s) have entered the TV delivery business by using the convergence of all services onto IP networks (which telecom operators have and operate), while in the twentieth century broadcast TV was typically delivered via separate networks (rather than telecom operator's telephone networks) and hence it was a separate business. There are three main types of IPTV functional architecture: Non-NGN IPTV architecture. In this approach IPTV services are provided by using proprietary platforms in combination with standardized IP networking technologies and Internet application level technologies (e.g. HTTP can be used for presentation purposes). In this approach the IPTV streams are created in the operator's network, and also set-top boxes (on the end-user's side) are proprietary, developed and pro- vided to end-users by the telecom operator (which is the IPTV service provider). From the four IPTV domains, only the content provider is outside the telecom opera- tor's network. QoS is provided by bandwidth reservation per IPTV channel combined 6 Services in Fixed and Mobile Ultra-Broadband with traffic shaping in the network and playout buffering on the end-user's side (at the IPTV set-top boxes). This is the approach most used by telecom operators in the late 2000s and in the 2010s, and it will not change drastically in a short period of time. NGN-based IPTV functional architecture. In this case IPTV services are provided with NGN functional entities. For QoS support, NGN-based IPTV uses RACF for resource reservation and admission control functions. There are two possible sub-architectures: IPTV over non-IMS NGN. It provides IPTV service without deployment or usage of an IMS. IPTV over IMS-based NGN. It uses IMS functional entities for IPTV service pro- visioning. In the longer term the IMS-based NGN should be a typical approach for IPTV provisioning by using also inter-operator transfer of IPTV streams (which will be possible due to the standardized nature of the IMS-based NGN architecture, similar to its use for operator's Vo