Caracteriza\c{c}\~ao de tempos de ida-e-volta na Internet

TL;DR

This study measures and analyzes round-trip times (RTTs) across a large network of PlanetLab nodes, revealing distribution patterns, variability, and link quality groupings crucial for Internet application performance.

Contribution

It provides a comprehensive dataset of RTT measurements and identifies Gamma distribution as the best fit, along with classifying links into five quality-based groups.

Findings

Over 550 million RTT measurements collected

Gamma distribution best models RTT data

Links categorized into five distinct quality groups

Abstract

Round-trip times (RTTs) are an important metric for the operation of many applications in the Internet. For instance, they are taken into account when choosing servers or peers in streaming systems, and they impact the operation of fault detectors and congestion control algorithms. Therefore, detailed knowledge about RTTs is important for application and protocol developers. In this work we present results on measuring RTTs between 81 PlanetLab nodes every ten seconds, for ten days. The resulting dataset has over 550 million measurements. Our analysis gives us a profile of delays in the network and identifies a Gamma distribution as the model that best fits our data. The average times observed are below 500 ms in more than 99% of the pairs, but there is significant variation, not only when we compare different pairs of hosts during the experiment, but also considering any given pair of hosts over time. By using a clustering technique, we observe that links can be divided in five distinct groups based on the distribution of RTTs over time and the losses observed, ranging from groups of near, well-connected pairs, to groups of distant hosts, with lower quality links between them.