vCloud Director uses Network Pools to create programmatically on-demand L2 networking segments for Org VDC and vApp networks. Network pools can be based on VLANs, VXLAN, port groups and legacy (deprecated) vCloud Network isolation (VCDNI) technology.
VXLAN Network Pool is recommended to be used as it scales the best. Until version 9, vCloud Director would create new VXLAN Network Pool automatically for each Provider VDC backed by NSX Transport Zone (again created automatically) scoped to cluster that belong to the particular Provider VDC. This would create multiple VXLAN network pools and potentially confusion which to use for a particular Org VDC.
In vCloud Director 9 we have the option to create our own VXLAN network pool backed by a NSX Transport Zone manually created and scoped to clusters we want to (and using any control plane mode).
Advantages of the new feature are:
- No more clutter of large amount of VXLAN network pools (if there are many Provider VDCs)
- Simpler way to use hybrid or unicast control plane modes (vCloud Director would always default to multicast before)
- Control over scope of VXLAN networks – especially useful for sharing Org VDC networks between Org VDCs from different Provider VDCs.
- Adhering to best practice of scoping transport zone to whole vDS (more here)