The present disclosure provides an approach for scaling the number of VNFs in a data center without scaling the number of control sessions between VNFs and a data center gateway. The approach includes opening a session between a VNF and a route server, rather than between the VNF and the gateway, when the VNF needs to send its connectivity information to the gateway. The VNF sends its connectivity information to the route server, and the route server forwards the connectivity information to the gateway. The gateway receives connectivity information of a plurality of VNFs in the data center from the route server rather than from each of the VNFs individually. The connectivity information is then used to send packets, by the gateway to a VNF, for processing. The packets are sent using three layers of networking: an underlay physical network, an overlay logical network, and a second overlay logical network.