Making Broadband Access Networks Transparent to Researchers, Developers, and Users

today. However, most ISPs are hesitant to reveal details about their network deployments,
and as a result the characteristics of broadband networks are often not known to users,
developers, and researchers. In this thesis, we make progress towards mitigating this lack
of transparency in broadband access networks in two ways.

First, using novel measurement tools we performed the first large-scale study of the
characteristics of broadband networks. We found that broadband networks have very
different characteristics than academic networks. We also developed Glasnost, a system
that enables users to test their Internet access links for traffic differentiation. Glasnost
has been used by more than 350,000 users worldwide and allowed us to study ISPs' traffic
management practices. We found that ISPs increasingly throttle or even block traffic from
popular applications such as BitTorrent.

Second, we developed two new approaches to enable realistic evaluation of networked
systems in broadband networks. We developed Monarch, a tool that enables researchers to
study and compare the performance of new and existing transport protocols at large scale
in broadband environments. Furthermore, we designed SatelliteLab, a novel testbed that
can easily add arbitrary end nodes, including broadband nodes and even smartphones, to
existing testbeds like PlanetLab.