What is SGW-C SGW control-plane function

SGW-C (Serving Gateway Control Plane Function) Explained Technically

The SGW-C (Serving Gateway Control Plane Function) is a key element within the Control and User Plane Separation (CUPS) architecture of modern mobile networks, specifically in 4G (LTE) and 5G deployments. CUPS separates the control plane and user plane functionalities that were traditionally combined within the Serving Gateway (SGW) in earlier network architectures.

Here's a breakdown of the SGW-C's role and functionalities within the CUPS framework:

Understanding Control and User Plane Separation (CUPS):

• In traditional 4G networks, the SGW handled both control plane functions (managing UE connection setup, mobility, etc.) and user plane functions (forwarding data packets).
• CUPS introduces a separation between these functionalities, offering several benefits:
  • Improved Scalability: Control and user plane functions can be scaled independently based on network requirements. This allows for more efficient resource allocation.
  • Flexibility: Separation allows for the deployment of control plane and user plane functions on different network elements, enabling network optimization.
  • Security Enhancements: Separation potentially improves network security by isolating control plane signaling from user plane data traffic.

Role of the SGW-C:

Within the CUPS architecture, the SGW-C acts as the control plane counterpart to the Serving Gateway User Plane Function (SGW-U). It performs functionalities traditionally handled by the SGW related to user plane control:

• UE Context Management: Maintains information about UEs connected to the network, including their IP addresses, mobility state, and QoS (Quality of Service) parameters.
• Session Management: Establishes, modifies, and terminates data sessions between UEs and the network.
• Mobility Management (Control Plane): Participates in mobility procedures like handovers when a UE moves between different cells. This includes signaling with the MME (Mobility Management Entity) to update UE location and context.
• Packet Tunnel Management (Control Plane): Manages the setup, modification, and teardown of packet tunnels used for secure data transfer between the UE and the PGW (Packet Data Network Gateway) in the user plane.

Benefits of SGW-C:

• Improved Scalability and Flexibility: By separating control plane functions from user plane data forwarding, SGW-C allows for independent scaling and deployment of these functionalities based on network needs.
• Enhanced Network Efficiency: Dedicated control plane functions within the SGW-C can potentially improve control plane signaling processing efficiency.
• Potential Security Advantages: Separation of control and user plane functions might offer security benefits by isolating control plane signaling from user data traffic.

Deployment of SGW-C:

• The SGW-C can be deployed as a dedicated network element or integrated within another network function like the MME. The specific deployment approach depends on the network architecture and vendor implementation.
• The SGW-C interacts with various elements within the CUPS architecture:
  • MME: Exchanges control plane signaling for mobility management and session management procedures.
  • SGW-U: Communicates with the SGW-U to control user plane data forwarding and tunnel management.
  • PCRF (Policy Control and Charging Function): Interacts with the PCRF to obtain policy information related to UE data services and charging.

Conclusion:

The SGW-C plays a crucial role in modern mobile networks with CUPS architecture. By handling control plane functions related to user plane management, it contributes to improved scalability, flexibility, and potentially enhanced security within the network. As mobile networks evolve, the SGW-C remains a vital component for ensuring efficient and reliable user data services.