Delay-Optimized Video Traffic Routing in Software-Defined Inter-Datacenter Networks

Many video streaming applications operate their geo-distributed services in the cloud, taking advantage of superior connectivities between datacenters to push content closer to users or to relay live video traffic between end users at a higher throughput. In the meantime, inter-datacenter networks also carry high volumes of other types of traffic, including service replication and data backups, e.g., for storage and email services. It is an important research topic to optimally engineer and schedule inter-datacenter traffic, taking into account the stringent latency requirements of video flows when transmitted along inter-datacenter links shared with other types of traffic. Since inter-datacenter networks are usually overprovisioned, unlike prior work that mainly aims to maximize link utilization, we propose a delay-optimized traffic routing scheme to explicitly differentiate path selection for different sessions according to their delay sensitivities, leading to a software-defined inter-datacenter networking overlay implemented at the application layer. We show that our solution can yield sparse path selection by only solving linear programs, and thus, in contrast to prior traffic engineering solutions, does not lead to overly fine-grained traffic splitting, further reducing packet resequencing overhead and the number of forwarding rules to be installed in each forwarding unit. Real-world experiments based on a deployment on six globally distributed Amazon EC2 datacenters have shown that our system can effectively prioritize and improve the delay performance of inter-datacenter video flows at a low cost.