Characterizing end-host application performance across multiple networking environments

International audienceUsers today connect to the Internet everywhere - from home, work, airports, friend's homes, and more. This paper characterizes how the performance of networked applications varies across networking environments. Using data from a few dozen end-hosts, we compare the distributions of RTTs and download rates across pairs of environments. We illustrate that for most users the performance difference is statistically significant. We contrast the influence of the application mix and environmental factors on these performance differences

A Change-of-Measure Approach to Per- Flow Delay Measurement Combining Passive and Active Methods : Mathematical Formulation for CoMPACT Monitor

One problem with active measurement is that, while it is suitable for measuring time-average network performance, it is difficult to measure per-flow quality of service (QoS), which is defined as the average over packets in the flow. To achieve such per-flow QoS measurement, the authors proposed a new technique, called the change- of- measure-based passive/active monitoring (CoMPACT Monitor), which is based on the change-of-measure framework in probability/measure theory and transforms actively obtained information by using passively monitored data. This technique enables us to concurrently measure one-way delay information about individual users, applications, and organizations in detail in a lightweight manner. This paper presents the mathematical formulation for the CoMPACT Monitor and verifies that it works well under some weak conditions. In addition, we investigate its characteristics regarding several implementation issues through simulation and actual network experiments. The results reveal that our technique provides highly qualified estimates involving only a limited amount of extra traffic from active probes

Poisson versus periodic path probing (or, does pasta matter

See Time Averages”) property states that, under very general conditions, the fraction of Poisson arrivals that observe an underlying process in a particular state is equal, asymptotically, to the fraction of time the process spends in that state. When applied to network inference, PASTA implies that a Poisson probing stream provides an unbiased estimate of the desired time average. Our objective is to examine the practical significance of the PASTA property in the context of realistic RTT, loss rate and packet pair dispersion measurements with a finite (but not small) number of samples. In particular, we first evaluate the differences between the point estimates (median RTT, loss rate, and median dispersion) that result from Poisson and Periodic probing. Our evaluation is based on a rich set of measurements between 23 PlanetLab hosts. The experimental results show that in almost all measurement sessions the differences between the Poisson and Periodic point estimates are insignificant. In the case of RTT and dispersion measurements, we also used a non-parametric goodness-of-fit test, based on the Kullback-Leibler distance, to evaluate the similarity of the distributions that result from Poisson and Periodic probing. The results show that in more than 90% of the measurements there is no statistically significant difference between the two distributions.