CUPS and Network Slicing In A 5G Network

Combining CUPS and Network Slicing In A 5G Network

This article will explain how CUPS and Network Slicing work together in a 5G Network. Both CUPS and Network Slicing act as key enablers to deliver 5G services like eMBB, URLLC, and mMTC.

Let’s first understand CUPS

CUPS stands for Control and User Plane Separation. In legacy mobile network, Control Plane and User Plane were tightly coupled, leading to limitations in scaling.

Control Plane handles Signalling, Session Management, Policy enforcement, and Mobility. 

User Plane takes care of processing and forwarding User data packets, which includes Video streaming, browsing data, IoT data, etc. 

CUPS in a 4G Network

In the above 4G Network, SGW-C & PGW-C form the Control Plane and SGW-U & PGW-U form the User Plane and they are implemented separately in both these planes.

CUPS decouples these planes and allows Telcos to deploy, manage, and scale the Control and User Plane functions independently based on Network & Service demands. It allows for better scalability and additional User plane nodes can be added (as needed) to handle the increasing data traffic without impacting the Control plane. 

This is quite critical in 5G Networks where diverse services have varying Network performance requirements.

Packet Forwarding Control Protocol (PFCP) is used to communicate between both planes.

CUPS in a 5G Network

Example - In a Private 5G network for a Smart factory, the Control plane manages the mobility of sensors/robots, whereas the User plane processes only the data generated by them. With CUPS, Telcos can deploy User plane functions at the Network edge, closer to sensors/robots to reduce latency without overloading the Control plane.

Note: For simplicity, I have not referred to other 5G Network functions in the above diagram. Please refer to my article for further details about 5G Service-based Architecture and various 5G Network functions.

About Network Slicing

Network Slicing allows Telcos to divide their physical 5G network into multiple virtual networks or slices. Each of these slices are optimized for specific services. This mechanism enables customized networks or slices for various verticals like Mines, Irrigation, Manufacturing, etc. on the same infrastructure.

You can define the Network Slices based on the different Service categories in 5G:-

• eMBB based Slicing: To facilitate high data throughput for services like 8K video streaming, VR/AR, etc.
• URLLC based Slicing: To enable low latency and reliable services for mission-critical applications like robotics, remote surgery, etc.
• mMTC based Slicing: To support massive numbers of low-power IoT devices like sensors, and alarms in irrigation, homes, etc.

Combining CUPS and Network Slicing

As you understood from the above explanations, though CUPS and Network Slicing serve different purposes they are quite complementary and I will explain this why in the below sections. 

Network Slicing with CUPS in a 5G Network

Note: Above is a simplified diagram to demonstrate how CUPS and Network Slicing are placed together as a concept in a 5G Network. Network Slicing can be applied to RAN, Transport, Core and Service domains. Also, 5G Core contains other network functions like NSSF, NRF, NWDAF which support slicing.

CUPS complements different Network slices by providing the flexibility of deploying, scaling and managing User plane functions separately from Control plane. 

In URLLC Network Slicing, CUPS allows deploying User plane functions at the Network edges to ensure Ultra low latency. Control plane can remain centralized for efficient Session management.

eMBB Network Slicing needs more User plane scaling for high data throughput whereas mMTC Network Slicing generates more Signalling traffic. CUPS allows independent scaling of the Control & User plane resources to ensure optimal resource utilization.

Conclusion

CUPS and Network Slicing combination form the backbone of 5G Networks by enabling Telcos to offer customized services with flexibility, scalability, latency and throughput. CUPS enables the architectural flexibility to deploy and manage Control and User planes separately and Network Slicing allows Telcos to create virtual networks or slices optimized for different 5G Service categories.

And thus, they complement each other to deliver the promises of 5G by enabling agile, flexible, scalable networks that meet the demands of the digital ecosystem.

 

Glossary: AMF (Access Management Function), SMF (Session Management Function), UPF (User Plane Function), SGW (Serving Gateway), PGW (Packet data network Gateway), CUPS (Control and User Plane Separation), UE (User Equipment), NSSF (Network Slice Selection Function), NRF (NF Repository Function), NWDAF (NetWork Data Analytics Function), eMBB (enhanced Mobile Broadband), URLLC (Ultra-Reliable Low Latency Communications), mMTC (massive Machine Type Communications)

Please use the CONTACT Form to get in touch for any training needs, consulting assignments, or other requirements. You can also connect with me via LinkedIn.