The main reason for the need for a software-defined network architecture is that it is a manageable, cost-effective and adaptable new architecture. In classical network systems, routers, switches and firewalls were set up according to their needs and each system was managed separately. It was difficult to replace existing network components if the need changed and the only option was to remove the existing one and replace the higher capacity one was also a problem. In software-defined networks, software components can be customized and also configured according to requirements. This can be done independently of any hardware device, i.e. all network hardware devices can be identified by changing the software setup at deployment time.

It separates the control and data layers, which are found as a whole in infrastructures managed by software-defined networks and using traditional network architecture. Thus, it is aimed to simplify the network and management systems and to gain an autonomous structure. Where the traffic will be routed is decided by the control layer and is the brain of the network. The layer responsible for packet switching and transmission is the data layer. It separates the control and data layers, which are found as a whole in infrastructures managed by software-defined networks and using traditional network architecture. Thus, it is aimed to simplify the network and management systems and to gain an autonomous structure.

Where the traffic will be routed is decided by the control layer and is the brain of the network. The layer responsible for packet switching and transmission is the data layer.

Unlike traditional computer networks, programmable networks have advantages in terms of management approach, maintenance of networks, cost and ease of management. The benefits of Software Defined Networks are as follows;

➨ Allows physical and virtual network devices to be managed from a central controller.

➨ Helps automate network devices. It performs seamless addition and configuration of instant network services on demand flexibly.

➨Provides improvements to end users.

➨ Provides low operational Costs. Routine network management tasks can be centralized and automated, resulting in lower operational costs.

➨ Offers flexibility, scalability and efficiency compared to traditional networks.

➨ It is widely used by social networking sites (facebook, twitter, google plus etc.) and l    arge database search engines (Google, Yahoo, Ask etc.).