virtual switch

In a virtualized server environment, a virtual switch is software that provides the transfer of data between VM instances within the same machine and between VM instances and the physical network. See server virtualization.

A Virtualized Server

The virtual switch enables data transfer between VM instances in the same server without resorting to leaving the server and returning. The I/O is virtualized for each VM: the virtual NICs (vNICs) emulate the network adapters.