Detection of Multipath Routing with Passive Delay Measurements

Multipath routing that enables more than a single active routing path between two end hosts is a common technique to improve the efficiency of load balancing. However, network performance metrics like the link delay and loss on different paths may vary a lot, leading different QoSes among end users. In this paper, we propose to utilize passive delay measurements between end-hosts, and employ both t-Test and the variance test to detect whether there is multipath routing. This is motivated by the investigation that the obtained distributions of passive delays between end - to-end communication flows can be very similar to each other when they are routed by the identical end-to-end path. Simulations based on NS2 validate the efficiency of both the t-Test and the variance test based approaches. Since the t-Test approach explores the features of averaged delays, it demonstrates great robustness against time asynchronousness of the delay measurements between different flows.