A transport zone is a mandatory object or container in NSX prior to creating a logical switch. A logical switch must be created on a transport zone. If you are familiar with vCenter in vSphere, it is similar to the virtual data center object concept in vCenter, where it functions as a container to place ESXi hosts, vSphere clusters, or virtual machines.

When creating a logical switch, the NSX Manager will look for the transport zone configuration to see which vSphere clusters are part of it. The NSX Manager will create the logical switch or dvPortGroup on all virtual distributed switches in that transport zone, which could be in multiple distributed switches.

Unlike other NSX objects, the transport zone ID is not shown in the vSphere web client UI. The transport zone ID is required when you want to use the NSX REST API or for troubleshooting purposes. The transport zone ID can be retrieved from the REST API or through the NSX central CLI by logging into the NSX Manager CLI and running the following command: show logical-switch list all. The format of the transport zone ID is vdnscope-<id>.

In the following example, the transport zone ID of the RegionA01_TZ transport zone is vdnscope-1: