Today's emerging traffic is far removed from the traffic trends seen during the early days of Ethernet technology. As a result, 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 multimedia and VoIP traffic. In the current and near-future scenario of campus-wide networks with significantly large layer-2 clusters and numerous virtual LANs (VLANs), we show significant shortcomings of the basic spanning tree and the multiple spanning tree protocols with regard to QoS. We propose a novel, simple, and yet highly effective enhancement to the multiple spanning tree protocol to achieve a high degree of QoS by keeping in perspective the different characteristics of the various traffic types in the Diffserv framework. We discuss the problems of the current standards and present in detail our proposed extension to overcome them. Our simulation results show good improvements in throughput and significant benefits in delay for all classes of traffic to conclusively prove our claims.
['Yujin Lim', 'Heeyeol Yu', 'Shirshanka Das', 'Scott Seongwook Lee', 'Mario Gerla']
QoS-aware multiple spanning tree mechanism over a bridged LAN environment