Another week, another story from the SDN land, this time The Register reporting on AT&T plans. Even though there are almost no details in the story, the headline boasts that “SDN is eating vendors’ lunch”, prompting SDN hopefuls on LinkedIn groups to claim that “the promise of SDN is fast coming to fruition.”

Not so fast.

All the talk about SDN-derived cost savings is a pipe dream until SPs decide to use open-source software (or develop their own networking software like Googles of the world do). If you insist on having vendor support or single-throat-to-choke, you'll pay approximately as much as you're paying today.

Also keep in mind that SDN and NFV add (not remove) complexity, and someone is bound to pay for that - either in CapEx (financing vendor R&D) or OpEx (paying your people fixing open-source software).

Long story short: there's no free lunch regardless of what the evangelists, vendors and analysts would love you to believe.