  Internet eXchange Points (IXPs) are Internet hubs that mainly provide the
switching infrastructure to interconnect networks and exchange traffic. While
the initial goal of IXPs was to bring together networks residing in the same
city or country, and thus keep local traffic local, this model is gradually
shifting. Many networks connect to IXPs without having physical presence at
their switching infrastructure. This practice, called Remote Peering, is
changing the Internet topology and economy, and has become the subject of a
contentious debate within the network operators' community. However, despite
the increasing attention it attracts, the understanding of the characteristics
and impact of remote peering is limited. In this work, we introduce and
validate a heuristic methodology for discovering remote peers at IXPs. We (i)
identify critical remote peering inference challenges, (ii) infer remote peers
with high accuracy (>95%) and coverage (93%) per IXP, and (iii) characterize
different aspects of the remote peering ecosystem by applying our methodology
to 30 large IXPs. We observe that remote peering is a significantly common
practice in all the studied IXPs; for the largest IXPs, remote peers account
for 40% of their member base. We also show that today, IXP growth is mainly
driven by remote peering, which contributes two times more than local peering.
