Prodip Sen, the network architect who's been a highly visible Verizon representative for network functions virtualization (NFV), has left the company, according to industry sources.

It's not immediately clear why he left, nor do we yet know if his departure means he'll stop being chairman of the NFV industry specifications group (ISG) within ETSI. (Verizon declined comment, as the company doesn't comment on employment issues).

The ETSI ISG — whose sixth quarterly meeting was held this week in Okinawa, Japan — was formed by the carriers that are driving NFV. In about a year and a half, they've managed to set the foundation for NFV and get the rest of the industry interested. NFV quickly became a hot topic at conferences such as Mobile World Congress, where several vendors touted plans for the virtualized evolved packet core (EPC).

While it's hard to say what Sen's departure means to Verizon, the company will at least continue to be visible when it comes to SDN and NFV topics. Victor Mendoza-Grado, a senior cloud solutions architect, is a frequent speaker at SDN-related events. And Vishnu Shukla, a principal technologist, continues to champion the idea of transport SDN and will speak on the topic at Light Reading's Big Telecom Event in June.