An argument could be made that the hottest acronym in the networking business is SDN. It's not hard to see why when you look at the basic premise of software-defined networking: namely, to decouple the control plane and the data plane (or packet forwarding plane), logically centralize network intelligence and state, and abstract the underlying network infrastructure from the applications. The end result is a flexible, programmable and open network that reduces both capex (by optimizing network resources and hardware) and opex (via more automated functionality), streamlines service creation and fosters innovative applications and services.
Much of the work on SDN has focused on networking equipment within data centers, particularly via the Open Networking Foundation (ONF), which has been developing and standardizing a specific protocol called OpenFlow to serve as the interface between the control and data planes.
But the SDN story is by no means going to be limited to data centers - its destiny lies within carrier networks as well. A number of network equipment vendors have been looking at ways to give telecom networks not only the capex/opex benefits of SDN technology, but also an inherent multi-layer, service-oriented architecture on which to roll out new and differentiated services quickly and efficiently.
While most vendors agree that telecoms networks will be software-defined, much of the work to date has been proprietary, which arguably goes against the spirit of SDN's "open network" approach. But two significant developments in recent months have put the telecoms sector on track to bring SDN to carrier networks.
The first involves bringing SDN to the optical transport layer in part by developing extensions for OpenFlow. And the second is the creation of a new development group by Tier 1 carriers to develop network functions virtualization (NFV), which embraces the SDN concept with the aim of, as the name implies, virtualizing network functionality across hardware appliances.