ecommunications System User Plane User-Plane Function URLLC Ultra-Reliable Low-Latency Communication UE Route Selection Policy UTRAN Universal Terrestrial Radio Access Network Vehicle-to-Everything virtualized gNB-DU VLAN identifier Virtualized Infrastructure Manager Virtual Machine virtual network function Virtual Network Index Virtual Reality VR/AR Virtual Reality and Augmented Reality virtual RAN VXLAN Virtual Extensible LAN W-AGF Wireline Access Gateway Function wide area network Wireless Broadband Alliance wavelength division multiplexing Working Group 7 WiMAX Worldwide Interoperability for Microwave Access wireless local area network xxxiv Acronyms and Abbreviations World Radiocommunication Conference digital subscriber line technologies Xn-AP Xn Application Protocol Xn Control Plane Xn User Plane Zero Touch Provisioning Introduction As a general rule of thumb, every 10 years the cellular industry introduces a new technol- ogy: 3G Universal Mobile Telecommunications Service (UMTS) circa 2000, 4G Long-Term Evolution (LTE) circa 2010, and now finally 5G in 2020. Within that evolution, every tech- nology cycle comes with advancement in terms of performance and new services, which the technology makes possible. These are typically attributed (and justifiably so) to the air interface, including the physical layer and the protocol stack. What is often overlooked is the Radio Access Network (RAN), which is fundamental to the success of every technology and which also undergoes major changes when a new technology is released. The RAN is arguably the most important component in a mobile network. At least terms of deployment and operational complexity and cost it certainly is. The air interface, including the physical layer and the protocol stack, typically draw most of the attention at least in the research community as these determine to a very large extent the performance of any wireless technology. However, when it comes to deployments, RAN is what eventually makes it possible and economically feasible (or not). 