VMware Cloud Foundation Network Overview Video
The VMware SDDC Manager allocates cloud capacity into workload domains. Each workload domain is backed by a vSphere cluster and is managed by its own vCenter Server instance. In each workload domain, a virtual distributed switch is created with multiple VLAN-backed port groups to logically segregate and isolate the different traffic types. VMware NSX is then deployed to provide virtual networking and advanced security services
From the fine folks at VMware TV.