On the Consistent Migration of Splittable Flows: Latency-Awareness and Complexities

Network traffic demands change all the time, giving rise to the well-investigated topic of consistent network updates. We in this paper study the consistent migration of flows, in particular the avoidance of transient congestion. Most previous work implemented rather coarse-grained techniques, ignoring the effect of link latency in their computations. Recent work shows that, in order to achieve the goal of zero packet loss, earlier methods need to be adapted to cope with link latency. However, the current work only considers unsplittable flows, which are routed along a single path. We present the first study of splittable flows in this context, where a single flow may be spread over the network for better throughput and load balancing. Interestingly, splittable flows seem to be harder to tackle in this setting from a complexity point of view. Nonetheless, we provide the first methods and insights to integrate splittable flows into consistent update frameworks under the aspect of link latencies.