A transport zone defines the span of the virtual network, as logical switches only extend to N-VDS on the transport nodes that are attached to the transport zone. Each ESXi host has an N-VDS component for the hosts to communicate or participate in a network, they must be joined to the transport zone. There are two types of transport zones:

• Overlay – Used for all Overlay traffic for the Host TEP communication
• VLAN – Used for VLAN backed segments. This includes the Edge VM communications.
• For the Mgmt WLD, only one cluster exists. All nodes in the cluster will be added to an Overlay network. This network will be used for AVN if the feature is enabled and a VLAN backed transport zone which can be used for any VLAN-backed segments that are created in NSX-T.

Figure 22.          Mgmt WLD Transport Zones

For VI WLD transport zones, when the first cluster is added to the first VI WLD, SDDC Manager creates the Overlay and VLAN transport zones in the VI WLD. These transport zones are then used for that WLD or even another VI WLD if the same NSX-T instance is used. This is known as 1:Many or one NSX-T instance for multiple VI WLD. However, with VCF 4.0 it is now possible to create a new NSX-T instance for each VI WLD. This is known as the 1:1 NSX-T feature, one NSX-T instance for each VI WLD.

Figure 23.          VI WLD 1:Many NSX-T Transport Zones

Note: When subsequent clusters are added to a WLD, or if a new WLD is created, all the nodes participate in the same Overlay Transport Zones. For each cluster, the same VLAN or a different VLAN can be used for the Host TEP traffic for the Overlay. We recommend using different VLANs as the size of clusters and the number of clusters scale.