Provider networks allow cloud administrators to create Quantum networks that map directly to physical networks in the data center. This is commonly used to give tenants direct access to a "public" network that can be used to reach the Internet. It may also be used to integrate with VLANs in the network that already have a defined meaning (e.g., allow a VM from the "marketing" department to be placed on the same VLAN as bare-metal marketing hosts in the same data center).
The provider extension allows administrators to explicitly manage the relationship between Quantum virtual networks and underlying physical mechanisms such as VLANs and tunnels. When this extension is supported, Quantum client users with administrative privileges see additional provider attributes on all virtual networks, and are able to specify these attributes in order to create provider networks.
As of the Folsom release, the provider extension is supported by the openvswitch and linuxbridge plugins. Configuration of these plugins requires familiarity with this extension.