IPTV technology is part of a new breed of services designed to facilitate access to video entertainment. It provides access to digital TV over the IP transport medium from a head-end device to the end user’s TV set-top box (STB). Most service providers use a dedicated transport network to support IPTV.
A typical IPTV network is comprised of the following functional blocks :
- - National headend: Where most of the IPTV channels enter the network from national broadcasters
- - Core network: Usually an IP/MPLS network transporting traffic to the access network
- - Access network: Distributes the IPTV streams to the DSLAMs
- - Regional headend: Where local content is added to the network
- - Customer premises: Where the IPTV stream is terminated and viewed
Broadcast information coming from an antenna or a satellite dish at the national headend is mainly distributed using MPEG-2 multiprogram transport stream (or MPTS) to the video service node. Note that other more efficient, less bandwidth-hungry compression algorithms such as H.264 (MPEG-4 Part 10) or the Society of Motion Picture and Television Engineers (SMPTE) 421M (also known as VC-1) are making their way to the marketplace to complement this first offering.
The distribution of the actual SDTV or HDTV channel content is performed using various devices on the access network. Among these devices, digital subscriber line access multiplexers (DSLAM) as well as other technologies like fiber-to-the-home (FTTH) can be used to interface with the user’s STB. For IPTV, each channel is distributed using a multicast IP address.
