Abstract :
Software-Defined Networking (SDN) is a new concept of network which could greatly improve the efficiency of forwarding and network management. Due to the programmability of SDN, policy will be an important part of the network. It is inevitable that there will be some policy conflicts when the network is full of mass policies. What´s more, the network equipment APIs would be always changed because of the dynamic network virtualization. So it´s necessary to deploy a policy management mechanism to enhance the network system. In this paper, we use an event assignment method to assist the policy management. Then we propose the protect time as a new concept to deal with the policy conflicts in SDN, so that we simplified the policy conflicts resolution and take full advantage of every useful policy at the same time.