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DATADATACOMMUNICATIONCOMMUNICATION

Lecture-1

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Textbook

Data Communications and Networking

2nd Edition by Behrouz A. Forouzan

Data and Computer Communication 6th

Edition by William Stallings

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Overview of Lecture 1

Data Communication

Brief History of CommunicationData Communication System

Key Data CommunicationTerminology

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DATA COMMUNICATION

Data Communication is the

exchange ofInformationfrom one entity to the other

using a TransmissionMedium

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Data Communication Definition

(Modified)

Data Communication is the exchange

of data (in the form of 0s and 1s)between two devices (computers) via

some form of the transmissionmedium.

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LOCAL and REMOTE

CommunicationLOCAL

Communicating devices arepresent in the same building or asimilarly restricted geographical

area

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Data Communication System

For Data Communication to occur,

communicating devices must be a

part of a system made up of somespecific kind of hardware and

software. This system is known as

DATA COMMUNICATION SYSTEM

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Effectiveness of Data Comm.

System

Effectiveness depends upon three

fundamental characteristics:

Delivery

Accuracy

Timeliness

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Components of a Simple Data

Communication System

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Components of a Data

Communication System A Data communication system is

made up of 5 components:

Message Sender

Receiver Medium

Protocol

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Transmission Media

Medium Speed Cost

Twisted Wire 300bps-10Mbps Low

Microwave 256Kbps-100Mbps Low

Coaxial Cable 56Kbps-200Mbps Low

Fiber OpticCable

500Kbps-10Gbps High

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EXAMPLE Electronic Mail

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A Complex Data Comm.

System

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Suggested Reading

Section 1.2, Data Communications andNetworking 2nd Edition by Behrouz A.

Forouzan

Sections 1.1, 1.2, Data and Computer

Communication 6th Edition by WilliamStallings

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Key Data Communication

TerminologySession: communication dialog between

network users or applications

Network: interconnected group of computers

and communication devices

Node: a network-attached device

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Key Data Communication

TerminologyLink: connects adjacent nodes

i.e. wire, cable. Any thing that physical connects.

Path: end-to-end route within a network

Circuit: the medium over which datatravels

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Key Data Communication

TerminologyPacketizing: dividing messages into

fixed-length packets prior to transmission

over a networks communication media

Routing: determining a messages pathfrom sending to receiving nodes

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Network

A Network is a set of

devices (Nodes) connectedby Communication Links

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Networks- Why we need Them?

Point to point communication

Devices are too far apart

Large set of devices would need

large number of connections

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Networks- Why we need Them?

Solution is to connect all devices to acentral system known as a

NETWORK

Two Main Classes of Networks

Local Area Networks (LANs)

Wide Area Network (WANs)

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Distributed Processing

Instead of a single large

machine being responsible forall aspects of a process, each

separate computer handles asubset of the task

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Advantages of Distributed

Processing

Security

Distributed Data bases

Faster Problem Solving

Security through Redundancy

Collaborative Processing

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Network Criteria

Data

CommunicationNetwork Criteria

Performance Reliability Security

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Network Criteria

Performancecan be measured in Transit and Response Time

Number of UsersType of Transmission Medium

Hardware

Software

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Network Criteria

Reliability

Frequency of failure

Recovery Time after Failure

Catastrophe

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Network Criteria

Security

Unauthorized Access

Viruses

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Network Applications

Marketing and Sales

Financial Services

Manufacturing

Electronic Messaging

Teleconferencing

Cable Television

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Suggested Reading

Section 1.3, Data Communications andNetworking 2nd Edition by Behrouz A.

Forouzan

Sections 1.3, Data and Computer

Communication 6th Edition by WilliamStallings