Your quick guide to Network Functions in 5GC
Why 5GC is different
3GPP has ended up in a potentially complex situation, where we now have two network architectures on the table. Consequently, depending on how communication service providers deploy their radio networks, which technology they use for coverage band, and which technology they use for capacity bands, they may end up with different core network solutions.
The major difference with 5G Core (5GC) compared to EPC is that 5GC’s control plane (CP) functions interact in a Service-Based Architecture (SBA). A key Network Function (NF) of SBA is the Network Repository Function (NRF), which provides NF service registration and discovery, enabling NFs to identify appropriate services in one another. SBA principles apply to interfaces between CP functions within 5GC only, so interfaces toward Radio Access Network (RAN), user equipment or user plane (UP) functions (N1, N2, N3, N4, N6 and N9) are excluded.
Another major difference in 5GC’s CP is the structure, because it has different functional separation of Access and Mobility Functions (AMF) and Session Management Functions (SMF). 5GC includes the separation of UP and CP functions of the gateway, which was an evolution of the gateway CP/UP separation (CUPS) introduced in EPC Release 14. Other changes include a separate Authentication Server (AUSF) and several new functions, such as the Network Slice Selection Function (NSSF) and the Network Exposure Function (NEF).
As we see it, service providers should only have to manage one core network, and any device should be able to access that network over any access technology. They should also have a common set of resources that can be used for serving the complete subscriber base. Finally, striving towards making operations as efficient as possible is key, while not forgetting the importance of flexibility to open up new business opportunities without bringing extensive or costly reconfigurations.
Taking a dual-mode approach to core evolution
Considering service providers’ concerns for protecting investments already made in the network, we have designed a solution, as described in Figure 1, that allows full integration of new cloud native NFs with Virtual or Physical NFs (VNFs and PNFs) in the same network, and offers different migration paths to bring all NFs into a full cloud native, dual-mode 5G Core over time. This makes deployment more flexible, allows for interworking with legacy networks and a smooth evolution to 5GC.
Our dual-mode 5G Core solution delivers cloud native applications that support both EPC and 5GC 3GPP architectures. It ensures capacity, elasticity and agnosticism to the underlying infrastructure, and high levels of orchestration and automation for operational efficiency.
For more info on our dual-mode 5G Core, download the solution description.
Want to know more about 5G Core?
Explore all of the different areas that will form the foundation of your cloud native core network for 5G. Download the complete cloud-native 5G Core guide series to learn more.
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