By: Becky Bracken

Software-defined networking (SDN) sells itself. The idea of taking hardware functions in the communications network and replacing it with inexpensive, easily updated software is appealing on its own. But separating the reality of what SDN is doing right now from the super-duper, hyped-up excitement is easier said than done.

Strategy Analytics says SDN can save mobile operators $4 billion in capital expenditures (CAPEX) by 2017. That’s a ton of dough for an industry beleaguered by the trifecta of over-the-top (OTT) competition, the “dumb pipe” conundrum and the slow crush of the global economic downturn. But beyond driving down operating costs, SDN offers flexibility and scalability, which every communications service provider (CSP) is going to need to roll out new services as quickly as the market demands them.

But ask any handful of telecom execs what they think of SDN and they’ll tell you it’s important, and each will follow up with a different definition and use case. Here’s what can be quantified: as tantalizing as this whole SDN deal sounds, there aren’t any examples of operators making SDN work in a CSP-type environment. SDN in its current state is predominantly a data-center technology that everyone is almost totally certain will translate into practical results.

Not convinced? Well, not so fast.

According to the latest SDN survey from Infonetics Research, just about every major-league operator is either evaluating SDN or plans to do so within the next three years.

SDN’s roots

SDN was born in 2005 in a thesis paper written by Stanford University students Martin Casado and Nick McKeown. Their thesis describes how to make a VNS, or virtual network system, which was simply envisioned as a cheap way for students to practice debugging parts of internet infrastructure. From Casado and McKeown’s thesis both SDN, a term not coined until 2009, and OpenFlow, the technology’s central protocol, emerged.

From the California campuses of Stanford and Berkeley, SDN graduated to the data center, where it became a useful and cost-effective tool for quickly scaling to meet demand. Today the data center is where SDN has been perfected, and where it delivers real value.

Telefónica is the CSP working the hardest on evolving SDN technology in the data center, according to NetCracker’s head of product marketing, Maria Kozlova, who says that while the data center is dominant, there are three domains where SDN is most attractive:

• the enterprise level: virtualizing equipment to offer cost savings and reduce the burden on enterprises to house and maintain network equipment;
• the data-center level: virtualizing computing for real-time scalability;
• the carrier network level: virtualizing core network functions for reduced CAPEX on hardware and increased flexibility for getting services to market.

And as SDN tallies up solid successes in the data center, carriers are looking to push the technology further up the stack.