Micro-Time-Scale Network Measurements and Harmonic Effects

As network transmission speeds increase, packet streams increasingly uncover fine details of the interior behavior of router hardware and software. This behavior reveals itself as a set of harmonic effects, as interior clocks periodically interrupt packet forwarding, and interior queues periodically empty and fill. We examine this behavior with a Linux-based router employing a variety of gigabit Ethernet interfaces, with a view toward two goals: the creation of harmonic models of router forwarding performance which are accurate and yet mathematically simple and fast; and the analysis of the potential for an undesirable succession of positively reinforcing router “reverberations.”