NEF Session Routing Under NAT for Accurate Roaming Identification
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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 application function (AF) requests accurately 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 enable the NEF to determine the roaming type of a session by obtaining a second address and its corresponding address domain, allowing the NEF to correctly influence the session by using the AF request. This is achieved through methods involving network elements like UPF, UDR, and SMF to obtain and process necessary identifiers and addresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If NAT translation is used to translate private IP addresses into public network addresses, then the terminal device can access the network, but the NEF cannot determine the roaming type of the session due to overlapping private addresses
Solution Approach 1:
The patent introduces the UPF (User Plane Function) as an intermediary between the NEF and the terminal device. The UPF maintains a mapping relationship between private IP addresses and public network addresses, and provides this mapping information to the NEF. This intermediary mechanism allows the NEF to accurately determine roaming types while still using NAT translation for network access.
Solution Approach 2:
The patent implements a feedback mechanism where the NEF queries the UPF for mapping information about private IP addresses. The UPF returns the corresponding public network addresses and roaming type information to the NEF, enabling accurate session identification and roaming determination based on the NAT-translated addresses.
2Device complexity
If the NEF uses only the public network address from NAT translation to process AF requests, then the request processing is simplified, but the correct session cannot be identified due to address overlapping
Solution Approach 1:
The patent performs preliminary action by having the NEF proactively query the UPF for mapping information before processing AF requests. The NEF obtains the correspondence between private and public addresses in advance, so when an AF request arrives with a public address, the NEF can immediately translate it back to the private address and identify the correct session without additional complexity during request processing.
Solution Approach 2:
The UPF serves as an intermediary that stores and provides the mapping relationship between private IP addresses and public network addresses. This intermediary maintains the necessary information to enable accurate session identification while keeping the NEF's request processing logic relatively simple.
Data Source
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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.