348 ◾ IP Communications and Services for NGN
Core Network Requirements
From Figure 19.3, the input to the core network is a series of compressed video as
IP packets. is is wherefrom IPTV derives its name. e TV frames are prepared
as IP packets and transmitted through the core IP network. Where an IP core net-
work is not available, a media gateway is used to re-cast the IP packets into the form
that the core network is able to carry (for example, into ATM cells and carried by
an ATM-based network). At the receiving end, they are re-cast back into IP packets
and reconstructed for viewing.
e high-speed core Internetwork functions as a multicast network so it is able
to serve many customers simultaneously, providing picture quality with gua ...