IPTV Architecture

Telephone companies will most likely be the first ones to offer IPTV service. Later on, this facility will be extended to other current television carriers. IPTV is not a costly affair, and it is even both operator and consumer friendly. Because it uses the Internet and sends less information compared to standard analog or digital television, IPTV promises both lower costs for operators and lower prices for consumers. The use of set-top boxes through broadband or DSL Internet is very helpful to transfer video signals. Therefore, video can be streamed to households more efficiently compared to signaling by coaxial cable. In addition to its higher speed, it can record multiple programs at once by use of digital video recorders (DVR). In ROI terms, the copper was already paid for by the phone service and the fibre/DSL by the broadband service. Therefore, IPTV only has incremental costs.
Let us have a look at the architecture of IPTV through Figure :

The IPTV architecture consists of the following functional components:

Content Sources: The 'Content Source' is defined as a functionality which receives video content from producers and other sources. Afterwards, these contents are encoded and store in an acquisition database for video-on-demand (VoD)
Service Nodes: The 'Service Node' is defined as a functionality which receives video streams in different formats. These video streams in different formats then
reformat and encapsulate it for transmission with appropriate quality of service (QoS) indications to the wide-area network. This makes it ready for delivery to customers. In regards to service management, the Service Nodes communicate with the customer premises equipment (CPE); for the subscriber, session and digital rights management, service nodes communicate with the IPTV service.

Wide Area Distribution Networks: The Wide Area Distribution Network is made up of distribution capability, capacity, and quality of service. It also consists of other capabilities, such as multicast, which is necessary for the reliable and timely distribution of IPTV data streams from the service nodes to the customer premises. Moreover, the core and access network cover the optical distribution backbone network and the various digital subscriber line access multiplexers (DSLAMs). This is located at the central office or remote distribution points.

Customer Access Links: In the customer access links, high-speed DSL technologies such as ADSL2+ and VDSL are required; with the help of such technology, customer delivery can be provided over the existing loop plant and through phone lines to homes. There are some other options available. Service providers may use a combination of fiber-to-the curb (FTTC) and DSL technologies for delivery to customers. They can also implement direct fiber-to-the-home (FTTH) access. However, good results depend on the richness of their IPTV service offerings.

Customer Premises Equipment (CPE): In context of IPTV, the CPE device is located at the customer premises. This provides the broadband network termination (B-NT) functionality. At a minimum, it may also include other integrated functions which can be routing gateway, set-top box, or home networking capabilities.

IPTV Client: The IPTV client is a functional unit which terminates the IPTV traffic at the customer premises. This is only a device, such as a set-top box, which performs the functional processing. The functional processing includes setting up the connection and QoS with the service node, decoding the video streams, channel change functionality, user display control and connections to user appliances such as a standard definition television (SDTV) or a high definition television (HDTV) monitor.