This document discusses the intersection of open source software and network control planes. It provides an overview of emerging open source SDN projects like OpenDaylight and RouteFlow, which is a software-defined IP routing project. RouteFlow uses an open source control plane with a Linux-based "glue" to program the data plane. The document argues that open source and SDN are accelerating the standardization of networking and that the frontier of networking is shifting from closed, vendor-led systems to ones based on APIs, open source, customer-led approaches, and network function virtualization.