SDN across domains in the WAN – a novice look

There has been a flurry of discussion on SDN in the WAN lately, specifically, why and how. Brent Salsbury laid out a few use cases here. The why seems pretty straightforward. I do believe it will happen, however, the how is the interesting part. Admittedly, I’m a tad of a greenhorn in the SDN space, I’ve made it work in a lab, I participate as much as I can in the working groups and I attempt (poorly) to keep up.