Therefore, the role of Internet service providers (ISPs) that are responsible for quality of service (QoS) has expanded (Wu, 2003) to allow for others to use the network, and to control and manage the network to operate well. Moreover, a wide and stable network is the most important determinant of the quality of newly developed Internet application services that use wide bandwidth and are latency sensitive2. Therefore, the role and market power of ISPs are increasing, and ISPs are attempting to profit from their market power. With the expectation of forthcoming application services that will use a wider bandwidth and be more latency sensitive, the market power of ISPs will increase and the debate over network neutrality will continue.