In the world of 5G, edge computing plays a critical role in ensuring low-latency and high-performance applications. However, with the increased mobility of users, there is a need for seamless migration of the Application Function (AF) and User Plane Function (UPF) to another edge cluster. In this use-case, we will simulate UE mobility and explore the AF and UPF migration to another edge cluster, using Aarna’s AMCOP platform In place of real UE (User Equipment) devices, we use a software simulator (UE Sim).
First, it is important to note that the 5G Core and MEC applications must be deployed in the target cluster, which can communicate with the 5GC via the NEF. Additionally, AMCOP should have at least two target clusters onboard, and the UE simulator must have a PDU session established with UPF in one of the edge clusters. All 5GC functions in this use case belong to the same PLMN.
The following diagram describes the use-case at a high level.
Assuming that the AF (and UPF) are relocated to the other edge cluster, the AF has to now initiate the following procedure in 5GC.
When the UE moves to another location, it triggers the relocation of the AF and UPF to another edge cluster. After the relocation, the AF in the source cluster calls traffic influence APIs exposed by the NEF in 5GC. The NEF should expose the following APIs at the minimum for this to occur:
The AF then uses the traffic influence API to notify the SMF in the 5GC about the change in traffic patterns. The SMF, in turn, acts upon the traffic influence rules initiated by the AF and updates the PDU session.
It is important to note that AF requests targeting an individual UE by a UE address are routed to an individual PCF using the BSF. This routing ensures that the AF can accurately identify the UE, which is necessary for proper traffic influence.
In summary, with the help of the NEF and SMF, the AF can seamlessly migrate to another edge cluster, ensuring uninterrupted service to the end-users. This use case highlights the importance of proper traffic routing and communication between 5GC functions to ensure a smooth and efficient network experience.
