s are in various stages of virtualized RAN deployments, depending on their vendors and ability to update their system rapidly. At least one "green field" oper- ator is moving directly to a stage 4 cloud native platform, while most operators are at stage 1 for their RAN deployments as of 2019 but are rapidly moving to stages 4 and 5. 6.2.6 RAN Virtualization Platform Before discussing how various split NG-RAN functions can be mapped to virtualization platform components we illustrate (Figure 6.2.6) the virtualization platform itself. A RAN platform consists of hardware and software components that provide computing, networking, and storage capabilities to execute the NG-RAN functions. There are two types of functions - network functions (NFs), which run various parts of the protocol stack, and interworking functions (IWFs), which are used to communicate between the NFs and also with the external world. Where possible, standardized and open application programming interfaces (APIs) are used to communicate internally and externally to allow for multi-vendor support for the operators. As we show below, some NG-RAN functions can be implemented in software running on general purpose hardware, some functions are offloaded to hardware accelerators and/or graphic processing units (GPUs), some use FPGAs, and some use custom application-specific integrated circuit (ASIC). Generally, a RAN virtualization platform needs to enable the following: Decoupling of hardware and software with acceleration as needed; Scaling of the solution and resource usage with workload; Support for various functional splits and deployment options in the RAN; Lifecycle management and network automation; Support for timing and synchronization in the RAN; High availability and redundancy in the network; A common platform that can be shared with the core network for edge applications. OS Kernel Orchestrator 11111 Ethernet Figure 6.2.6 RAN virtualization platform. 6 Enabling Technologies F1-C, SCTP Registration Discovery Topology Observer DU/CU N2 SCTP