Efficient building method of multiple spanning tree for QoS and load balancing

Recent traffic feature is far removed from the traffic trends seen during the early days of Ethernet technology. Therefore the current IEEE 802.1 standards and its extensions to the Spanning Tree protocol fall short of providing satisfactory quality of service for traffic which has a significant amount of QoS-sensitive traffic as well as stabilizing the traffic load among whole bridge network where root switch has to handle all traffic from its child switches. In the current and near-future scenario of switch networks with significantly large layer-2 clusters and numerous VLANs, we show significant shortcomings of the basic Spanning Tree and the Multiple Spanning Tree protocols with regard to QoS and load balancing. In this paper we propose a bridge ID scheme of Regional Root Identifier which is used in Multiple Spanning Tree Instance(MSTI) to provide the efficient building method of MSTI for QoS and load balancing. Through this scheme, the traffic source of P2MP application can set itself as the root of MSTI satisfying the QoS constraint while roots of several regular MSTIs are built in distributed way. We discuss the problem in building MSTI for P2MP application and regular MSTIs and present in detail our proposed scheme. Our experiments for two purposes show good improvement of QoS in terms of delay and load balancing of whole bridge network.