Overview of Software Defined Network
A. Background of Software Defined Network:
Software defined network start off from Stanford University from its Clean State project. It was created for producing new concept of network architecture to increase the limit of the old network frames by using innovative technology, applications, and services. Control plane is separated from network hardware and it works as software.
In software defined network facilitate the network management automatically. It also controls the administration and network services of the applications. Software defined network increases the possibilities of the operating network, deploying and planning. Software defined networks increase the interest of the industry and education. So, different organization and institutes started to work on it.
In this regard Open Network Foundation presented a OpenFlow protocols which define the communications of data plane and control plane. These protocols are now the main communication interface for the software defined networks and are used widely in networks.
B- SDN Architecture
Different architecture has presented by industry and institutions to meet application requirements. But the widely used and accepted architecture is the architecture which is presented by Open Network Foundation. This architecture further divided software defined networks in layers like application, control and resource layer which is shown in the Figure below.
Software defined network is abbreviated as SDN
- Application layer: In this layer software defined networks applications specify business applications and network services and for this service aware behavior is defined. Applications are interacted with the software defined network control layer by using the application control interface and it automatically customizes properties and behavior of the network resources.
- Control layer: It controls the behavior of the network resources by dynamically that are instructed by application layer. Software defined networks tells that how the resources will be controlled with interaction to the control layer by using application control interface. Control signaling is delivered by resource control interface.
- Resource layer: Processing and transport of the data packets is performed by the network elements according to decision which is made by software defined network control layer.
- Application control interface: This interface is responsible for the communication among application and control layers.
- Resource control interface: This interface has the responsibility of the communication among resource and control layer.