ry Policy Configuration RAN Intelligent Controller (RIC) non-RT Orchestration & Automation (e.g. ONAP): MANO, NMS RAN Intelligent Controller (RIC) near-RT Applications Layer Third-party Radio Connection Mobility Interference Trained Model Radio-Network Information Base E2 :btw RIC near-RT and CU/DU CU-CP CU-UP Multi-RAT CU Protocol Stack PDCP-C PDCP-U NFVI Platform: Virtualization layer and COTS Platform RAN DU: RLC/MAC/PHY-high Open Front Haul RAN RRU: PHY-low/RF Figure 12.15 - The O-RAN architecture The O-RAN architecture is based on the following core principles: Open interfaces for RAN virtualization, and AI-capable Composable model for RAN to allow multi-vendor components and solutions Use of off-the-shelf silicon and hardware to minimize the need for any proprietary hardware Specification for open APIs to foster the use of open source components and adopt standards wherever possible In the previous section, we looked at O-RAN and how its core principles help to optimize 5G networks from the service provider's perspective. In the next section, we will look at the emergence of hybrid cloud and its role for 5G operators. 5G Infrastructure Design Using hybrid cloud In Chapter 3, Building Blocks - Cloud Native Infrastructure, we covered the topic of cloud-native infrastructure for 5G to drive the move from proprietary hardware to increased use of mainstream COTS products. This creates composable architecture with the ability to mix and match building blocks. These building blocks can be COTS hardware or microservices for the software stack. Figure 3.2 in Chapter 3, illustrates some of these components prevalent today. This also enhances the ability to port 5G infrastructure across different types of infrastructure building blocks. The focus on the public cloud landscape to support hybrid cloud comes in handy here. The 5G industry landscape is gradually maturing and going through Non-Standalone (NSA) and Standalone (SA) evolutionary phases. (See the document located here: https //www.t-mobile. com/content/dam/tfb