Cyberstudy
PDF p.166 In progress

Software Defined Networking

Open PDF at p.166 13 flashcards

Summary

PDF p.166

Software Defined Networking (SDN) abstracts network functions into three planes— management, control, and data—to simplify the configuration and management of complex networks. SDN uses APIs to implement policy decisions, enabling automated deployment and management of network resources.

In plain words

Supplementary — not from your PDF

SDN separates the network into three planes. The management plane monitors, the control plane decides (priorities, security, paths), and the data plane actually forwards traffic. A central controller applies policy. Applications talk to it through the northbound API, and it programs devices through the southbound API. NFV runs network functions such as firewalls and routers as VMs or containers.

Detailed explanation

PDF p.166
  • Infrastructure as Code (IaC)
    • Role: Facilitates configuration of physical and virtual network appliances via scripting and APIs.
    • Complexity: As networks grow, implementing policies becomes challenging.
  • Network Planes
    • Management Plane
      • Function: Monitors traffic conditions and network status.
    • Control Plane
      • Function: Makes decisions on traffic prioritization, security, and switching.
    • Data Plane
      • Function: Handles traffic switching, routing, and security access controls.
  • SDN Applications
    • Policy Decisions: Defined on the control plane.
    • Implementation: Carried out on the data plane by a network controller application.
    • APIs
      • Northbound API: Interface between SDN applications and the SDN controller.
      • Southbound API: Interface between the controller and network devices.
  • Network Functions Virtualization (NFV)
    • Definition: Supports rapid deployment of virtual networking using general-purpose VMs and containers.
    • Benefits: Simplifies configuration, allows automated deployment of network links, appliances, and servers.

Important terms

taken from the text above
Policy Decisions
Defined on the control plane.
Northbound API
Interface between SDN applications and the SDN controller.
Southbound API
Interface between the controller and network devices.
Network Functions Virtualization (NFV)
Supports rapid deployment of virtual networking using general-purpose VMs and containers.
SDN Software Defined Networking NFV Network Functions Virtualization

Examples & real-world scenarios

Supplementary — not from your PDF
  • A controller pushing a new segmentation rule to every switch at once.
  • A virtual firewall deployed as a VM (NFV).
  • An orchestration tool using the northbound API to request a network path.

Scenario

A data centre needs to isolate a newly compromised VM immediately. With SDN, one policy change at the controller is pushed to the data plane everywhere, with no device-by-device work.

Common mistakes

Supplementary — not from your PDF
  • Swapping northbound (apps to controller) and southbound (controller to devices) APIs.
  • Mixing up the control plane (decisions) and the data plane (forwarding).

Practical skills

Supplementary — not from your PDF
  • Name the three SDN planes and the two controller APIs.

What I should remember

Key Points PDF p.166
  • IaC
    • Configuration: Physical and virtual appliances via scripting/APIs.
    • Complex Networks: Challenging policy implementation.
  • Network Planes
    • Management Plane: Monitors traffic and status.
    • Control Plane: Traffic prioritization and security decisions.
    • Data Plane: Traffic switching and security controls.
  • SDN Applications
    • Policy Decisions: Control plane.
    • Implementation: Data plane via network controller.
    • APIs: Northbound (SDN apps to controller), Southbound (controller to devices).
  • NFV
    • Virtual Networking: Using VMs and containers.
    • Automation: Simplifies deployment and management.