tures in cost-reducing transmission technologies. Regardless of whether interconnection access increases or decreases demand, any unanticipated deviations in the level of network traffic can increase costs and affect network performance. Interconnection access prevents network owners from obtaining the information needed to make these decisions through direct observa- tion. Instead, it must obtain that information from its competitors, which may be under no legal obligation or economic incentive to provide it. Interconnection access also affects network design in other ways. Unlike retail and wholesale access, which only introduce traffic at locations where the network already serves customers, interconnection access requires networks to provide ser- vice at new locations within the network where the network was not previously offering service, although those interfaces are likely to be at major nodes. Intercon- nection access thus requires network owners to develop new systems to provision and meter usage at new points within their networks. It also introduces new flows in the middle of the network, which can be more difficult to manage than flows introduced at traditional customer locations. The architecture of the Internet is such that last-mile providers generally do not interconnect with one another directly. Instead, DSL and cable modem providers serving the same area typically interconnect indirectly through the Inter- net backbone. This greatly minimizes many of the problems traditionally associated with interconnection access. Scholars concerned about promoting interconnection access have nonetheless raised the concern that backbone providers might strategi- cally engage in discriminatory interconnection or refuse to interconnect altogether in ways that are privately beneficial, but economically harmful (Varian 1998; Speta 2002; Economides 2005; Werbach 2007). As a recent working paper issued by the FCC Office of Plans and Policy notes, a wide variety of legitimate reasons exist for refusing to interconn