itgd4103 data communications and networks lecture-1 dr. anwar mousa university of palestine faculty...

ITGD4103 Data Communications and Networks

Lecture-1

Dr. Anwar Mousa

University of PalestineFaculty of Information Technology

Dr. Anwar M. Mousa [email protected]

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DATE TOPICSWeek 1 Course introduction-Data Communications

Week 2 network models

Week 3 Data and signals

Week 4 Data Transmission Techniques

Week 5 Digital and Analog Signals

Week 6 Bandwidth Utilization and multiplexing

Week 7 Transmission Media

Week 8 Mid-Term Exam

Week 9 Wired LANs: Ethernet

Week 10 Wireless LANs

Week 11 Wireless WANs

Week 12 SONET/SDH

Week 13 Frame Relay

Week 14 ATM

Week 15 Switching

Week 16 FINAL EXAM


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Provide an overview of data communication theory

Provide a basic understanding of networking and

telecommunications.

Consider the impact and implications of new

communications technology systems.

Describe the roles of switching, transmission, and

signaling in providing telecommunications services.

Course Objectives


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COURSE OUTLINE

EE 541/451 Fall 2006 [5]

Instructor InformationInstructor Information

Office location: Office hours: Email: [email protected] Phone: Research interests:

EE 541/451 Fall 2006 [6]

Textbook and SoftwareTextbook and Software

Require textbook: “Data Communications and Networking,” Behrouz A. Forouzan, 4th ed,

Mc-Graw Hill, 2007.

Reference“Data and Computer Communications,” W. Stallings, 7th ed., Prentice Hall,

2004.

EE 541/451 Fall 2006 [7]

Homework, Project, and ExamHomework, Project, and Exam

Homework 1 assignment per week

Exams Two exams: Midterm and Final

Participations Attendance and Feedback

EE 541/451 Fall 2006 [8]

Teaching StylesTeaching Styles

Slides plus White board Slides can convey more information in an organized way Whiteboard is better for equations and prevents you from

not coming. Course Website

Print handouts with 3 slides per page before you come Homework assignment and solutions

Feedback Too fast, too slow Presentation


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Introduction

to

Data Communications

Chapter OneChapter One


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What is Data Communications?

Data communications are the exchange of data

between two devices via some form of transmission

medium.

For Data communications to occur, the

communicating devices must be part of a

communicating system made up of a combination of

hardware (physical equipments) and software

(programs).


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The effectiveness of data com. system

The effectiveness of data com. System depends on

four fundamentals:

1. Delivary

Data must be received only by the intended device or user

only

2. Accuracy

Deliver data accurately (error-free)


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The effectiveness of data com. system

3. Timeliness

Deliver data without significant delay

4. Jitter

Jitter refers to the variation in the packet arrival time.


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Components

A data com. system has five components:

Message

Sender

Receiver

Transmission medium

Protocol


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Data RepresentationInformation today comes in different forms such as:

Text Text is represented as bit stream (0 or 1). The

prevalent coding system is called UNICODE,

which uses 32 bits to represent a symbole or

character used in any language.

The American Standard Code for Information

Interchange (ASCII) constitutes the first 127

characters in UNICODE.


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Data Representation Numbers

The numbers are directly converted to a binary

number to simplify mathematical operations.

Images An image is composed of a matrix of pixels where

each pixel is a small dot.

An image can be divided into 1000 pixels or more

(better resolution).

Each pixel is assigned a bit pattern.

For an image made of only black and white dots


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Data Representation A 1-bit pattern is enough to represent a pixel.

If an image is not made of a pure black and pure

white pixels, you can increase the size of the bit

pattern to include gray scale.

For example, to show four levels of gray scale, you

can use 2-bit pattern: A black pixel represented by 00, a dark gray by 01, a light

gray by 10 and a white pixel by 11.


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Data Representation To represent color image, one method is called

RGB, where each color is made of three primary

colors: red, green and blue.

The intensity of each color is measured and a bit

pattern is assigned to it.

Audio Audio is different from text, numbers or image.

It is continuous not discret.


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Data RepresentationInformation today comes in different forms such as:

Video Video can either be produced as a continuous

entity (by a TV camera) be a combination of

images, each discret entity arranged to convey the

idea of motion.


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Communications Channels A communications channel is a pathway over which

information can be conveyed.

It may be defined by a physical wire that connects

communicating devices, or by a radio, laser,o or other radiated energy source that has no obvious

physical presence.

Information sent through a communications channel has a

source from which the information originates, and a

destination to which the information is delivered.


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Communications Channels Although information originates from a single source, there may be

more than one destination,

o depending upon how many receive stations are linked to the

channel and how much energy the transmitted signal possesses.

In a digital communications channel, the information is represented

by individual data bits, which may be encapsulated into multibit

message units.

o A byte, which consists of eight bits, is an example of a message

unit that may be conveyed through a digital communications

channel.


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Communications Channels, cont... A collection of bytes may itself be grouped into a

frame or other higher-level message unit.

Such multiple levels of encapsulation facilitate

the handling of messages in a complex data

communications network.

The message source is the transmitter, and the

destination is the receiver.


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Communications Channels, cont… A channel whose direction of transmission is

unchanging is referred to as a simplex channel. o For example, a radio station is a simplex channel

because it always transmits the signal to its listeners and never allows them to transmit back.

A half-duplex channel is a single physical channel in which the direction may be reversed. o Messages may flow in two directions, but never

at the same time, in a half-duplex system.


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Communications Channels, cont… o One party speaks while the other listens. After a

pause, the other party speaks and the first party listens. Speaking simultaneously results in garbled sound that cannot be understood.

A full-duplex channel allows simultaneous message exchange in both directions. It really consists of two simplex channels, a forward channel and a reverse channel, linking the same points. o The transmission rate of the reverse channel may

be slower if it is used only for flow control of the forward channel.


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Any communications channel has a direction associated with it:


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Simplex One way communication only


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Half-duplex One way at a time.


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Full-duplex Communication in both directions simultaneously.


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Networks A network is a set of devices (nodes) connected by com.

Links.

Most networks use distributed processing, in which a

task is divided among multiple computers.

Network criteria

Performance

Transit time

Response time

Throughput


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Networks criteria

Reliability Accuracy of delivery

Frequency of failure

network’s robustness in a catastrophe

Security Protecting data from unauthorized access

Protecting data from damage

Recovery from breaches and losses

itgd4103 data communications and networks lecture-1 dr. anwar mousa university of palestine faculty...

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