Support for VDP in Neutron for Network Overlays

This is for topologies where Openstack compute nodes are connected to the external switches or fabrics. The fabric comprising of the switches support more than 4K segments. In some of these architectures network based overlay (and not host based overlay) is deployed. So, one should be able to create more than 4K networks in Openstack. But, the VLAN to be used for communication with the switches is assigned by the switches using 802.1QBG (VDP) protocol. The VM's sends .1q frames to the switches and the switches associate it to the segment (VNI in case of VXLAN).
With the current model:
1. One cannot use a type driver of VLAN because of the 4K limitation. Also a type driver of VXLAN or GRE cannot be used because that may mean host based overlay.
2. Also the programming of flows should be done after communicating the vNIC information to VDP and VDP communicates with the leaf switches and return the VLAN to be used by this VM. The Openstack module running in the compute communicate with VDP module (Opensource lldpad) running there. The VLAN is of local significance between the compute node and the switch to which it is connected.
Pls refer the doc given in the link below and the specification link for more information.

https://docs.google.com/document/d/1jZ63WU2LJArFuQjpcp54NPgugVSaWNQgy-KV8AQEOoo/edit?pli=1