Dumb Networks, Smart Networks and SDN

It has been some time since there was any significant debate about whether next generation networks should be dumb or smart. 

The essence of the debate was whether it was better to create a flexible network, able to create and deliver new services very rapidly, using a network where control was at the edges, or whether it was better to embed intelligence in the network "in the core," some might have argued. 

As always, the debate was somewhat "religious." Also, as often happens, the debate has been superseded. The current thinking is that networks should operate in a way not envisioned when the earlier debates were happening.

Software defined networks, the new rage, retains the smart network, in the sense of control. But SDN also abstracts that control from the network. In essence, SDN is a smart network but with flexibility gained from an essentially "dumb" transport network. 

Intelligence is not so much "in the core" of the network, but at centralized points. The point is somewhat subtle. In the past, intelligence in the core meant that control was embodied in switches, routers or signaling points scattered throughout the network.

SDN centralizes control, but not using the embedded control points scattered throughout the network. Also, intelligent devices continue to operate in the network, but with their functions controlled from an essentially external and centralized controller.

The central idea is to abstract the network such that the operator can program services instead of creating static network overlays for every new service. 

All network services are moved from the network to data centers as applications on commodity or specialized hardware, depending on performance. The hoped-for advantage is a reduction of time to market from years to hours.

So the older debate about "smart or dumb networks" has in essence been transcended. Networks can be smart, but also transparent. Using SDN, the answer to "smart or dumb" is "both."