 Service Proxy Ingress Inter cluster Controller control traffic Egress Controller E1 SCTP /CU-UP Kafka Kafka Overload Config N3 GTPU Trace Broker and Policy Manager Producer Manager F1-U PDGP DU/CU Kubernetes Figure 6.2.7 Container-based RAN platform. A detailed RAN virtualization example, with different functions mapped to different vir- tualized platform components, is shown in Figure 6.2.7. In this example, IWFs are used to convert Stream Control Transmission Protocols (SCTP) from 3GPP into HTTP2 com- mands, which is what is typically supported within a container platform. The ingress/egress controllers manage inter-cluster communications. The container platform comes with a set of platform services. These support features such as configuration and policy enforce- ment. The applications (e.g. NFs) run on top of the platform services. The orchestrator (e.g. K8S) provides management services such as registration and discovery. Each application microservice registers itself with service proxy indicating if the microservice has visibil- ity externally to the K8S cluster. Service proxy provides application with services within the K8S cluster. The topology observer monitors the pod health and updates service proxy as needed. The IWF microservices terminate the RAN interface messages over Ethernet (SCTP/GTP) and translates to HTTP messages and vice-versa. HTTP is the native format for K8S. 6.2.6.1 gNB-DU and gNB-CU Virtualization For the purpose of illustrating RAN virtualization, we consider the NG-RAN to be imple- mented with functional splits as discussed in Chapter 4. For example, a NG-RAN with low-level split (Section 4.5) and high-level split (Section 4.2) may contain up to three net- work nodes: radio unit (RU), which consists of the radio and low PHY, connected to a DU consisting of the high-PHY, Medium Access Control (MAC), Radio Link Control (RLC), and scheduler, which in turn is connected to a 6.2 Virtualization CU where the Packet Data Convergence Protocol (PDCP), Service Data Adaptation Pro- tocol (SDAP