  Since the outbreak of the COVID-19 pandemic, videoconferencing has become the
default mode of communication in our daily lives at homes, workplaces and
schools, and it is likely to remain an important part of our lives in the
post-pandemic world. Despite its significance, there has not been any
systematic study characterizing the user-perceived performance of existing
videoconferencing systems other than anecdotal reports. In this paper, we
present a detailed measurement study that compares three major
videoconferencing systems: Zoom, Webex and Google Meet. Our study is based on
48 hours' worth of more than 700 videoconferencing sessions, which were created
with a mix of emulated videoconferencing clients deployed in the cloud, as well
as real mobile devices running from a residential network. We find that the
existing videoconferencing systems vary in terms of geographic scope, which in
turns determines streaming lag experienced by users. We also observe that
streaming rate can change under different conditions (e.g., number of users in
a session, mobile device status, etc), which affects user-perceived streaming
quality. Beyond these findings, our measurement methodology can enable
reproducible benchmark analysis for any types of comparative or longitudinal
study on available videoconferencing systems.
