Network Plane

Network Plane refers to the functional layers of a network architecture, each responsible for specific tasks in the operation and management of a network. These planes are essential to understanding and designing modern networks, particularly in the context of Software-Defined Networking (SDN) and traditional networking models.

Overview

A network plane is a conceptual division that separates the functions of networking into distinct areas, enabling modularity and manageability. The three primary planes in a network are:

• Control Plane: Responsible for decision-making and routing.
• Data Plane: Handles packet forwarding and actual data transmission.
• Management Plane: Oversees network monitoring, configuration, and management tasks.

In some contexts, the network planes are simplified into just two categories:

• Control and Management Plane: Combines decision-making, monitoring, and configuration.
• Data Plane: Focuses solely on packet forwarding and traffic handling.

Types of Network Planes

Data Plane

• Also known as the Forwarding Plane.
• Responsible for the actual movement of packets through the network.
• Functions include:
  • Packet forwarding.
  • Applying Access Control Lists (ACLs).
  • Quality of Service (QoS) enforcement.
• Operates at high speeds and is implemented in hardware or firmware for efficiency.

Control Plane

• Responsible for network decision-making, such as routing and traffic engineering.
• Functions include:
  • Building and maintaining routing tables.
  • Establishing paths for packet forwarding.
• Communicates with data plane to install forwarding rules.
• Implemented in software or hardware and often centralized in Software-Defined Networking (SDN) environments.

Management Plane

• Focuses on network configuration, monitoring, and administration.
• Functions include:
  • Collecting network statistics.
  • Managing devices and troubleshooting.
  • Implementing policies and updates.
• Interfaces with the control plane to enforce administrative rules.

Two-Plane Model

In simplified architectures, particularly in resource-constrained or specific SDN deployments, the three-plane model may be reduced to two planes:

• Control and Management Plane:
  • Combines the control and management functions into a single layer.
  • Decision-making, routing, monitoring, and configuration tasks are integrated.
  • Simplifies the design but may increase the complexity within this combined plane.
• Data Plane:
  • Retains its core role of packet forwarding and traffic handling.
  • Focuses on efficiency and performance without additional decision-making tasks.

This two-plane model is often used in systems where strict separation of management and control is not necessary, such as small-scale networks or certain IoT deployments.

Relationship Between Planes

In traditional networking, all planes are typically integrated within each network device. In Software-Defined Networking (SDN), the control plane is separated and centralized in an SDN controller, while the data plane remains on the devices. When using the two-plane model, the SDN controller may also integrate management functions into the control layer.

Applications

• Software-Defined Networking (SDN): Separates the control and data planes to enable dynamic and programmable networks.
• Traffic Engineering: Uses the control plane to optimize network paths based on policies.
• Network Monitoring and Troubleshooting: Relies on the management plane for operational insights.

Advantages

• Clear separation of tasks simplifies network design and troubleshooting.
• Enables scalability and flexibility in network operations.
• Facilitates the implementation of advanced features like network virtualization and dynamic traffic management.

Limitations

• Separating planes, especially in SDN, introduces latency between the control and data planes.
• Centralized control planes can create a single point of failure.
• Combining the control and management planes in the two-plane model can increase internal complexity.

See Also

• Control Plane
• Data Plane
• Management Plane
• Software-Defined Networking (SDN)
• Traffic Engineering