 dial-up modem and the latter consisted of voice traffic. With respect to either, the local telephone company simply served as a passthrough. The key function served by ISPs was to convert the analog signal into a digital signal and to provide the connection between the modem banks dispersed in communities The Regulation of Last-Mile Broadband Networks throughout the country and the limited number of network access points served by the backbones. ISPs perform a number of other functions, including supplying e-mail servers, hosting end users' Web pages, offering proprietary content, and caching the popular content locally SO that customers can access it more easily. The arrival of broadband technologies has effected some fundamental changes in the Internet's architecture. Because both DSL and cable modem providers use the same infrastructure to provide two different types of service (either cable television combined with cable modem service or local telephone service combined with DSL), both types of providers must maintain equipment to segregate the two different communication streams. As discussed earlier, DSL systems route traffic through devices known as a digital subscriber line access multiplexers (DSLAMs), which separate the voice communications from the data-based communications. Cable operators employ devices known as frequency up-converters and cable modem termination systems (CMTSs) to divide the video and data streams. Unlike what was the case in the narrowband world, last-mile broadband providers must maintain packet-switched networks in their main facilities to hold and route the streams of data packets after they have been separated from other types of communications. Once broadband networks were required to maintain their own data networks, it was a relatively simple matter for them to cut out the ISP and simply to negotiate their own interconnection agreement with a backbone provider. Indeed, given that last-mile providers already had to perform most of the functions previously provided by ISPs, i