A VMware Cloud software-defined data center (SDDC) uses a logical switching component called a Network Virtual Distributed Switch (N-VDS) or vSphere Distributed Switch (VDS) to provide layer 2 forwarding functionality [1][2]. A VDS is a network switch that provides centralized network configuration, management, and monitoring. It works with the NSX for vSphere data plane to provide layer 2 forwarding, packet filtering, and traffic monitoring services. A VDS is composed of multiple Segment Ports (which are like individual physical ports on a normal switch), Uplinks, and Transport Nodes. The Segment Ports are used to connect virtual machines to the VDS, while Uplinks are used to connect the VDS to physical networks. Transport Nodes are the physical switches that are associated with the VDS.
For more information, see the official VMware documentation here:
https://docs.vmware.com/en/VMware-NSX-Data-Center/2.4/nsx_24_sdn_networking/GUID-A4A6E4A8-FD7C-4B6E-A3D3-6F9B6D0578C2.html.