1. SDN

What is SDN?

The physical separation of the network control plane from the data (forwarding) plane, and where a control plane controls several devices.

What is the difference between data plane and control plane?

• Data plane refers to all the functions and processes that forward packets/frames from one interface to another.
• Control plane refers to all the functions and processes that determine which path to use. Routing protocols, spanning tree, ldp, etc are examples.

What are the characteristics of SDN architecture?

1. Directly programmable
   Network control is directly programmable because it is decoupled from forwarding functions.
2. Agile
   Abstracting control from forwarding lets administrators to dynamically adjust network-wide traffic flow to meet changing needs.
3. Centrally managed
   Network intelligence is (logically) centralized in software-based SDN controllers that maintain a global view of the network, which appears to applications and policy engines as a single, logical switch.
4. Programmatically configured
   SDN lets network managers configure, manage, secure, and optimize network resources very quickly via dynamic, automated SDN programs, which they can write themselves because the programs do not depend on proprietary software.
5. Open standards-based and vendor-neutral
   When implemented through open standards, SDN simplifies network design and operation because instructions are provided by SDN controllers instead of multiple, vendor-specific devices and protocols.