tocol/Internet protocol (TCP/IP). The ubiquity and openness of TCP/IP allow a wide variety of applications to be transmitted over the Internet, permitting such services as search engines and Internet commerce to be provided by companies using the Internet. In addition, TCP/IP makes possible the transmission of a wide variety of types of information including voice, data, images, and video. Increases in the volume and heterogeneity of traffic have created some pressure on network owners to deviate from TCP/IP in favor of alternative protocols that can guaran- tee greater reliability in throughput rates. As discussed in more detail in the last three chapters of this book, critics have responded by calling upon policymakers to mandate adherence to TCP/IP. 5. Unbundled Access Mandated unbundled access requires network owners to lease portions of their networks to their competitors. Like wholesale access, unbundled access is provided to competitors. Rather than providing the services of the entire network, as is the case under wholesale access, unbundled access involves the use of the services of selected inputs. Unbundled access represents the culmination of a long-standing movement in network regulation. Regulatory authorities initially regarded the entire telephone network as a natural monopoly. As competition began to emerge in portions of the network, regulatory authorities adopted a policy of restricting rate regulation to the narrowest possible scope and deregulating the competitive portions of the network. This approach had the benefit of allowing the broadest possible scope of the industry to be governed by competition. Separating the regulated and unregu- lated lines of business also made it easier to enforce nondiscrimination mandates and to prevent regulated entities from including costs properly attributable to the competitive line of business in their regulated rates. This rationale is what led Judge Harold Greene to order AT&T to segregate its now-competitive long distance business from its local teleph