nt and because most of the functionality can be implemented in software. However, as of now, there is no well-established approach to PHY (e.g. gNB-DU and/or RU) scaling in a virtu- alized environment. 6.2.7.4 Inter-Process Communication While containers with microservices enable significant flexibility and redundancy, this comes at the cost of an increased latency if a process is split among microservices. This additional overhead needs to be accounted for in the design of for example virtualized gNB-DU, with high data rates and stringent real-time requirements for HARQ. There- fore, inter-process communication can be a significant challenge in virtualized gNB implementations. 6.2.7.5 Virtualization Overhead All virtualization frameworks, that is both VMs and containers, have a certain processing overhead. The overhead is smaller in the case of containers, however it is not negligible in for example RUs and DUs, which are typically expected to be lightweight and low cost. Furthermore, the choice of packet processing engines, for example, Open Virtual Switch (OVS) Data Plane Development Kit (DPDK) versus SR-IOV, can impact CPU resource uti- lizations as well. If OVS is used, the containers talk across systems using a virtual switch that is more flexible and scalable, while with SR-IOV the packets are sent to the container directly to provide higher throughput but may impact scalability. If there are requirements for a VNF provider to support multiple platforms (e.g. both VMs and containers), there is an overhead involved in migrating applications, for example from VMs to containers. When an application is migrated to containers, there can be an additional latency overhead involved in splitting applications into multiple microservices. This latency overhead needs to be validated especially at gNB-DU where the timing is very critical. 6.2.7.6 SCTP/GTP Interface Support Most NG-RAN interfaces use SCTP (for control plane) or GTP protocol (for user plane). However, as of now all container frameworks only support HTTP.