What is SDN ?

Original Definition of SDN

“The physical separation of the network control plane from the

forwarding plane, where a control plane controls several

devices.”

Traditional network Model

Closed system - HW, OS, APP ( BGP,OSPF etc ) are hardly coupled and vendor specific.

1. Software cannot used on other vendor’s system
2. Have to wait vendor’s release for bug fix

Autonomous System on each BOX.

1. Different Policy can be used on different system
2. Totally different Architecture or management UI between Vendor.
3. Problem can be happened from one of system w/o notice unexpectedly
4. Difficult to upgrade OS
5. Difficult to change policy rapidly

SDN network Model

1. Controller working as Operating system and control many network elements.
2. De-coupling Control plane from Data plane
3. Open standard interface used for communication between Network OS and Network Element.
4. Vendor Independent
5. Application can be reused on other system.

What is SDN?

SDN encompasses low-level switching optimization & high-level application orchestration

Key features of SDN

1. Network Abstraction - Separation of Control and Data Planes
2. Programmable Data plane
3. Virtualization of the network
4. Automation and Orchestration
5. Innovation of new services