A low-latency multipath routing without elephant flow detection for data centers

Abstract

Multipath routing in data center has been studied intensively in recent years in order to minimize the finish time of data transfer or the latency of message sending. Existing scheme of splitting traffic at the granularity of packets can cause reordered packets within a TCP flow. Another alternative scheme of splitting traffic at the granularity of a flow avoids packet reordering but may increase latency as it does not differentiate between elephant and mice flows. A newer efficient approach is to split elephants down into many mice flows, and distribute them uniformly at random over all paths. However, elephant detection is mandatory and the performance is largely depends on accuracy of the elephant detection. We propose, a simple yet effective multipath routing that leverage the same idea of splitting elephants down into many mice flows but without any farther requirement of elephant flow detection by using the hard time-out based flow removal feature of OpenFlow switches. Furthermore, we integrate a VLAN based routing scheme to addresses the challenges of cost-effective scalability. As per our simulation using mininet, we found a 44% reduction in overall flow completion time (FCT) compared to TinyFlow and 32% reduction in the consumption of flow table entry resources inside of aggregate switches in datacenter.