Over the years evolving from 2G to 3G to 4G technologies, much has changed in telecommunications networks. Through it all though, one constant remained: the communications service provider (CSP) was in full control of their entire end-to-end network. Now, as we move into 5G Standalone (5G SA) architectures, you can throw that out the window.
Historically, building a telecom infrastructure was largely a question of assembling the right hardware. To deploy a 4G core network, for example, you would pick a vendor and deploy some combination of their chassis, along with all the necessary functional components. Those components—IP Multimedia Subsystem (IMS), Serving Gateway (S-GW), and many others—were physical cards, in a physical appliance, deployed in a data center that you managed and controlled.
