  Due to the COVID-19 pandemic, many governments imposed lock downs that forced
hundreds of millions of citizens to stay at home. The implementation of
confinement measures increased Internet traffic demands of residential users,
in particular, for remote working, entertainment, commerce, and education,
which, as a result, caused traffic shifts in the Internet core. In this paper,
using data from a diverse set of vantage points (one ISP, three IXPs, and one
metropolitan educational network), we examine the effect of these lockdowns on
traffic shifts. We find that the traffic volume increased by 15-20% almost
within a week--while overall still modest, this constitutes a large increase
within this short time period. However, despite this surge, we observe that the
Internet infrastructure is able to handle the new volume, as most traffic
shifts occur outside of traditional peak hours. When looking directly at the
traffic sources, it turns out that, while hypergiants still contribute a
significant fraction of traffic, we see (1) a higher increase in traffic of
non-hypergiants, and (2) traffic increases in applications that people use when
at home, such as Web conferencing, VPN, and gaming. While many networks see
increased traffic demands, in particular, those providing services to
residential users, academic networks experience major overall decreases. Yet,
in these networks, we can observe substantial increases when considering
applications associated to remote working and lecturing.
