The document discusses the components and requirements of interactive television (ITV). ITV allows subscribers to access and interact with video programs on demand. Key components of an ITV system include set-top boxes at subscribers' homes, a broadband access network, video servers hosting content, and a service gateway. An effective ITV system demands high transmission speeds, quality of service guarantees, and point-to-point connections to enable on-demand video delivery and true video on demand services.

1. PrePared by:
Kind KiSHOR
Tribhuvan university
ITV

2.  ITV (interactive television) allows subscribers to access video
programs when they want and to interact with them.
 Requires a very high transmission rate and stringent QoS
guarantees.
 Demands point-to-point switched connections, good customer
services and excellent management for information sharing, billing
and security.
KIND@KISHOR
2
Introduction

3. 1. A home terminal commonly known as the Set-Top Box (STB) or
Customer Premises Equipment (CPE).
2. An access network.
3. A network-based server.
4. A powerful user-friendly interface.
KIND@KISHOR
3
Components of ITV

4.  STB (or CPE) typically takes the form of a box sitting on the top
of the TV set.
 STB connects to both the television and an external
communication network using a subscriber drop or loop.
 When interactive services are offered, the complexity and cost of
the STB increases.
 A service may require that more than one server be implemented,
or a server may implement more than one service.
KIND@KISHOR
4
Contd….

5.  ITV servers are a collection of computing, storage and
communications equipment interactive video services.
 Two key components of the server technology are;
 Logical organization of the multimedia samples in a file system or
database
 Techniques by which media components can be continuously
recorded or played back from the server.
 The multimedia database server must ensure that the recording and
presentation follow a real-time data rate.
KIND@KISHOR
5
Contd….

6.  VoD is an important ITV service.
 It provides electronic video-rental services across the broad band
network.
 Customers are allowed to select programs from remote massive
video archives, view them at the time they want without leaving the
comfort of their homes and interact with the programs.
 A VoD system that satisfies requirements is called a true VoD
system and is said to provide true VoD services.
 Otherwise it is called a near VoD system.
KIND@KISHOR
6
VoD (Video on Demand)

7.  One way to allow true VoD services is to have a dedicated video-
stream for each customer.
 This is expensive and wasteful of the system resources because the
system has to deliver multiple identical copies to the multiple users
at the same time.
 To reduce this cost, batching may be used.
 A protocol called Split-and-Merge (SAM) has been proposed to
provide true VoD.
KIND@KISHOR
7
True VoD

8. KIND@KISHOR
8
VoD system components include video server, broadband
network, set-top boxes, and service gateway.

9.  It consists of massive storage and media controllers.
 It stores a large number of digitized videos and serves a
considerable number of simultaneous video requests to the same
or to different videos on demand.
 It may be located at the local or regional switch of the network
provider or at remote information archives.
 Its basic functions include request handling, random access, and
user interactions.
KIND@KISHOR
9
Video Server

10.  It delivers video programs from the video server to the customers.
 It must have a very high data rate and must satisfy the real-time
delivery constraints of video traffic.
 It consists of two major components:
 the backbone network with high-speed switches, and
 the local access network.
 The backbone network links the remote video server at
geographically dispersed locations and the regional, national or
international information archives.
KIND@KISHOR
Broadband Network
10

11.  It serves as the bridge between the subscribers and the system.
 The major functions are receiving the incoming videostreams,
demodulating, demultiplexing and decoding the signals,
performing the necessary signal conversion, and sending outgoing
control messages.
 It must accommodate the heterogeneity of technologies and
formats from various controls to services.
 Its usefulness is in its adaptation to the diversity of access
networks, service providers, applications and user interfaces.
KIND@KISHOR
11
Set-top-boxes (STB)

12.  It may be integrated with an access node or may be a separate element in
the network.
 Its main functions are:
 Directory services to provide menu browsing and program scheduling.
 Mapping from service identity to corresponding location and program
provider.
 Controlling, coordinating, and signaling for multimedia session
establishment, maintenance, and disconnection.
 System management.
 Subscriber profile maintenance and billing.
 Secure communication to prevent unauthorized access.
KIND@KISHOR
12
Service Gateway

13.  Video server placement.
 Servers need to be changed periodically.
 Requires more communication and storage costs.
 Complexity in managing servers.
KIND@KISHOR
13
Issues of VoD

14. The End
KIND@KISHOR
14
THANK YOU
The house is open for queries.