UPF IP Address Continuity During 5G to 4G Handover
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Solution Overview
Problem
During handovers between fifth generation (5G) and fourth generation (4G) networks, conventional methods disrupt user applications by changing Internet Protocol (IP) addresses, leading to issues with Digital Rights Management and regulatory restrictions, causing disruptions in user experience and real-time services.
Innovation Solution
Implementing handover logic in the User Plane Function (UPF) to maintain the same IP address for network traffic across handovers by obtaining and providing network traffic from user equipment through both 5G and 4G networks, ensuring seamless IP continuity without changes in network or IP address.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional handover methods are used between 5G and 4G networks, then network handover can be completed, but IP address changes occur causing application disruptions
Solution Approach 1:
The patent introduces a Network Address Translation (NAT) function as an intermediary component in the user plane. This NAT function translates between the terminal device's IP address and the network's IP address, allowing the terminal to maintain its original IP address while roaming between 5G and 4G networks. The NAT function acts as a mediator that handles address translation transparently, preventing IP address changes during handover and ensuring application continuity.
2Ease of operation
If IP address is changed during handover, then network routing can be simplified, but user experience and real-time services are disrupted
Solution Approach 1:
The NAT function serves as an intermediary that decouples the terminal device from the network's IP addressing scheme. By introducing this translation layer, the network can perform routing operations using network-managed IP addresses while the terminal maintains its original IP address, thus preserving user experience continuity without compromising routing efficiency.
Solution Approach 2:
The patent segments the IP addressing function into two distinct parts: the terminal device retains its original IP address identification, while the network side uses a separate IP addressing scheme for routing purposes. This segmentation is achieved through the NAT function that maintains the mapping between these two address spaces, allowing independent optimization of each part without affecting the other.
3Productivity
If local breakout is used in visited network, then IP address can be assigned locally, but handover between networks causes IP address changes
Solution Approach 1:
The NAT function in the user plane acts as a persistent intermediary that maintains IP address translation consistency across different network types. When the terminal device roams between 5G and 4G networks, the NAT function ensures that the same translation rules apply, preventing IP address changes and maintaining stability while allowing local breakout functionality to operate efficiently in the visited network.
Data Source
AI summary
In one example, a User Plane Function (UPF) in a Visited Public Land Mobile Network (V-PLMN) that includes a first network and a second network obtains network traffic from user equipment via the first network. The UPF provides the network traffic obtained via the first network to a data network with an Internet Protocol (IP) address allocated to the network traffic obtained from the user equipment. In response to a handover of the user equipment from the first network to the second network, the UPF obtains the network traffic from the user equipment via the second network. The UPF provides the network traffic obtained via the second network to the data network with the IP address.