Some embodiments provide a method of transmitting data in a logical network that includes multiple hubs in a hub cluster and multiple branches. Each branch connects to a hub of the cluster through a virtual private network (VPN) tunnel. The method is performed by a network controller. The method assigns one of the hubs as a master hub. The method then sends a command to each of the other hubs in the hub cluster to establish a VPN tunnel between the other hub and the master hub. The method then advertises, to the other hubs, routes between the other hubs through the master hub. Each branch, in some embodiments is connected to only one hub in the hub cluster.