A virtual switch (or vSwitch) is a software program that enables one virtual machine to communicate with another.
Similar to a physical Ethernet switch, a vSwitch directs communication on the network by inspecting packets before passing them on. VMware uses a vSwitch to work with the system.
The vSwitch contains the VMkernel (the kernel used by VMware to access the iSCSI I/O) and the service console (the console through which management activities are performed), and uses a network port group. For the system to work with VMware, the IPs configured on the VMkernel must ping to and from the nodes in the clustered system to enable communication between VMware and the system.