Some embodiments provide a method that identifies several higher level switching elements for facilitating lower level switching elements to forward packets among network hosts. The method establishes a set of tunnels among the lower level switching elements and the higher level switching elements. At least one tunnel is established between a lower level switching element and a higher level switching element. For each higher level switching element in the several higher level switching elements, the method identifies a first set of forwarding data that specifies forwarding of packets between the higher level switching element and the several lower level switching elements. For each lower level switching element in the several lower level switching elements, the method identifies a second set of forwarding data that specifies forwarding of packets between the lower level switching element, the several of network hosts, and the several higher level switching elements.