Software-Defined Network (SDN)

(OBJ 3.1)

Decouples network control and forwarding functions, enabling network control to become directly programmable and the underlying infrastructure to be abstracted from applications and network services
Three Distinct Planes
- Data Plane (Forwarding Plane)
  - Responsible for handling data packets
    - Moves packets from source to destination
  - Makes decisions based on protocols like IP and Ethernet
  - Concerned with sending and receiving data
  - Example:
    - When you send an email, the data plane of your network takes responsibility of moving your email data from your device to the recipient's device
    - It does this by forwarding the data packets through switches and routers
- Control Plane
  - The brain of the network that decides where traffic is sent and is centralized in SDN
    - Centralized decision-maker in SDN
  - Dictates traffic flow across the entire network
  - Replaces traditional, distributed router control planes
  - Increases network manageability and flexibility
- Application Plane
  - Hosts all network applications that interact with the SDN controller
  - Applications instruct the controller on network management
  - Controller manipulates the network based on these instructions

Google's B4 project
- Google uses SDN to manage its data center networks.
- The B4 project allows Google to control the flow of data across its network ensuring that bandwidth is used efficiently.
AT&T's Domain 2.0 Initiative
- Aims to transform AT&Ts network into an SDN with a focus on reducing costs and increasing efficiency.
- By using SDN, AT&T can automate many of its network management tasks, reducing the need for manual intervention.