The following figure shows a basic configuration of vSS. We have three VMs with virtual NIC (vNIC) to connect to the VM port group (for example, VLAN 100). We have configured two VMkernel ports—one is vmk0 for management network and another is vmk1 for vMotion traffic. There are two physical uplinks, (pNIC) connects to vSS attaching more adapters to the same virtual switch and provides redundancy.
pNIC provides connectivity to the external physical network. vSS is a layer 2 switch. With vSS, it is possible to use 802.1Q VLAN tagging:
Example of vSphere standard switches