It refers to the complete separation between control plane functions and user plane functions. Control plane functions include user connection management as well as defining QoS policies, performing user authentication, etc. user plane functions include traffic forwarding, etc. The main motivation for CUPS is to make user plane functions scale independently, allowing operators for more flexible deployment and dimensioning of the network. If data traffic increases, more data plane nodes can be added without affecting the control plane functions.
CUPS also enables user plane programmability which means having a set of data plane nodes that can be selected and treated for a particular node to perform forwarding, encapsulation, traffic steering, or whatever else is needed according to the indications received by the control plane elements. A further possibility is to use the control/user plane functions split by introducing a Network Controller (NC) in the middle. Introducing a Network Controller in the mobile core architecture allows obtaining a three-tier architecture, which can be easily mapped to the software-defined networking (SDN) paradigm. SDN is composed of an Infrastructure layer, a controller layer, an Application layer. If introduced in the 5GC, the Application layer can be mapped to the control plane and the infrastructure layer to the user plane nodes.
CUPS for NG-EPC materializes scaling of the control plane and user plane independent of one another and promotes a cost-effective approach to core telecom architecture which is the network for 5G technology. It provides an adaptable and adjustable network deployment option where enhancement of control plane and user plane functionality is possible.
Benefits of CUPS
- 5G readiness: It prepares the mobile data network for 5G core network capabilities in the future.
- Gi-LAN Integration: CUPS-based EPC gateways support inline services for different SPI and DPI capabilities. One of the advantages of CUPS for USP is the ability to integrate gateway with Gi-LAN.
- Ability to mix different types of user planes: It supports a mix of different types of user planes. With this flexibility, operators can now implement specialized user planes for specialized applications.
- CAPEX and OPEX Savings: It introduces the capability to independently scale the control plane and user plane in an efficient and dynamic manner. Rapid network adjustment of resources allows operators to deliver the highest level of customer experience.
- Reducing latency on application service, e.g by selecting user plane nodes that are closer to the RAN or more appropriate for the intended UE usage type.
- Supporting increase of data traffic by enabling user plane nodes closer to the users.
- Locating and scaling the control plane and user plane resources
- Independent evolution of control plane and user plane functions
- Enabling software-defined networking to deliver user plane data more efficiently.
Cellular networks today are witnessing an increased variation in resource demands across the control planes and user planes. Some devices require high control plane resources (signaling), while other devices may require very few signaling resources but sufficient user plane and data resources. It should support:
- Large volume data support
- Rich communication services
- Customer experience and low latency
Control and user plane separation facilitates cellular operators to reduce data center costs by hosting the control plane and the user plane in different locations which can also save transmission costs.