 admission control to ensure QoS. It manages network bandwidth to secure bandwidth used by prioritized traffic which was admitted by admission control, and restricts malicious overflow traffic. RACF controls the edge router to open and close the Real-Time Protocol (RTP) port to coordinate with call control, SO that it can restrict the calls in congestion and spoofing traffic which did not go through regular SIP negotiation. 4.2.1.2.2 NACF In NGN, there are two levels of authentication defined. They are access level authen- tication that allocates the IP address, and service application level authentication to use SIP. Out of these, NACF performs the network access level authentication Service Delivery Platforms based on user profile. It also has functions such as managing the IP addresses and connection information of currently connected terminals, and providing QoS pro- file information to RACF. An example of services provided by NGN based on such architectures is IPTV. In ITU-T, FG-IPTV has been discussing three types of architectures to provide IPTV, which are non-NGN, non-IMS-based NGN, and IMS-based NGN. In September 2008, the standardization of IPTV requirement condition Y.1910 was approved, which completed the basic specifications to provide IPTV by IMS-based NGN. Examples of the advantages of providing Internet Protocol based Television (IPTV) service using NGN as service control platform are QoS (bandwidth/ priority control) is guaranteed. User authentication, charging, and profile management functions can be used. Mobility, FMC are realized. Services can be provided to roaming users on different types of network. Also, by cooperating with other services, realization of "blended services" such as receiving voice call and displaying messages while watching IPTV, and seamless broadcast control in which broadcast is optimized for the functions of the terminals used to watch IPTV are being discussed. 4.2.2 NGN IMS Service Provisioning and Third-Party Service Access The objective for the NGN service creation 