Load balanced spanning tree routing for Ethernet Networks

Ethernet's move into metropolitan and wide area networks is driving a rapidly growing market opportunity. Current Ethernet services come in two basic flavours, namely, Ethernet line and LAN providing point-to-point and multipoint connectivity respectively. The LAN services though more cost-effective in nature are lagging behind in deployments due to associated QoS and bandwidth provisioning issues. The Ethernet service provider needs to provision the network to meet current and future traffic demands where traffic is unpredictable and bursty with the goal to minimize over-provisioning and complexity. To add to the challenge, Ethernet forwarding is based on simple self-learning and relies on spanning tree routing. In this paper we propose an Ethernet specific load balanced routing mechanism, which is robust to dynamic traffic demands, requires minimal over-provisioning, is simple, static and requires only bandwidth profile associated with SLAs at the ingress and egress links. Our simulation results show that our scheme provides performance improvements as compared to the traditional approach in Ethernet as well as the related load balancing approach for optical/IP networks.