A network pool is a group of undifferentiated networks that is available for use in an organization VDC to create vApp networks and certain types of organization VDC networks.
A network pool is backed by vSphere network resources, such as VLAN IDs or port groups, by NSX Data Center for vSphere resources, or by NSX resources.
VMware Cloud Director uses network pools to create NAT-routed and internal organization VDC networks and all vApp networks. Network traffic on each network in a pool is isolated at layer 2 from all other networks.
Each organization VDC in VMware Cloud Director can have one network pool. Multiple organization VDCs can share a network pool. The network pool for an organization VDC provides the networks created to satisfy the network quota for an organization VDC.