The core network is the most important domain in the mobile network starting from 2G and 3G while the MSC and SGSN are the main functions there to EPC or Evolved packet Core, then EPC+ in 4G network and finally 5GC or 5G Core in 5G Network.
However, there are many differences between EPC, EPC+, and 5GC especially in the features, upgrades and main interfaces as below
- EPC (Evolved Packet Core)
- Reference Point Interfaces, Sx interfaces.
- Proprietary protocol like Diameter,S1AP,eGTP for each interface.
- Possibility of deploying DECOR.
- Some Nodes/NFs should be upgraded prior to 5G NSA Deployment.
- EPC+
- Reference Point Interfaces, Sx interfaces including Sxa, Sxb, and Sxc depending on CUPS.
- Proprietary protocol like Diameter,S1AP,eGTP-C,eGTP-U for each interface.
- Possibility of deploying DECOR.
- Some Nodes/NFs should be upgraded prior to 5G NSA Deployment.
- 5GC (5G Core)
- Service-based interfaces for CP function group (Nsmf, Namf..etc) using HTTP/2 based REST APIs.
- Reference point interfaces for UP NFs and their interconnections ( e.g. N1, N2, N4, and N9) using proprietary interfaces such as EPC.
Source: ITU, Online 2020