Performance of Capability Aware Spanning Tree Algorithm for Bridged Networks

In this paper, we suggest a new capability aware spanning tree(CAST) algorithm for Ethernet bridged network which consists of both legacy Ethernet bridges and synchronous Ethernet ones. The legacy spanning tree algorithm specified in IEEE 802.1D standard select root bridge and construct tree based on each bridge's identifier without consideration of each bridge's capability. Thus we note that if the legacy STP may assign a synchronous bridge as a root bridge, the bridge may become a bottleneck for asynchronous trafficbecause of bandwidth limitation for asynchronous traffic. In this paper, the CAST algorithm constructsmultiple spanning tree by using of bridge capability and makes different transmission path for each traffics, can removes this kind of defect. From the simulation results, we can see that the proposed CAST algorithm has better end-to-end delay performance than legacy spanning tree algorithm in high traffic load and multiple hops environment.