Software Defined Network allows network administrators to customize a given network according to changing user and business needs. Software Defined Network is an emerging architecture that is dynamic, manageable and adaptable, making it ideal for high - ban dwidth, dynamic nature of today’s application. Open Networking Foundation (ONF) defines the SDN as ‘‘ the physical separation of the network control plane from the forwarding plane, and where a control plane controls several devices ’’ [1]. Basically, the SD N decouples the Control plane (CP) and the Data plane (DP) which allows flexibility and centralized flow control of the entire network as well as provides capabilities of responding rapidly to changing network conditions, business, market and end - user’s ne eds. Network intelligence is centralized in SDN controller that maintain a global view of network, which appears to applications and policy engines as a single, logical switch. The goal of Software Defined Network is to improve network control by enabling enterprises and service providers to respond quickly to changing business requirements . SDN architecture comprises of three layers or planes i.e. Infrastructure layer, Control layer, and Application layer.