Spectral Characteristics of Saturated Links

Abstract— Internet protocols frequently create periodic patterns in traffic. Examples included packets paced by bottleneck links, periodic exchange of information such as routing, transport-layer effects such as TCP self-clocking, and application-level effects. Although measurement of such periodicities could shed light on Internet traffic, current understanding of periodic behavior in general traffic is quite limited. This paper explores this area by studying the spectral behavior of these kinds of traffic. Our technique is completely passive and can be applied to aggregate traces gathered at various observation points on the network. Unlike techniques measuring packet inter-arrival time, our technique does not require per-flow separation. Our experiments show that the signature of a saturated link persists in the presence of background traffic or when we observe only a portion of the traffic through the saturated link. We investigate how such signatures evolve as the traffic traverses through the network and identify the major influential factors that affect the signatures. Developing a technique to detect saturated links is part of our future work.