Software defined networking (SDN) is a dynamic approach to computer networking that is manageable, cost-effective and flexible making it ideal for high bandwidth dynamic nature of today’s applications.
It is an umbrella term for a series of networking technology geared to give the network agility and flexibility of virtualised server and storage infrastructure of the modern data centre. The primary purpose of SDN architecture is to enable network engineers and administrators to respond quickly and efficiently to fast occurring changes in the business environment.
Some of the important features and functions of software defined networking (SDN) are as following:
Directly programmable-Network control is directly programmable because it is decoupled from forwarding functions.
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.
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.
Highly flexible-the administrator has the right to change any network switch's rules when necessary -- prioritizing, de-prioritizing or even blocking specific types of packets with a highly granular level of control. This is of utmost importance in a cloud computing multi-tenant architecture because it allows the administrator to mange traffic loads in a flexible and more efficient manner.