that bridges the gap between NAT translation and roaming type determination. The address domain serves as a mediator that preserves roaming type information even when private IP addresses are translated to public addresses, allowing the NEF to correctly identify session types despite the address transformation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent moves the identification mechanism from the IP address dimension to the address domain dimension. Instead of trying to determine roaming type directly from translated public IP addresses, the system uses address domain information as an additional dimension that contains the necessary roaming type classification, thereby solving the information loss problem.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If private addresses overlap in HR-SBO roaming scenarios, then network flexibility is improved, but it becomes more difficult for the NEF to determine the roaming type of sessions

Engineering Contradiction:

Improvenetwork flexibilityVSAvoidroaming type determination difficulty

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The address domain acts as an intermediary that decouples the relationship between overlapping private addresses and roaming type determination. Even when multiple sessions use overlapping private address ranges, the address domain information provides a unique identifier that allows the NEF to correctly determine the roaming type for each session independently.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter used for roaming type determination from IP address-based identification to address domain-based identification. This parameter change allows the system to maintain network flexibility with overlapping addresses while simultaneously enabling accurate roaming type detection through the address domain parameter.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the NEF serves both roaming and non-roaming sessions, then network service coverage is improved, but the NEF cannot distinguish between session types when receiving AF requests

Engineering Contradiction:

Improvesession service coverageVSAvoidsession type identification accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The address domain serves as a mediator that enables the NEF to handle both roaming and non-roaming sessions simultaneously while maintaining accurate session type identification. The address domain information provides the necessary distinction between session types even when the NEF serves diverse session types, allowing correct routing and processing of AF requests.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20260067674A1Communication method and communication apparatus

Publication Date: 2026.03.05 HUAWEI TECH CO LTD

AI summary

This application provides a communication method and a communication apparatus. The method includes: A first NEF network element receives an AF request from an AF network element, where the AF request is used to influence a session of a terminal device, and the AF request from the AF network element includes a first address; the first NEF network element obtains a second address corresponding to the first address and an address domain corresponding to the second address; and the first NEF network element sends the AF request to a UDR network element. According to the method described in this application, when the NEF obtains the AF request, the NEF can determine a roaming type of a session corresponding to the AF request, and the AF request can be used to influence a correct session.