Your VMware Cloud on AWS SDDC uses networking backed by either VMware NSX® for vSphere® or VMware NSX-T™. The networking configuration steps and capabilities differ between these two versions.
You can determine which type of networking your SDDC uses by logging into the VMC Console, and clicking on the card for the SDDC.
If there is a Network tab present as shown below, the SDDC uses NSX for vSphere.
If there is a Networking & Security tab present as shown below, the SDDC uses NSX-T.