In the early days of cloud computing we talked a lot about how the economy of scale offered by cloud was achieved mainly through abstraction of resources. Compute, network and storage resources were abstracted and pooled together such that they could be provisioned as services on-demand.
That economy of scale ensured that the cost of using those services decreased, making them affordable for even the smallest of organizations.
In the data center, however, similar economy of scale has been difficult to achieve because the abstraction at the network layers has remained elusive. SDN has recently emerged as a front-runner in the data center as a provider of that abstraction, turning disparate network elements into a cohesive fabric of network resources, dynamically adjusted to deliver the best performance and availability to any application that might be delivered over its formerly rigid pipes.