In a SDDC all infrastructure is virtualized and the control of the datacenter is automated by software. vSphere is the foundation of the SDDC.
All the resources are abstracted into files and the datacenter benefits of virtualization at all levels of the infrastructure, independent of the physical infrastructure.
vSphere is the foundation for the technology that supports shared and configurable resource pools and separates the workload from the physical hardware. vCloud is a set of software tools with an integrated installer. It brings a simple path to the hybrid cloud by using common infrastructure and a consistent operational model for on-premises and off-premises data centers.