A Comparison between 4G NEs (Network Elements) and 5G NFs (Network Functions)
In the early version of 4G Network Deployment, Most of the Networks were deployed by Purpose Built Hardware and tightly integrated software and they were referred to as Network Elements.
However, in later releases (R13 and Beyond), there were some efforts to disaggregate the hardware and software and introduction of vEPC, CUPS, DECOR, and eDECOR for migration toward Cloud and Cloud Native Architecture.
However, 5G adopted this architecture from day one and most of the components of 5G Core were defined either as VNFs (Virtualized Network Functions) or CNFs (Cloud Native Network Functions).
This explanation doesn’t cover some new NFs in 5G that didn’t have any equivalents in 4G e.g. NEF - Network Exposure Function (However there was a less popular equivalent named SCEF), NRF - Network Repository Function and NSSF - Network Slice Selection Function.