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Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 1
Business Data Communications
Chapter One
Introduction to Data Communications
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 2
Changing our World
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 3
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 4
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 5
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 6
1960s – Digitization of Data
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 7
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 8
1970s – Growth of Data Communications
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 9
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 10
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 11
1990 – Internet as Common Tool
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 12
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 13
2000s – Pervasive Computing
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 14
Acme’s use of Telemetry
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 15
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 16
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 17
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 18
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 19
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 20
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 21
The OSI Layers
Application Presentation Session Transport Network Data Link Physical
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 22
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.
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 23
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 24
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
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 25
A Local Area Network
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 26
A Possible Backbone Network
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 27
A Metropolitan Area Network
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 28
A Wide Area Network
Business Data Communications, by Allen Dooley, (c) 2005 Pearson Prentice Hall Chapter One 29
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