Software Defined Networks

SOFTWARE DEFINED NETWORKS

Software Defined Networking is an architecture where in the network control is decoupled from forwarding and is directly programmable. Network Intelligence is logically centralized in the software based SDN controllers. These controllers maintain a global view of the network. Enterprises and carriers gain vendor independent control over the entire network from a single logical point which simplifies the network design and operation. There is no longer any need to understand and process thousands of protocol standards but only accept instructions from the SDN controllers.

There are two planes the control plane and data plane

* Control Plane: Logic for controlling forwarding behavior. Example: Routing protocols

* Data Plane: Forwarding the traffic according to the control plane logic. This also sometimes known the forwarding plane.

Example: IP forwarding

The control plane and the data plane is separated so that network control can be done software enabling them to build highly flexible, scalable networks. The software of the network can also be built independently and developed rather than being dependent on the hardware. It is also easy to debug in case of any issues.

The Open Networking Foundation (ONF) is a non-profit consortium that is leading the advancement of SDN and also standardizing elements such as Open Flow Protocol. The Open Flow is one which structures the communication between the control and data planes of the network devices. Open Flow allows direct access and manipulation of the network devices like routers and switches. Open Flow is needed to move the network control out of the networking switches to a logically centralized control software. An Open Flow is similar to a set of instruction to CPU. This protocol is implemented on both sides of the network interface between the network devices and the SDN control software. It uses a predefined or dynamically defined set of rules to identify network...