Which component must be involved in the communication between virtual machines on different physical servers?

The communication between virtual machines (VMs) located on different physical servers necessitates connectivity beyond the capabilities of just the virtual components. This is where the physical networking infrastructure plays a crucial role.

While virtual NICs allow each virtual machine to interact as if it has its own network interface, it is ultimately the physical switches and physical network cards that facilitate communication across different servers. The VMs themselves rely on these physical components to transmit data over the wider network, handling the necessary traffic routing and data transfer functions.

Hence, a physical switch is necessary to connect the different servers, and the physical network card within each server interfaces with the physical switch. The combination of these elements enables seamless communication between VMs spread across various physical hosts, making the physical components critical for inter-server VM communication.