at are available. Greater accessibility to complements has the effect of increasing demand for network services. In addition, the fact that providers of complementary services are guaranteed access to all network customers reduces the level of business risk that they confront, which increases the economic viability of complementary service providers. The broader range of complementary service providers should enhance the demand for network capacity still further. On the other hand, platform access has the inevitable effect of favoring some applications and disfavoring others. Take TCP/IP, for example. One of the most distinctive features about TCP/IP is that it routes packets on a first come, first Networks in Telecommunications served basis without regard to the origin of the packets or the application with which they are associated. Although this approach is well suited to traditional Internet applications, such as e-mail and Web browsing, in which delays of a quarter second are unproblematic, it is less well suited to applications that are less tolerant of variations in throughput rates, such as streaming media and Internet telephony (also known as "voice over Internet protocol" or "VoIP"). Moreover, the packet anonymity inherent in TCP/IP restricts the ability to add security features designed to foster e-commerce or to protect against viruses and the other hostile elements that are proliferating on the Internet. To the extent that platform access forecloses the emergence of new, beneficial applications, it causes the demand for network capacity to decrease. The net impact on network demand thus ultimately depends upon whether the value of standardization dominates the value of product variety, or vice versa. Indeed, if the value of network diversity is sufficiently large, deviating from plat- form access can change the fundamental structure of the industry. This is because differentiation represents a classic solution to the pressures toward concentration created by the presence of large fixed costs. Varying