Section: 4 Architecture model and concepts 4.1 General concepts
Content: The 5G System architecture is defined to support data connectivity and services enabling deployments to use techniques such as e.g. Network Function Virtualization and Software Defined Networking. The 5G System architecture shall leverage service-based interactions between Control Plane (CP) Network Functions where identified. Some key principles and concept are to: - Separate the User Plane (UP) functions from the Control Plane (CP) functions, allowing independent scalability, evolution and flexible deployments e.g. centralized location or distributed (remote) location. - Modularize the function design, e.g. to enable flexible and efficient network slicing. - Wherever applicable, define procedures (i.e. the set of interactions between network functions) as services, so that their re-use is possible. - Enable each Network Function and its Network Function Services to interact with other NF and its Network Function Services directly or indirectly via a Service Communication Proxy if required. The architecture does not preclude the use of another intermediate function to help route Control Plane messages (e.g. like a DRA). - Minimize dependencies between the Access Network (AN) and the Core Network (CN). The architecture is defined with a converged core network with a common AN - CN interface which integrates different Access Types e.g. 3GPP access and non-3GPP access. - Support a unified authentication framework. - Support "stateless" NFs, where the "compute" resource is decoupled from the "storage" resource. - Support capability exposure. - Support concurrent access to local and centralized services. To support low latency services and local access to data networks, UP functions can be deployed close to the Access Network. - Support roaming with both Home routed traffic as well as Local breakout traffic in the visited PLMN.