Overlay networks as proposed by companies such as Nicira Networks Inc. , now owned by VMware Inc. (NYSE: VMW), are “an important step, but what if you had a data center that had to serve 10,000 customers, and every customer had a complex topology? That’s the real world, and that’s not easy,” Alwan says.

via Alcatel-Lucent Has a Top-Secret SDN Startup! – IP & Convergence – Telecom News Analysis – Light Reading Service Provider IT.