Ring Flushing for Reduced Overload in Spanning Tree Protocol Controlled Ethernet Networks

Abstract

Abstract.Flooding causes serious problems to the scalability of Ethernet networks. Recent proposals to overcome this problem, such as SEATTLE [5], usually require significant changes in different network layers, making the realistic chance of their deployment questionable. In this paper, we propose Ring Flushing, a practical method to reduce the burden of flooding during topology changes. The basic idea behind our approach is to locate stale forwarding information in an efficient way. Ring Flushing abolishes the broadcast-like spreading of topology change information thus shrinking the flushing domain. We implemented Ring Flushing in OMNeT++ simulation environment and evaluated its performance in different topologies and parameter settings. Our simulations show that the Ring Flushing has clear advantage over the approach of standard Rapid Spanning Tree Protocol (RSTP) in terms of throughput during network recovery. Furthermore, the Ring Flushing diminishes overall network overload during topology changes as the network size increases.