Proactive eviction of flow entry for SDN based on hidden Markov model

摘要

With the fast development of software defined network (SDN), numerous researches have been conducted for maximizing the performance of SDN. Currently, flow tables are utilized in OpenFlows witch for routing. Due to the space limitation of flow table and switch capacity, various issues exist in dealing with the flows. The existing schemes typically employ reactive approach such that the selection of evicted entries occurs when timeout or table miss occurs. In this paper a proactive approach is proposed based on the prediction of the probability of matching of the entries. Here eviction occurs proactively when the utilization of flow table exceeds a threshold, and the flow entry of the lowest matching probability is evicted. The matching probability is estimated using hidden Markov model (HMM). Computersimulation reveals that it significantly enhances the prediction accuracy and decreases the number of table misses compared to the standard Hard timeout scheme and Flow master scheme.