business data communications, by allen dooley, (c) 2005 pearson prentice hallchapter one 1 business...

Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 1

Business Data Communications

Chapter One

Introduction to Data Communications


Changing our World


Primary Learning Objectives

Identify five data communications phases Understand the importance of protocols and

standards Be familiar with the OSI and TCP/IP networking

models Describe the benefits of a layered architecture Recognize the general categories of networks


Five Data Communications Phases

1960s - Digitization of Data

1970s - Growth of Data Communications

1980s - An Era of Deregulation

1990s - The Internet as a Common Tool

2000s - Pervasive Computing


1960s – Digitization of Data

Digitization transcribes data into binary form

First large-scale, mainframe computer systems are proprietary and they use a closed architecture technology

The trend today is for open architecture technologies


1960s – Digitization of Data


1970s – Growth of Data Communications

With greater frequency, businesses automate their previously manual processes, using computer technology

As a result, computers become more prevalent Increasingly, computers need to communicate

with each other so that their data and resources can be shared

Data communication infrastructures evolve in response to this need, particularly packet-switching networks


1970s – Growth of Data Communications


1980s – An Era of Deregulation

Initially, the telecommunications industry in the United States runs as a monopoly under Bell Telephone/AT&T

In 1984, the United States deregulates long distance telecommunication resulting in the breakup of Bell Telephone/AT&T

Deregulation’s intent is to provide greater competition in a given market


1990 – Internet as Common Tool

In 1969, ARPA evolves into ARPANET, which eventually evolves into today’s Internet

IPv4, the original protocol version for the Internet

Not designed with multimedia data in mind Today, hundreds of millions of people

worldwide connect to the IPv4 Internet IPv6, the latest version of the Internet, will

gradually replace IPv4


1990 – Internet as Common Tool


2000s – Pervasive Computing

Pervasive Computing A technology so commonly used it can be taken for

granted Essential to future pervasive computing will be

wireless technologies For example, telemetry allows the wireless

transmission and reception of data for monitoring equipment and environmental conditions


2000s – Pervasive Computing


Acme’s use of Telemetry


Data Communications

Currently a subset of telecommunications, although the differences are beginning to blur

Telecommunications includes television, telegraphy, and telephony

Data communications focuses primarily on the transmission of data between computing devices

0110010101110001010101


Encoding Schemes

Data is transmitted using binary encoding schemes

Binary encoding schemes, of which there are several, use the binary digits 0 and 1

A new binary encoding scheme called Unicode will allow for the encoding of more than 64,000 unique characters

Traditional encoding schemes, such as EBCDIC and Extended ASCII, allow for only 256 unique characters


Protocols

Data communications also depend on protocols

Protocols determine the rules for how something is performed or accomplished

Protocols become established or defined through a standards process


Standards

Standards may be formal or informal Informal standards are also called “de facto”

standards Standards can be proprietary or open The trend is toward open standards There are numerous standard-setting bodies

ISO, ANSI, IEEE, IETF, to name a few


Networking Models

Models are logical and based on theory In data communications, two important models

are: OSI – Open Systems Interconnection TCP/IP – Transmission Control Protocol/Internet

Protocol The OSI and TCP/IP models are both open

system models that use a layered architecture The OSI has seven Layers The TCP/IP has four or five layers, depending on

the source


The Layering Approach

In a layered model, each layer is responsible for specific functions

A layer must be able to communicate with the layer immediately above or below it

However, a layer does not have to “understand” how a layer above or below works

Designers of networking technologies can create products that function within a specific layer


The OSI Layers

Application Presentation Session Transport Network Data Link Physical


The TCP/IP Layers

Application

Transport Network Data Link Physical

The application layer of the TCP/IP model includes the application, presentation, and session layers of the OSI model.


OSI and TCP/IP

These models have several similarities Both offer layered architectures Both are open models They have similar data link layer functions They have similar physical layer functions Of the two, TCP/IP is the older and the more popular


Networks

Standards and protocols are critical in data communications when creating a network

Networks have four general classifications Local Area Network – LAN Backbone Network – BN Metropolitan Area Network – MAN Wide Area Network – WAN

Networks are based on models


A Local Area Network


A Possible Backbone Network


A Metropolitan Area Network


A Wide Area Network


In Summary

Data communications is a multifaceted field Many technologists end up specializing in specific

areas

Many standard-setting bodies affect its direction

Pervasive computing will transform how the average person uses and experiences data communications technology

business data communications, by allen dooley, (c) 2005 pearson prentice hallchapter one 1 business...

Documents

data communications

multimedia data

s digitization of data

allen dooley

pearson prentice hall

pearson prentice hallchapter

s digitization

ipv4 slide