/pdf/TFB_TechTarget-whitepaper_SA-NSA-5G.pdf).This is given further context by the following descriptions: The NSA 5G phase is the first phase, where a 5G New Radio (5G NR) access network is used with the existing 4G Long-Term Evolution (LTE) network core to deliver the service. The SA 5G phase involves the use of a 5G NR access network with the newly introduced 5G network core. This is important for delivering innovation use cases and the full promise of 5G to the user community. For operators, though, the maturity curve of 5G deployments calls for flexibility in infrastructure models. This is where hybrid cloud provides several opportunities to grow and tailor 5G infrastructure deployments. This is the concept of composable networks, where 5G is treated like a wireless fabric. (See: https://www.sdxcentral.com/articles/news/composable-5g-networks its-a-thing-liqid-ceo-says/2019/09/) The functional split of RAN, as shown in Figure 12.15, opens up the opportunity to use the public cloud and, when appropriate, leverage the hybrid cloud features for 5G infrastructure: Splitting Functionality in 5G Breaking the "monolith" Telco Cloud for Real-time non-real time processing in Radio Unit Centralized Unit Distributed Unit Figure 12.16 - Splitting functionality in 5G to break up monolithic architecture The communication between the Distributed Unit (DU) and Radio Unit (RU) requires low latency. The enhanced Common Public Radio Interface (eCPRI) is the emerging standard for interfaces to Using hybrid cloud connect the RU with the DU, often referred to as fronthaul, to ensure the stringent low-latency needs (sub 100 microseconds). The DU serving the RU is a one-to-many relationship, and RUs can often be far away. (See: https://www.rcrwireless.com/20200708/open_ran/open-ran- 101-ru-du-cu-reader- - forum). Next, we will look at how the telecom cloud plays a role here in adding flexibility to the 5G infrastructure. The emergence of the telecom cloud Recent years have seen an emergence of telecom clouds providing options for 5