VGT and VST

While working on Qos with mlnc_qos I saw the word VGT and VST

What is VLAN Tagging Method?

These were words I did not know, so I had to study:

Theses were: VLAN Tagging Methods

What is VLAN?

A VLAN (virtual local area network) is a logical group of workstations, servers and network devices that appear to be on the same LAN despite their geographical distribution. A VLAN allows a network of computers and users to communicate in a simulated environment as if they exist in a single LAN and are sharing a single broadcast and multicast domain. VLANs are implemented to achieve scalability, security and ease of network management and can quickly adapt to change in network requirements and relocation of workstations and server nodes.

What is VLAN Tagging?

VLAN Tagging, also known as Frame Tagging, is a method developed by Cisco to help identify packets travelling through trunk links. When an Ethernet frame traverses a trunk link, a special Virtual LAN tag is added to the frame and sent across the trunk link. As it arrives at the end of the trunk link the tag is removed and the frame is sent to the correct access link port according to the switch’s table, so that the receiving end is unaware of any Virtual LAN information.

What are the different Methods?

EST
Within EST (External Switching Tagging) VLAN tags are not handled[1]. The physical switchport is configured as an access-port and no vlan id is configured on the port-group. Traffic is sent to onto the port group without any vlan tagging occurring.

VST
Within VST (Virtual Switch Tagging) the physical switchport is configured as a trunk port. The port-group is then configured with a VLAN ID of 1-4094. Traffic is received on the vnic tagged, the VLAN tag is then removed and the traffic sent onto the corresponding port-group untagged.

VGT
Within VGT (Virtual Guest Tagging) only vlan tagged traffic is handled. The physical switchport is configured as a trunk port and the port-group is then configured with a VLAN ID of 4095 (All). Traffic is received on the vnic tagged. The traffic is then sent onto the port-group still tagged.

reference:
https://www.vmwarearena.com/vlan-tagging-vst-est-vgt-on-vmware/
https://www.fir3net.com/Virtualization/Vmware/vmware-vlan-tagging-methods-est-vst-and-vgt.html