Abstract:  It’s difficult for mobile Ad Hoc networks based on traditional distributed networking to meet the high requirements of  complex business demand for network QoS and security. The proposal of SD-MANET, which is designed for the mobile Ad Hoc networks based on software defined network, provides an effective solution to this problem. In SD-MANET, topology discovery is a prerequisite for controller to perform traffic scheduling and security control. This paper proposed a topology discovery method for SD-MANET. The main idea is to use  connected dominating set algorithm to generate the backbone network in which backbone nodes report local topology information to the controller through the uplink path, then the controller calculates the whole network topology based on the collected neighbor information. This method reduces the extra overhead during the process of topology information by limiting the number of nodes which is responsible for reporting local topology information to controller. Simulation results illustrate that, this method can accurately generate and maintain the network topology with a less control overhead.

Key words: mobile Ad hoc networks, software-defined network, topology discovery, backbone network