Think of today’s typical network as the road system of a large city where data packets are the traffic that flows through it.
Each intersection is controlled by a traffic officer – today’s network devices – who directs traffic by recognizing the turning signals, size, and shape of the vehicles passing through.
These officers can direct only the traffic at their intersections; they can’t gauge the overall traffic volume or see its movement across the city. This makes it difficult to control the city’s traffic patterns, to ease peak-hour traffic, or host special parades.
For such events, each officer needs to be briefed individually – in person or via radio – about how to control the traffic at his or her intersection. In spite of each officer’s best efforts, gridlock is a regular occurrence.
A software-defined network is the equivalent of a futuristic city.
Each traffic officer is replaced by a traffic light and a set of electronic vehicle counters, which are connected to a central monitoring and control board. The city’s traffic can now be instantly and centrally controlled.
In fact, it’s even possible to programme the control board to direct the traffic differently at various times of the day or to accommodate special parades via a planned route. The programme monitors traffic flow and automatically changes the traffic lights during these events to help traffic pass through the city with minimal disruption and, afterwards, returns the city’s traffic to normal.
You decide, which is better/right or worth your money/time!