The shift from 4G to 5G involves more than speed increases. Fifth-generation networks must accommodate diverse applications ranging from enhanced mobile broadband (eMBB) to ultra-reliable low-latency communication (URLLC) and massive machine-type communication (mMTC).

Traditional mobile architectures integrated control and user plane functions tightly, limiting scalability and adaptation to variable traffic loads. CUPS decouples these functions, enabling independent scaling and deployment flexibility—essential for delivering 5G's low-latency, high-connectivity promise.

CUPS Architecture in 5G

What is CUPS?

CUPS separates two network functions:

  • Control Plane: Manages signaling, session management, mobility, and authentication
  • User Plane: Handles actual data traffic including browsing, streaming, and calls

Previously, both planes scaled together. CUPS permits independent scaling and deployment based on specific network demands.

CUPS in 5G Core (5GC)

The 5G core employs Service-Based Architecture with modular network functions:

  • AMF (Access and Mobility Function): Controls user mobility tasks
  • SMF (Session Management Function): Manages session control and IP allocation
  • UPF (User Plane Function): Routes user data packets

CUPS enables distributing the UPF closer to users while maintaining centralized AMF and SMF functions.

Benefits of CUPS in 5G

Scalability

CUPS allows independent resource adaptation to varying traffic patterns. IoT devices require robust control-plane resources for numerous connections but generate minimal user-plane traffic. Video streaming applications demand heavy user-plane resources with limited control involvement.

Operators can:

  • Optimize resource allocation by traffic type
  • Reduce unnecessary capital and operational expenses since planes scale separately

Deployment Flexibility

User-plane functions can deploy at network edges for latency-sensitive applications like virtual reality, autonomous vehicles, and industrial automation.

This approach enables:

  • Reduced transmission delays
  • Enhanced network resilience through localized critical functions

Network Slicing

5G network slicing creates virtual networks for specific use cases. CUPS enhances slicing by allowing different control and user plane configurations per slice.

Examples include:

  • IoT slices featuring lightweight user planes with robust control capabilities
  • Streaming slices prioritizing high-throughput user planes with minimal signaling

Lower Latency and Higher Throughput

By deploying user-plane functions at multi-access edge computing (MEC) locations closer to users, CUPS minimizes data travel distance, enabling quicker response times and greater throughput for real-time gaming, AR/VR, and URLLC applications.

Cost Optimization

CUPS reduces both CAPEX and OPEX through:

  • Decoupled scaling preventing over-provisioning
  • Leveraging edge infrastructure to reduce transport costs
  • Optimizing resources for specific use cases

CUPS in Private 5G Networks

Private 5G networks serve vertical industries including manufacturing, healthcare, and logistics. CUPS enables companies to deploy user-plane functions on-premises for rapid data processing while maintaining centralized control-plane management.

In smart factory scenarios, CUPS facilitates:

  • Real-time robot-sensor communication via on-site user plane functions
  • Centralized control-plane management for seamless mobility across factory locations

CUPS and Network Automation

Combined with network function virtualization (NFV) and software-defined networking (SDN), CUPS enables dynamic network operations. SDN controllers can manage user-plane traffic dynamically, adjusting flows based on real-time conditions.

Operators can:

  • Automate traffic management with dynamic steering
  • Reduce manual intervention, improving efficiency and reducing costs

Use Cases for CUPS in 5G

IoT and Massive Device Connectivity

CUPS efficiently manages IoT networks characterized by numerous devices and low data traffic, optimizing control-plane resources for millions of connections.

Enhanced Mobile Broadband (eMBB)

For data-intensive applications like 4K streaming or immersive experiences, CUPS provides high user-plane throughput without straining control resources, enabling differentiated eMBB services.

Ultra-Reliable Low Latency Communication (URLLC)

Applications requiring ultra-low latency—autonomous driving and remote surgery—benefit from user-plane functions distributed at edge locations through MEC, minimizing delays.

Edge Computing and MEC

CUPS aligns with MEC initiatives by pushing user-plane functions to edge locations where data processes closer to users, reducing backhaul traffic and improving performance for IoT, AI applications, and real-time analytics.

Challenges and Considerations

Network Complexity

Managing separated control and user planes requires advanced automation tools and orchestration platforms utilizing cloud-native design, SDNs, and continuous integration/continuous deployment (CI/CD/CT) pipelines. Careful deployment planning ensures seamless integration with existing infrastructure.

Security Considerations

Separation introduces new security vulnerabilities. The decoupled architecture presents expanded attack surfaces requiring enhanced protective measures. Contemporary security models address these challenges through role-based access control (RBAC) within modern cloud environments.

Interoperability with Legacy Systems

Transitioning from traditional 4G to CUPS-based deployments presents challenges in hybrid networks. Operators must ensure legacy systems interoperate with new CUPS deployments without service disruption. Open RAN and more open interfaces may address such challenges in the future.

Conclusion

CUPS transforms 5G by enabling flexible, scalable, and efficient architecture supporting diverse use cases including IoT, edge computing, and private networks. Its role in delivering differentiated, cost-effective services remains critical as networks advance toward 6G.

"CUPS decouples control and user plane functions, enabling independent scaling and deployment flexibility—essential for delivering 5G's low-latency, high-connectivity promise."