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Lecture 1

Multimedia Communications

TCO 7021 Internetworking Multimedia

FACULTY OF INFORMATION TECHNOLOGY, MULTIMEDIA UNIVERSITY

Contact

Dr. Poo Kuan Hoong

[email protected]

FIT Building: Room BR4004

03-8312 5202

Consultation Hours:

Wednesday: 2:00 pm – 4:00 pm

Thursday: 2:00 pm – 4:00 pm

http://fit.mmu.edu.my/


Textbook and References

Textbooks

Fred Halsall, “Multimedia Communications”, Pearson,

2001.

S. Thomas, “ IPng and the TCP/IP Protocols:

Implementing the Next Generation Internet”, 1996.

D. Messerschmitt, “Understanding Networked

Applications: A First Course” , Morgan Kaufmann,

1999.

M. Rhee, “Internet Security”, Wiley, 2003.



Course Assessment

40% Final Examination

40% Assignment

20% Mid-Term Test

PLAGIARISM will not be tolerated and will be

handled with seriously in this course



Course Objectives

To expose the principles and issues underlying

internetworking multimedia technologies as they are

today and as they are likely to evolve in the future.


1-6 FACULTY OF INFORMATION TECHNOLOGY, MULTIMEDIA UNIVERSITY


Learning Objectives

To understand and learn about the networking evolution.

To understand the network types.

To discuss multimedia requirements in the communication systems.

To understand the basics of a multimedia communication system.

To illustrate multimedia networks.

To know the Internet protocol suite for multimedia communications.




Introduction

Multimedia communications embraces a range of applications and networking infrastructures.

The term “multimedia” is used to indicate that the information/data being transferred over the network may be composed of one/more media: Text

Images

Audio

Video

Communications may be in the form of person-person communications or person-to-system communications




Introduction




Introduction

There are a number of different types of network that are used to provide the networking infrastructure eg. Public switched telephone network (PSTN)

Multimedia information is represented in various formats

Text : characters are represented by fixed number of binary digits (bits) known as codeword

Digitized image : 2-dimensional block known as picture element (pixel)

Digitized Audio/video : converted analog signal measured in bits per second which is normally compressed




Multimedia Networks

There are 5 basic types of communication networks

Telephone networks

Data networks

Broadcast television networks

Integrated services digital networks

Broadband multiservice networks




Telephone Networks

PSTN have been in existence for many years and have gone through many changes during this time.

Initially was designed to provide basic switched telephone service.




Telephone Networks




Telephone Networks




Data Networks

Data networks were designed to provide basic data communication services such as electronic mail (email) and general file transfers.

Equipment connected to such networks are computer, PC, workstations, or email/file server.

2 most likely deployed networks are X.25 network and the Internet.

X.25 network is restricted to low bit rate data applications and hence is unsuitable for most multimedia applications.




Data Networks

The Internet is made up of a vast collection of interconnected networks which use the same set of communication protocols.

Communication protocol is an agreed set of rules that are adhered to by all communicating parties for the exchange of information.




Broadcast Television Networks

Broadcast TV networks were designed to support the diffusion of analog TV (and radio) programs throughout wide geographical areas.

Large town/city the broadcast medium is normally a cable distribution network

Larger areas use satellite network or terrestrial broadcast network




Integrated Services Digital

Networks (ISDN)

Deployed in the early 1980s to provide additional services to PSTN.

Convert the access circuits that connect user equipment to the network into all-digital form

Provide telephone call and data call services

With ISDN, the access circuit is known as digital subscriber line (DSL).

Digitization of a telephone quality analog speech signal produces constant bit rate binary system – bitstream of 64kbps





Networks (ISDN)

Broadband multiservice networks were designed to

support a wide range of multimedia communication

applications.

The term “broadband” was used to indicate that the

circuits associated with a call could have bit rates in

excess of the maximum bit rate 2Mbps (30 X 64

kbps) provided by an ISDN.





Networks (ISDN)

Data networks operate in packet mode.

A packet is a container for a block of data where

the head of the packet contains address of the

intended packet recipient.

For multimedia applications, binary stream is

divided into fixed sized packets known as cells.

Different multimedia applications generate

different cell streams of different rates thus

asynchronous transfer mode (ATM) networks




Multimedia Applications

There are many and varied applications that

involve multiple media types. In general, can be

places into 3 categories:

Interpersonal communications

Interactive applications over the Internet

Entertainment applications




Interpersonal Communications

May involve speech, image, text, or video.

Some cases just a single type of medium while

others two/more media types are integrated

together.

Speech – uses the traditional PSTN

Alternatively can use multimedia PC with software –

computer telephony integration (CTI)

Telephone over the internet is known as voice over

IP (VoIP)





Image - Alternative form of interpersonal

communications over a PSTN/ISDN is by using

facsimile or fax.

Scan and digitize image of a document and

transmit over the network.

Text – involving electronic mail (email)

Email server contains a mailbox for each user

connected to a network.





Speech and video – eg. Video telephony

Requires higher bandwidth due to the integration of

video and audio.

Some networks such as LANs and the Internet

support multicasting.

Multicasting – transmission from any

PCs/workstations belonging to a predefined

multicast group are received by all the other

members of the group.




Interactive applications over the

Internet

Most widely used with a World Wide Web

(WWW) or web.

The web consists of inter-linkage multimedia

information servers that are geographically

distributed around the Internet.




Entertainment Applications

Can be one of two parts :

Movie/video on-demand

Interactive TV




Application & Networking

Terminology




Communication Modes




Network Types

There are 2 types of information stream associated

with the different media types – continuous and

block-mode

There are 2 types of communication channels –

circuit mode (time-dependent) and packet mode

(time varying)

Circuit mode is also synchronous communication

channel since it provides a constant bit rate service

While packet mode is asynchronous communication

channel as it provides variable bit rate service




Circuit Mode




Packet Mode

There are 2 types of packet mode network –

connection oriented (CO) and connectionless (CL).

Comprises of packet switching exchanges (PSEs)

For CO, the connection is first set up utilizes only a

variable portion of the bandwidth of each link and

hence the connection is known as a virtual

connection or virtual circuit




Packet Mode

For CL, the establishment of a connection is not

required and the 2 communicating

terminals/computers can communicate and

exchange information as and when they wish.

In order to do this, each packet must carry the full

source & destination address in its header in order

for each PSE to route the packet onto appropriate

outgoing link.

In CL, PSE is normally known as router




Packet Mode

The service offered by a packet switched network is

best-effort service, depending of number of

packets in the output queue, there will be some

delays.

Router uses the store-and-forward method for

packets delivery

The overall mean transfer delay of the packet

across the network is know as mean packet transfer

delay.




Network QoS

The operational parameters associated with a communication

channel through a network as known as the network Quality of

Service (QoS) parameters and collectively they determine the

suitability of the channel for the user of a particular

application.

For circuit-switched network, the QoS parameters associated

with constant bit rate include:

The bit rate

The mean bit error rate (BER)

The transmission delay




Circuit-switched network

If the probability of BER is P and number of bits in

a block is N, then assuming random errors, the

probability of a block containing a bit error PB is

given by:

PB = 1- (1-P)N which is approx N X P (if N X P < 1)




Circuit-switched network




Packet-switched network

The QoS parameters associated with a packet-

switched network include:

The maximum packet size

The mean packet transfer rate

The mean packer error rate

The mean packet transfer delay

The worst-case jitter

The transmission delay (Tp = distance/speed)




Packet-switched network




Application QoS

Depending on types of application, the QoS

parameters include:

The required bit rate or mean packet transfer rate

The maximum startup delay

The maximum end-to-end delay

The maximum delay variation/jitter

The maximum round-trip delay




Application QoS




Summary

In this lecture, we have discussed:

The different types of media that are used in

multimedia applications

The different types of communication

networks that are used to support these

applications

A selection of the different types of

application


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