IPTV Protocol

As already discussed, IPTV covers both Live TV, i.e., multicasting, as well as stored video or VoD. The requirements for playback of IPTV are either a personal computer or a "set-top box" connected to a TV. Typically, the video content is a moving pictures expert group (MPEG) 2-transport stream (TS) delivered via IP multicast. This is a method in which information can be sent to multiple computers at the same time, with the newly released H.264 format predesigned to replace the older MPEG-2. In standard-based IPTV systems, the primary underlying protocols used for IPTV are Internet group management protocol (IGMP) and real time streaming protocol (RTSP). Here, IGMP is the version 2 for channel change signaling for Live TV and RTSP for VoD.

Currently, only one alternative exists to IPTV which is the traditional TV distribution technology covering terestial, satellite and cable TV. However, when there is a possibility for the cable TV, it can be upgraded to two-way capability system and thus also carry IPTV. Another alternative available is VoD which is usually delivered in the US over cable TV through the digital video broadcasting (DVB) protocol, but it is not labelled as IPTV services.

IPTV Home Distribution Scenarios

Generic IPTV Distribution Model for Customer Premises, showing arious interfaces per ITU Full Service VDSL Model


The following illustrates possible home network connectivity scenarios use IPTV service:

No IPTV Traffic on Home Network .The set-top box functionality and the ssociated IPTV Client, is integrated, or co-located, into the same box as the xDSL Termination rocessing unit (xDSL modem). Physical interfaces on this unit are the DSL phone line, Ethernet port, For Internet service, and the connections to standard TV and other home entertainment appliances. In this scenario, IPTV traffic does not traverse the home network.

Integrated xDSL Termination Processing (xDSL modem) and Set Top Box (IPTV Client)

IPTV-enabled Home Network .The xDSL modem and the set top box functionality are not integrated as one box. In such cases, the IPTV video streams are delivered from the xDSL modem to the set-top box, or TV monitor with an embedded IPTV client, over the home network.

Home Network Using Distributed Set-top Boxes and/or IPTV Client-enables Appliances

Pictoral of the Powerline Network Used for IPTV Distribution – Ethernet-enabled set-top boxes and Ethernet/PLC bridges make this possible.

Digital Media Server Added – it shows digital media server functionality, an emerging class of home entertainment devices with built-in storage, similar to; TiVo™, Personal Video Recorders (PVRs) and PCs with large storage for multimedia content. The media server functionality may be standalone or integrated into a set-top box. Content streams generated by the media server may share the home network, which must be able to differentiate and deliver the IPTV traffic in a manner that is consistent with the required QoS.

Distribution at Customer Premises showing a local Digital Media Server sharing the Home Network


Hybrid PLC/Cable/Ethernet Set-Top Box Concept

The fig shows a set-top box concept that includes PLC, coax and Ethernet network interfaces. The embedded PLC/Coax/Ethernet client makes this set-top box a plug-and-play network device, delivering audio and various video formats to the display and sound equipment.