COC - hierarchical coflow ordering for WAN bandwidth optimization in inter-data center.

In recent years, more and more applications involving large-scale data analytics tend to be geo-distributed [6]. Those applications distribute intermediate data into different data centers, and generate traffic going through WAN links between data centers, which are expensive resources for service providers. Many global service providers like Microsoft, Google, and Facebook have already developed their SD-WAN traffic engineering systems [5, 7, 8] to optimize the bandwidth allocation across their inter-data centers.