In order to fully utilize the bandwidth of multi-paths of the datacenter network (DCN)

existing studies mostly adopt the congestion-aware load-balancing scheme

which forwards traffic along the optimal path after dynamically obtaining global congestion information. However

these works do not consider the non-uniform distribution of flow size and are difficult to strike a balance between the routing cost and the forwarding efficiency. This paper proposes ULFC

a utilization-aware load-balancing mechanism based on flow classification. By analyzing the characteristics of traffic

ULFC classifies the flows based on their sizes and assigns paths to them using different strategies

realizing the best matching between the characteristics of traffic and the advantages of the routing method. We evaluate ULFC with simulation and the results show that it outperforms the existing schemes in average flow-completion time (1.3~1.6×)

while the routing cost has been reduced by more than 50%.