A vCloud Director external network provides an uplink interface that connects networks and virtual machines in the system to a network outside of the system, such as a VPN, a corporate intranet, or the public Internet. Only a system administrator can create an external network.

If you have more than one vCenter Server instance registered to the system, you can create multiple external networks, each backed either by a vSphere network or a tier-0 logical router.

vCloud Director supports IPv4 and IPv6 external networks.

Note: The range of IP addresses that you define when you create the external network are allocated either to an edge gateway or to the virtual machines that are connected to this network directly. Because of this, the IP addresses must not be used outside of vCloud Director.

External Networks Backed by vSphere Networks

External networks can be backed either by a single vSphere network, or by multiple vSphere networks.

  • External networks backed by a single vSphere instance.

    To provide each consumer of the external network with a non-overlapping set of IP addresses on the vSphere network, the system administrator must configure the IP ranges on the underlying VLAN manually.

  • External networks backed by multiple vSphere networks.

    An external network can be backed by multiple vSphere networks. This approach can simplify the IP address management in vCloud Director. You can modify the properties of an external network to change its network backings.

    This type of network has several constraints.

    • The network can have at most one backing vSphere network on each vCloud Director instance registered to the system.
    • Backing network switches must all be of the same type, either vSphere Distributed Switch or standard switch.

External Networks Backed by a Tier-0 Logical Router

An external network can be backed by an NSX-T Data Center tier-0 logical router.