Hypervisor
A hypervisor, or virtual machine manager, is the software that manages the virtual platform and guest operating systems.
Shared network address
There are many options for a virtual machine, including shared, bridged, and private network addresses. A shared network address is not required to start a virtual machine.
Virtual switch
Like physical switches, virtual switches can be used to provide connectivity and segmentation for virtual machines. A virtual switch is not a requirement to start or use a virtual machine