adical changes the Internet would bring to the communications world." 2 The FCC's definition of high-speed lines was initially developed in 1999 and has become some- what out of date. The FCC is in the process of updating its definitions (FCC 2008a). The Regulation of Last-Mile Broadband Networks provided to any one end user dependent on the number of other users. DSL service, although providing more limited bandwidth than cable modem service, employs dedicated connections that allow greater reliability. Despite these differences, end users typically regard the two services as relatively good substitutes for one another (Crandall et al. 2002; FCC 2005d3). Mobile wireless has emerged as an impor- tant competitor, skyrocketing from no subscribers at the beginning of 2005 to over 35 million subscribers by the end of 2006. In addition, Verizon is investing $24 billion in its new fiber-based FiOS network, which delivers unprecedented speeds. FiOS had already captured over one million subscribers by mid 2007 and hopes to reach seven million customers by 2010 (Verizon Communications, Inc. 2007). Despite the functional similarities between cable modem and DSL service, gov- ernmental authorities have taken strikingly different approaches when regulating them. Whereas cable modem services have been largely deregulated, DSL services have often been subject to extensive access requirements. 1. Regulation of Cable Modem Systems Cable modem systems provide service through the network of coaxial cables orig- inally designed for cable television, although some modifications to the network configuration are required. For example, the cable network must be transformed from the typical tree-and-branch configuration associated with one-way television transmission into the ring or star-type configuration needed for data transmission. This is usually accomplished through a hybrid fiber-coaxial (HFC) architecture in which fiber optic cables are used to connect the central cable facility (known as the "headend") to satellite facilities 