External Switch Tagging (EST):
As shown in the above figure, all the VLAN tagging of packets is performed on the physical switch, which means your ESX host doesnt see any vlan tags.
- Each outbound adapter (vmnicX) is assigned to only one VLAN,
- ESXi/ESX host network adapters are connected to access ports on the physical switch.
- The portgroups connected to the virtual switch must have their VLAN ID set to 0 (if native VLAN)
Advantages of using EST is:
- Each outbound adapter is assigned to only one VLAN
- Since each outbound adapter is assigned to only one VLAN, the number of VLANs were limited to the number of physical NIC.