And in the old days, okay, TV was delivered by broadcast over the air, by
satellites, or through cables. So why is this switching now to IP
technology? And this is a, a powerful example of the
phenomena of IP convergence that happened in the early part of the the century.
One reason is cost reduction, okay as you consolidate uniform platform based on IP,
then it can reduce cost. Another is flexibility, as we have seen
IP's greatest strength is that it's ability to support diverse applications
and the needs arriving in the future. And the third is that the compression
technology has gotten better and better over the last twenty years, for video,
such that at this point access network capacity can tolerate video, TV
distribution. So that is the switch from the
traditional satellite or over the air into, IP-based TV.
And this is a, typical picture, showing the, main component.
This is a home, another home, another home.
This one might be using a cable, modem, okay,
through a, customer premise, equipment CPE.
And that's connected into a set-top box on, your TV, and then, a WiFi gateway
for, the rest of your data traffic, in, your home.
And this one's connected through a passive optical network, okay.
So the physical medium is not a cable line but a fiber optic line.
And this goes into, an optical network unit which again is connected to, TV and
to WiFi gateway. And this one, goes through DSL, which is
a copper-based broadband access, into, a DSL modem, which in turn goes to set-top
box and WiFi gateway. Now next lecture we'll talk a lot about
these WiFi, including in-home and public area WiFi access points.
Then. This is the access network part okay, it
may cover in each distribution area somewhere between you know, around 32 to
128 kind of houses. And this, then, goes into, metro and then
backbone network. Skipping quite a few hops, we reach, a
media serving head end, and this head end may be connected to a local antenna that
can receive signals from local TV stations.
And these are then connected into a super head end.
usually there are just a few in a country like US, which has a big satellite dish
that can get the, content signal distributed via satellites.
And you, as you can see that, there are lot of equipments, both on access part
and also on the, backbone content on the very prior to this, deployed by a company
such as cable or phone company. In contrast, another way of using the
Internet for video, is VOI, Video over the Internet.
In this case all you need is a big data pipe, leading into, the user.
And then they can view application overlays to deliver the video you want.
So this is delivered over a public network, okay.
Or, in, perhaps some strict sense of the word, over, the Internet, okay.
It is not delivered, over, a managed private network.
And there are few variances, variations, one is a client server based
architecture. For example, YouTube or say ABC, BBC and
so on. Okay.
And they don't charge you a fee, they have other business model to support
their operation. Another par, possibility is CLI server
base architecture. But they will charge you a fee.
For example, Amazon Prime or Hulu Plus, or HBO Go, or Netflix.
So they will may charge you a monthly or annual fee.
And the third type is a P2P. And often they are free.
For example, Bit Torrent or PPLives. So there are different business revenue
model for them, and they have to also pay.
Even though they don't have to build their own network, they do have to pay
for the content they are delivering. Okay? Often, these companies have to
strike some special deal with the owner of the content.
They have to still buy servers. We'll see both content servers and
control servers. They may have to lease or buy network
capacity. They may also roll out some customer
premise equipments, although they may also just leverage existing mobile
devices, like your phone or tablet. And then, of course, they have to pay for
the software that monitors the services and configures the video delivery.