  Interactive, real-time, and high-quality cloud video games pose a serious
challenge to the Internet due to simultaneous high-throughput and low round
trip delay requirements. In this paper, we investigate the traffic
characteristics of Stadia, the cloud-gaming solution from Google, which is
likely to become one of the dominant players in the gaming sector. To do that,
we design several experiments, and perform an extensive traffic measurement
campaign to obtain all required data. Our first goal is to gather a deep
understanding of Stadia traffic characteristics by identifying the different
protocols involved for both signalling and video/audio contents, the traffic
generation patterns, and the packet size and inter-packet time probability
distributions. Then, our second goal is to understand how different Stadia
games and configurations, such as the video codec and the video resolution
selected, impact on the characteristics of the generated traffic. We also
evaluate the ability of Stadia to adapt to different link capacity conditions,
including cases where the capacity drops suddenly, as well as sudden increases
in the network latency. Our results and findings, besides illustrating the
characteristics of Stadia traffic, are also valuable for planning and
dimensioning future networks, as well as for designing new resource management
strategies. Finally, we compare Stadia traffic to other video streaming
applications, showcasing the main differences between them, and introduce a
traffic model using our captures. We show that this model can be used in
simulations to further investigate the network performance in presence of
Stadia traffic.
