Research On The Control Logic Consistency Problem For Software Defined Networks

With the rapid development of Internet, a variety of application appear one by one. The expansibility, security and stability problems of the current Internet architecture have attracted more and more attention.SDN network, because of its separation of the control plane and the data plane of network, programmable features, can effectively solve the current network problems, and has been widespread concern. Because the SDN network configuration does not have the atomicity, which affects the efficiency of SDN network management, the consistency of control logic is one of the main problems of SDN, and is also a hot issue in SDN research field. The existing researches focus on solving single packet forwarding drop, packet forwarding loop, so they lack of versatile and scalable solutions. This article makes research on the consistency of the control logic during SDN network configuration update, and puts forward a consistency algorithm based on classifier and label by classifying switches and marking packets. The goal is to solve the SDN network configuration problem, guarantee per-packet consistency. The innovative completed works are as follows:(1) Aiming at the problem of inconsistency of control logic in the update process of network configuration, an abstract model is established.By analyzing the message forwarding information and network configuration information in the model, the problems are unified and summarized, and finally obtain the optimization goal of guaranteeing the consistency of control logic in the network configuration: to ensure the per-packet consistency.(2)Propose an algorithm for network configuration updating based on switch classification and message label. By combining the optimization goal and the proof of time series and logic, the per-packet consistency of every network configuration is guaranteed. Then the performance of this algorithm is compared with the existing algorithms.(3) In the Ryu controller, based on the idea of the algorithm, design and implement network configuration update module, and then combine with Mininet simulation platform to achieve configuration update algorithm. Finally through the experimental verification, verify the feasibility of the algorithm.The algorithm proposed in this paper can effectively solve the problem of packet drop, message forward loop, network policy violation,and per-packet inconsistency during the update process of network configuration. Its main advantages are as follows: (1) Reduce network configuration update time; (2) reduce the load on the controller during network configuration update; (3) reduce the need for configuration update to the network hardware and improve the efficiency of network configuration update.