Abstract

Video conferencing applications (VCAs) have become a critical Internet application during the COVID-19 pandemic, as users worldwide now rely on them for work, school, and telehealth. It is thus increasingly important to understand the resource requirements of different VCAs and how they perform under different network conditions, including: how do application-layer performance metrics (e.g., resolution or frames per second) vary under different link capacity; how VCAs perform under temporary reductions in available capacity; how they compete with themselves, with each other, and with other applications; and how usage modality (e.g., gallery vs. speaker mode) affects utilization. We study three modern VCAs: Zoom, Google Meet, and Microsoft Teams. Answers to these questions differ substantially depending on VCA. First, the average utilization on an unconstrained link varies between 0.8 Mbps and 1.9 Mbps. Given temporary reduction of capacity, some VCAs can take as long as 50 seconds to recover to steady state. Differences in proprietary congestion control algorithms also result in unfair bandwidth allocations: in constrained bandwidth settings, one Zoom video conference can consume more than 75% of the available bandwidth when competing with another VCA (e.g., Meet, Teams). For some VCAs, client utilization can decrease as the number of participants increases, due to the reduced video resolution of each participant’s video stream given a larger number of participants. Finally, one participant’s viewing mode (e.g., pinning a speaker) can affect the upstream utilization of other participants.

Related Insights

Working Paper

A Comparative Analysis of Ookla Speedtest and Measurement Labs Network Diagnostic Test (NDT7)

A comparative analysis of two popular speed test tools: Ookla's Speedtest and Measurement Lab's Network Diagnostic Test.
May 24, 2022
Working Paper

What Can We Learn from Selected, Unmatched Data: Measuring Internet Inequity in Chicago

By integrating a “big” dataset of Speedtest Intelligence from Ookla that measures Internet performance and income data from the American...
May 05, 2022
Publication

A Tale of Three Datasets: Characterizing Mobile Broadband Access in the U.S.

We compare LTE coverage data from the FCC with a crowdsourced dataset from Skyhook for New Mexico.
Mar 01, 2022