An Overview of Software Defined Networking (SDN)

Software-defined networking (SDN) is a recent revolutionary concept, which aims to optimise a network’s functioning and dramatically improve its efficiency.  This is a kind of umbrella term, which covers several different types of network technology, all with the goal of making a network as flexible and agile as the virtual server, and with the storage infrastructure of the modern data centre.  With SDN, there exists a central control layer, designed for regulating the flow of information, and the attendant use of bandwidth, among other parameters.  In such a way, a SDN controller has the role of the virtual brain of the network and gives administrators a kind of bird’s eye view of it all, enabling them to respond quickly to changing business needs. This means that they are not just able to monitor traffic easily, but also direct how the network should be handled, via underlying systems such as routers, switches and other network gear.  So the network engineers can then easily respond to fluctuating business requirements and shape the flow of the traffic, without the need for individual switches.

The SDN controller is the brain at the centre and has the function of intermediary between the two levels.  The level above the controller is known as the application layer and all the data travelling towards there is designated as northbound; the level below that is called the infrastructure layer, and all data travelling there is known as southbound.  

The main benefit to adopting an SDN is that capital and operational expenses can be significantly reduced.  Through the use of optimisation strategies, automation and functional separation, significant savings in costs can also result.  It also means that greater reliability in network functioning can be achieved, and the use of programmable switches and interfaces means that easy work can be made of scaling up or down of interfaces. This is because traffic loads can be adjusted in a speedy, dynamic and cost-effective fashion.  The SDN, therefore, acts as a bridge between the network intelligence part and the physical hardware part, without any loss of efficiency or functionality.  Significant reductions are therefore made in manual administration and the time and expense involved in reconfiguration.

SDN is looking to be a godsend, at a time when existing loopholes in network technology such as complexity, vendor dependence and the inability to scale up or down speedily are giving slow growth.  The new era for IT is more cloud-centric, data-driven and application-intensive at every touch point, which means that SDN could well be the answer to progress in the future.

Picture courtesy of www.exto.com



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