ENDIST: Edge node divided spanning tree

Abstract

Carrier Ethernet integrates distributed layer-2 bridged networks to a backbone network. Currently, Carrier Ethernet uses Multiple Spanning Tree Protocol (MSTP) that allows multiple spanning trees. Shortest Path Bridging (SPB) based on MSTP is expected to be a major routing scheme in coming era because SPB is simple and shows better performance. These layer-2 routing protocols are built on spanning trees and have a unique routing path between two end-nodes. If we alleviate the 'unique path limitation,' we are able to achieve a better routing protocol. Based on this philosophy, we propose Edge Node Divided Spanning Tree (ENDIST). In regular backbone networks, an edge node is generally connected to core networks with multiple separate links. Utilizing this property, ENDIST divides as many edge nodes as their connected links and generates trees based on SPB. Depending nodal status, ENDIST chooses a better routing path for flow-basis. This added ability contributes to level up the capacity of the layer-2 routing scheme. Through the simulation of the comparison between SPB, STP, and ENDIST, we verify the superior performance of ENDIST.