  Inter-datacenter networks connect dozens of geographically dispersed
datacenters and carry traffic flows with highly variable sizes and different
classes. Adaptive flow routing can improve efficiency and performance by
assigning paths to new flows according to network status and flow properties. A
popular approach widely used for traffic engineering is based on current
bandwidth utilization of links. We propose an alternative that reduces
bandwidth usage by up to at least 50% and flow completion times by up to at
least 40% across various scheduling policies and flow size distributions.
