Today’s emerging needs (Internet of Things applications, Network Function Virtualization services, Mobile Edge computing, etc.) are challenging the classic approach of deploying a few large data centers to provide cloud services. A massively distributed Cloud-Edge architecture could better fit the requirements and constraints of these new trends by deploying on-demand infrastructure services in Point-of-Presences within backbone networks. A key feature in this context is the establishment of connectivity among several virtual infrastructure managers in charge of operating, each one, a subset of the infrastructure. After explaining the networking challenges related to distributed Cloud-Edge infrastructures, this article surveys and analyzes the characteristics and limitations of existing technologies in the field of Software Defined Network that could be used to provide the inter-site connectivity feature. This survey is concluded by discussing some research directions.