Layer-2 Routing Analytic Model by Linear Programming

Carrier Ethernet integrates distributed layer-2 bridge networks to a backbone network. Since carrier Ethernets use simple layer-2 routing, its performance is lower than that of layer-3 routing methods. We introduce an analytic model that evaluates the routing methods in backbone networks. The model solves the multi- input and multi-output maximum flow problem in backbone networks using linear programming. Our method can be used as follows. Firstly, the model suggests appropriate link capacity if network topology and traffic pattern is given. Secondly, the model shows and compares the performance of layer-2 routing methods including perfect routing and our proposed routing called ENDIST(Edge Node Divided Spanning Tree). In this study, the performance is the maximum throughput that a given routing method can reach. We additionally found many good results about ENDIST. Our analytic model proved that ENDIST outperforms the existing layer-2 standard protocols such as STP, MSTP for any offered load and performs perfectly under medium and light traffic load in the given network, thus enough to say that ENDIST is as good as layer 3 routing from the point of throughput.