Download Lesson 6-2: History of Internetworking

Unit 6: Internetworking Outlooks
Lesson 6-2: History of Internetworking
At a Glance
A course in networking is about communication, the sharing of ideas,
information and messages with others. Specifically, it is about how people
use networks of interconnected computers to enable communications
between individuals, businesses and organizations. Advances in computer
technology satisfy the demand for better communication while at the same
time creating new demands. The high demand for new communications
technologies is creating large shifts in employment to create and sustain
this new “Information Age.”
Networking is not a new concept. From our earliest history, people have
needed to communicate across vast distances. As we study the evolution of
communication solutions, we will see that the concept of networking has
been in existence throughout history. It is the technology that has changed
and continues to change to meet demands.
What You Will Learn
After completing this lesson, you will be able to do the following:
•
Summarize the history of networking from the telegraph to modern
computer technology.
•
Describe the evolution of data transmission from Morse code to ASCII
standards.
•
Identify emerging technologies in networking.
•
Describe Unified Networks and how they will improve global
communications.
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Tech Talk
•
ASCII—American Standard Code for Information Interchange. A 7-bit
coding scheme that assigns unique numeric values to letters, numbers,
punctuation, and control characters.
•
Baudot Code—A 5-bit coding scheme used for transmitting data over
a printing telegraph.
•
ENIAC—Electronic Numerical Integrator and Calculator. This early
computer was developed for use by the US Government in 1946.
•
Ethernet—A local area network technology developed by DEC (Digital
Equipment Corporation), Intel, and Xerox in the early 1970’s.
•
Internet—The world’s largest network spanning the globe with it’s
origins dating back into the 1960’s.
•
Modem—Modulator-Demodulator. A modem converts between the
digital signals used by computers and analog signals to allow data
transmission over telephone lines.
•
Morse Code—A code of dots and dashes or long and short sounds used
to transmit messages over a telegraph.
•
RAMAC—Random Access Method of Accounting and Control. This
was the first hard disk developed by IBM in 1956.
•
Telegraph—An early communication device developed in the 1840’s
using an electromagnet connected to a battery via a switch. The device
has only two states, on or off. Morse code was developed to use the
device to transmit information.
•
Telephone—A communication device that electrically transmits sound
and voice. Alexander Graham Bell patented the telephone in 1876.
•
Teletypewriter—A printing telegraph that uses a typewriter style
keyboard. The teletypewriter uses a modified Baudot code instead of
Morse code.
•
Terminal—A terminal looks like a personal computer, but it cannot do
anything unless it is connected to a host computer
History of Early Networking and Computers
Networks have long been in existence facilitating communication over time
and space. Some of the earliest communications systems consisted of
smoke signals, drumbeats, and lantern beacons. The Egyptians developed
papyrus, one of the earliest forms of paper, to facilitate written
communication. In 1455, Johann Gutenberg invented the printing press,
revolutionizing written communication around the world.
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By 1789, the United States created the postal service using the mass
network of rail lines and roads to deliver messages across the country.
However, in the late 19th century, the territories of the United States
expanded beyond reliable roads and railways. In 1860, the firm of Russell,
Majors, and Waddell formed the Pony Express to decrease the delivery
time of mail over these new territories. The pony express service consisted
of a network of relay stations between Missouri and California, with 190
way stations to provide fresh horses to the riders. Each rider rode about 75
miles in the relay system.
The pony express ended with the completion of the overland telegraph
connections in 1861. With the birth of the telegraph in the 1840’s and the
completion of the overland connections, networking moved into the
electronic age.
The Telegraph and Morse Code
Recently coined the Victorian Internet, the telegraph was developed in the
1840’s, by Samuel Morse. Using an electromagnet connected to a battery
via a switch, the telegraph provided an electronic solution to
communication over large distances. Within the United States, the
telegraph lines followed the developing train tracks across the country.
There were over one million miles of telegraph lines across the country by
the early 1900’s. Telegraph cable was laid across the Atlantic in 1858 and
transatlantic service began in 1866.
The telegraph has only two states, on or off. When the switch is closed, the
electric current from the battery flows through the wire into a sounder at
the receiving end. When the switch is open, the electric current is shut off.
The Telegraph Moved Networking into the Electronic Age
Morse Code
Sending
Telegraph
Receiving
Telegraph
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Morse code was developed by Samuel Morse to use with the telegraph to
transmit information over wire. The length and pattern of the on and off
states of the telegraph are defined by Morse code into letters of the
alphabet and numbers. Long “on” states are called dashes and short “on”
states are called dots. The combinations of dots and dashes code for each
letter of the alphabet and numbers.
The Morse Code Standard for “Call For Help” was SOS
The Telephone
On February 14, 1876, Alexander Graham Bell filed for a patent for the
telephone. The telephone operates by changing sound waves into electrical
pulses. Every telephone has a transmitter (mouthpiece) and a receiver
(earpiece). Bell designed the telephone to use a membrane in the
transceiver that was attached to a rod with a coil of wire. Sound struck the
membrane, which moved the rod, causing the coil of wire to produce an
electrical current.
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Using Voice Transmission, Telephones Connect the World
This design has been improved over the years. However, the basic
technology of converting speech into electrical signals, transmitting the
signals over copper wire, and converting them back into speech is still an
important component of modern networking. Today’s telephone system
links the entire globe. With the addition of wireless telephones, the
limitations of the copper wire connections are eliminated, allowing
individuals to communicate via telephone from nearly anywhere (for
example, the car, the park, or the elevator).
The Teletypewriter and The Baudot Code
At the same time that the telephone was being developed, the world was
looking for a better communication technology. The telegraph was only
able to transmit one message at a time and it required an operator present
at both ends of the wire. The goal was to create a telegraph that was more
efficient and less costly.
Emile Baudot, in 1874, created a new coding system that allowed up to six
operators to share a single telegraph line. The Baudot code used a fiveunit scheme that represented every character. Unlike Morse code, the
electrical pulses created by the telegraph were of equal length. Baudot
also created a printing telegraph where perforations were made on a tape
corresponding to the code. An operator on the receiving end could then
interpret the tape.
Through the combination of the telegraph and telephone technologies, the
teletypewriter was created. Using an improved version of the Baudot code
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and the addition of a typewriter keyboard, an operator was able to type the
correct sequences of electrical impulses directly to the telegraph line. On
the receiving end, the teletypewriter was able to print the messages.
Often teletypewriters were connected in a round-robin circuit, allowing
information to be relayed across a network of teletypewriters. Messages
sent from the transmitting station were received along the network to the
next closest station. In turn, each operator relayed the message to the next
station, until the last station on the circuit received the message.
Since 1948, news services, such as the Associated Press, used the telegraph
and later the teletypewriter to report news from around the globe. In the
1980s, the speed of computer and satellite technology surpassed the speed
of wire services.
Teletypewriters Transmitted News from Around the World
World News Received from
the Associated Press
World News
Sent by the
Associated
Press
Check Your Understanding
♦ Networking is about communication. Explain how the pony
express, the telegraph, the telephone, and the teletypewriter
represent early networking.
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Early Computers
Early computers were very large machines called mainframes. They were
very slow and much more expensive compared to today’s computers, but
they performed essentially the same functions. They represented huge
improvements over previous manual methods of calculating and
manipulating data. In the late 1940’s and 1950’s, computers were used
only in government offices, and large corporations and institutions.
•
1944—Harvard University and IBM released the Mark I. Mark I was
powered by electromagnetic switches that could automatically do long
involved mathematical calculations.
•
1946—The U.S. government began using the ENIAC (Electronic
Numerical Integrator and Calculator). The ENIAC calculated the
trajectory of artillery weapons. It was powered by 18,000 vacuum tubes
and was very large and complex to operate.
•
1946—Bell Laboratories invented the transistor to enhance the speed
and efficiency of telephone systems. Transistors become faster as they
become smaller, and are more reliable than vacuum tubes. However,
transistors are sensitive to heat.
•
1954—Texas Instruments developed a silicon-based transistor that is
less costly and more resistant to heat.
•
1956—IBM introduced the RAMAC (Random Access Method of
Accounting and Control). RAMAC was the first hard disk and consisted
of 50 double-sided disks, two feet in diameter. RAMAC could only
access 5 MB of data.
•
1959—Texas Instruments developed a silicon wafer that combines
transistors, capacitors, resistors, and diodes.
Mainframes Were Enormous Compared to the PC
The
ENIAC
The PC
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Early Computer Networking
In the 1960’s, the teletypewriter was adapted for use in the computer
industry and communications satellites began to transfer telephone and
television signals between continents. New technologies and products
allowed mainframes to perform unrelated tasks for users from multiple
terminals. A terminal looks like a personal computer, but it can not do
anything unless it is connected to a host computer.
In 1962, Digital Equipment Corporation introduced the first time-share
terminal for mainframes and the first minicomputer. A time-sharing
system allows users at different terminals to use the same computer at the
same time. AT&T introduced the Bell 103 modem which allowed
mainframes and terminals to connect via telephone lines. The term modem
is derived from its functions as a modulator and a demodulator. A modem
converts between the digital signals used by computers and analog signals
to allow data transmission over telephone lines
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•
1966—The Baudot code was replaced with ASCII (American Standard
Code for Information Interchange). Unlike the Baudot code, ASCII
uses a 7-bit code and defines 96 printable characters. ASCII also
provided a validity test for received data.
•
1968—IBM patented the Dynamic Random Access Memory (DRAM)
which is a storage device for personal computers.
•
1971—Intel introduced the first microprocessor. Minicomputers were
developed to fill the need of smaller companies that could not afford to
purchase the large mainframes. Several applications such as word
processing became available.
•
1977—Apple Computers introduced the first personal computer, the
Apple II.
•
1981—IBM introduced their microcomputer called the Personal
Computer (PC). With this machine, the power of the computer was
brought to the desktop.
•
1984—Apple introduced the Macintosh computer during the Super
Bowl.
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Early Personal Computers
Apple
IBM
Desktop computers became the norm, however there was still a need to
share information from computer to computer. The need to share
information and resources led to the next step, local area networks using
transmission cables to connect computers together.
Check Your Understanding
♦ Briefly describe the differences between the Baudot code and ASCII.
What advantages does ASCII have over the Baudot code?
Ethernet
Robert Metcalfe of the Xerox Palo Alto Research Center (PARC) first
coined the name “Ethernet” in 1973. Prior to the introduction of Ethernet,
the University of Hawaii had developed a radio network for communication
between the Hawaiian Islands called the Aloha network. Within the Aloha
network, a workstation sent a transmission and then waited for an
acknowledgement. If no acknowledgement arrived, the workstation
assumed that another workstation had sent a transmission at the same
time and caused a collision between the two transmissions. The
workstations then retransmitted. This cycle continued until the
transmission was received at the destination and an acknowledgement was
received by the transmitting workstation.
Ethernet technology improved the Aloha system by the incorporation of a
new protocol called Carrier Sense Multiple Access with Collision Detection
(CSMA/CD). Within this protocol, the transmitting workstation listens to
the activity over the network before it transmits. The workstation can
detect collisions and Ethernet allows for multiple workstations to share a
channel in the network. Ethernet is the most popular local area network
technology due to the ease of installation, management, and
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troubleshooting. Currently, Ethernet technology allows for transmission
rates up to 1 Gigabits per second (Gbps).
•
1977—Robert Metcalfe received a patent on Ethernet.
•
1978—The patent for the Ethernet repeater was issued.
•
1980—Digital Equipment Corporation, Intel, and Xerox joined forces to
introduce the 10 megabit per second Ethernet called DIX Ethernet
standard.
•
1982—DIX Ethernet Version 2 was released.
•
1985—IBM’s Token Ring alternative was introduced as a new LAN
technology.
The Internet
The Internet is the world’s largest network, spanning the globe. Its origins
date back to the 1960’s. It consists of a super network of interconnected
government, education, and business networks.
In the 1960’s the U.S. Department of Defense (DOD) wanted a network
that would allow communications throughout the United States even if the
existing telecommunications lines were destroyed by enemy attack.
Funded through the DOD’s Advanced Research Projects Agency, a new
network was formed called ARPANet with only four computers, three
located in California and one in Nevada. ARPANet was limited by the fact
that different systems could not connect to each other. With funding from
military sources, the universities and government contractors continued to
improve on ARPANet.
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•
1973—Transmission Control Protocol (TCP) and Internet Protocol (IP)
emerged, allowing various systems to interconnect.
•
1975—The Defense Communications Agency became responsible for
ARPANet.
•
1979—Academic and research facilities were allowed to connect to
ARPANet leading to a rapid growth of the network.
•
1980—Tim Berners-Lee , a software engineer, developed HTML
(HyperText Mark-up Language) used in the World Wide Web.
•
1986—The National Science Foundation initiated their own high-speed
network called NSFNet that connected various r egional networks. The
term “Internet” was adopted.
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1988—MCIMail was given permission to connect to the Internet.
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1989—The graphical interface for the Internet called the World Wide
Web was proposed using HTML. CompuServe, ATTMail, and
Sprintmail connected to the Internet. ARPANet was dismantled.
•
1991—Tim Berners-Lee developed the HyperText Transfer Protocol
(HTTP) and introduced the WWW on the Internet.
•
1993—NSFNet began to be dismantled.
•
1999—Over 150 million people use the Internet/WWW each week.
Today the Internet is the largest interconnection of networks in the world.
The Internet allows communication and sharing of information between
users all over the world through the use of connected computers and an
extremely efficient technology called packet switching which moves huge
quantities of data around the world. It has grown to thousands of
interconnected networks with millions of users worldwide.
With the development of a graphical user interface for the World Wide
Web, more people can access the web with less training. The demand for
access has led to thousands of web servers linking the world to retail
stores, on-line databases, research resources, government publications,
public libraries, and more.
The Internet: The World’s Largest Network
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What’s Next?
“As new and existing network applications evolve to embrace highresolution graphics, video, and other rich media data types, pressure is
growing at the desktop, the server, the hub, and the switch for increased
bandwidth.” This statement from the Gigabit Ethernet Alliance sums up
the ever growing demands of our society for faster, more efficient, and
unified networks that will increase our productivity and yet reduce the cost
of networking.
Gigabit Ethernet
The typical local area network uses Ethernet technology that transmits
data across a network at the rate of 10 Mbps. However, Fast Ethernet,
approved in 1995, has become the newest choice in Ethernet technology.
The growing demand for Fast Ethernet for the workstation has led the
industry to conclude that even higher speed technology is needed as a
backbone supporting the networks.
Fast Ethernet gained popularity quickly because its implementation
required little, if any, structural changes, retraining of network managers,
or excessive additional costs. The same will hold true of Gigabit Ethernet.
Gigabit Ethernet (1000 Mbps) uses the same protocols as Ethernet and
Fast Ethernet. Now being implemented, the efficiency of the network
increases by a factor of ten with limited additional costs or retraining of
personnel.
Router Switching
Internetworking devices called routers and switches are used to make
“intelligent” decisions about data as it passes through an Ethernet
network. There are advantages and disadvantages of using either of these
devices.
•
Switches
−
−
Advantages:
−
Layer 2 switches direct transmissions to specific workstations,
rather than forwarding to all workstations, thus relieving
congestion on the network.
−
Switches operate faster than a router and are easier to install
and operate.
Disadvantages:
−
•
Routers
−
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Switches are not used to link different types of networks.
Advantages:
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−
−
A router receives packets (data) and selects the optimum path to
forward the packet across the network.
−
Routers also learn the addresses of the interconnected networks,
which allows for larger, more complicated networks.
−
Routers can connect different network types such as Ethernet
and wide area networks.
Disadvantages:
−
Routers are difficult to configure and require special routing
software.
A new class of networking device, the routing switch, is revolutionizing the
performance of internetworks. By combining the two technologies into one
device, a network gains flexibility, increased performance and greater
support for advanced applications.
Unified Networks
“Since the invention of the telephone, almost every civilian
communications network has been based on the concept of circuits.”
(Schiesel, 1999) The telephone system has been based on a system of
circuit-switched networks that allow users to communicate over a
dedicated line for as long as needed. The network stays open until the user
disconnects, even if there are times when no data (i.e. conversation) is
being transmitted. While the circuit is open, no one else can use that
circuit and costs accrue even when no data is being sent.
Circuit switching is often used for the exchange of information between
computer networks. The system works much the same way, the connection
or circuit between your computer, the switch and the network remains
open, costs accrue, and no one else can use the circuit while the circuit is
open even when no data is transmitting.
The Internet uses another technology called packet switching, which
breaks long messages into smaller, multiple packets for transmission
across the most logical and efficient pathway. The packets are then
reassembled at the receiving end. This allows more than one computer to
transmit data over the wire at a time. Packet switching is faster and more
efficient than circuit switching.
Today, these technologies are becoming unified into one infrastructure
erasing the lines between computers and telephony. Unified networks
bring together many different types of products and technologies, including
circuit and packet; switching and routing; optical, wireline, and wireless
transmission, using a single management system.
The Internet is changing how we communicate, how we relate to one
another, and even how we live and do business. With unified networks,
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call centers over the Internet are emerging to increase the interaction
between businesses and their customers. Customers will pull up a web
page and click a button to call a business to place an order or request other
services, without leaving the Internet session or dialing a number.
Voice, data, and video will be unified into one network of efficiency and
speed.
Unified networks will revolutionize the way we communicate.
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Try It Out
Discovering Morse Code
Practice sending a message in Morse code and reflect on your experience.
Materials Needed
•
Internet connection
•
Word processing application
•
MRX Morse Code Freeware downloaded and installed from
http://www.mrx.com.au/d_morse.htm
Instructions:
1. From the Start Menu, open the Programs folder and then open the
MRX folder.
2. Select the MRX program to begin the program.
3. A pop-up log-in box will appear. Type your name in the box and click
OK.
4. The MRX menu bar will appear. Select the “Transmit a text file as
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5. The Morse Attributes selection box will appear. Select “Custom” in the
Morse type area.
6. The Morse Practice file will show up in the list to the left. Select the
Morse Practice file and click OK.
7. The Morse Transmit practice box will appear. The practice text that
you will attempt to transmit in Morse code will appear in the top box.
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8. Using the DOWN arrow key and the chart below, type the practice text.
As you type, you will hear the Morse sound and the actual letter you
typed will appear in the bottom box.
Morse
Code
Letter
Morse Code
Letter
A
.-
N
-.
B
-…
O
---
C
-.-.
P
.--.
D
-..
Q
--.-
E
.
R
.-.
F
..-.
S
…
G
--.
T
-
H
….
U
..-.
I
..
V
…-
J
.---
W
.--
K
-.-
X
-..-
L
.-..
Y
-.--
M
--
Z
--..
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9. The results of your practice coding will appear in the box below the
Morse Transmit Practice box.
E F AA O P I E
10. While you are practicing Morse code, another information box, called
MRX Status, will appear indicating to you how many words per minute
(WPM) you are typing.
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11. When you have completed your practice session, or when your teacher
says it is time to stop, make a print screen of the active windows (the
MRX Status box and the Morse Transmit box) and paste each screen
into a Word document. Follow these steps to capture the active
windows and paste them into a Word document:
a. Select the window (the box) you want to copy first.
b. Press the Keys: ALT+Prnt Scrn.
c. Open a new document in your word processor (MS Word, etc.).
d. Select the Edit menu and then select PASTE. Your screen capture
will appear in the new document.
e. Repeat the process to capture the next active window and paste it
into your document.
12. Once you have your screens pasted into your word document, you can
use them to illustrate how well you did practicing Morse code.
13. Write a description of your experience using Morse code. Include in
your description, the difficulties, frustrations, successes, and tricks you
discovered to increase your efficiency and accuracy.
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
Participation, persistence, and accuracy
25
Quality analysis leading to solutions which
increase accuracy and speed
50
Thoughtful description of experience
25
TOTAL
Your Score
100
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Stretch Yourself
Timeline
Materials Needed
•
None
1. Develop a time-line of the evolution of modern computers, including the
names and dates of each major event.
2. Based on outside research, add other relevant milestones in history
that correspond to the same time periods.
3. Add personal events such as when you were born and when you got
your first computer, and so on.
4. Illustrate your time line with quality drawings, personal photos, and
pictures collected from your resources.
5. Cite your resources. Add to your portfolio.
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
On-time delivery of assignment
10
Citation of resources
15
Quality timeline suitable for reproduction
25
Accuracy blended with creativity
50
TOTAL
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Your Score
100
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Network Wizards
The Victorian Internet by Tom Standage
1. Read Tom Standage’s book, The Victorian Internet. This is an excellent
book that outlines the development of the telegraph and compares it to
the development of the Internet.
2. Research the development of the Internet and the World Wide Web. Do
not only look at dry facts, but dive into the lives, frustrations,
motivations, successes, and failures of the people and organizations
that contributed to the creation of the Internet and WWW.
3. Write a thesis paper defending or rejecting Mr. Standage’s opinion that
the development of the telegraph parallels the development of the
Internet and the WWW. Include effects of both “internets” on world
economy, social issues, and crime.
4. The paper must have a thesis statement, logical arguments defending
the thesis statement, and cited resources supporting your thesis.
5.
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
On-time delivery of assignment
10
Organization, spelling, grammar
15
Citation of supporting resources
25
Quality thesis statement with supporting
arguments
50
TOTAL
Your Score
100
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Summary
In this lesson, you learned the following:
•
The evolution of networking from the telegraph to modern computer
technology
•
The evolution of data transmission from Morse code to ASCII
standards.
•
The identification of future technologies in networking.
•
The description of Unified Networks and how they will improve global
communications.
Review Questions
Name_______________
Lesson 6-2: History of Internetworking
Part A
1. Diagram a simple timeline of the history of networking and write a
summary about the milestones in networking history from the
telegraph to modern computers.
Part B
1. In a short essay, describe Morse code, Baudot code, and ASCII code.
Indicate in your essay the advantages of each code over the previously
used code.
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Part C
Place an “X” next to emerging technologies and an “O” next to existing and
legacy technologies.
1.
Teletypewriters
2.
Circuit switching
3.
Unified Networks
4.
Gigabit Ethernet
5.
Telephones
6.
Baudot code
7.
Internet Call Centers
8.
Switches
9.
Ethernet
10.
Personal computers
11.
Router-switches
12.
Telegraph
13.
Modems
14.
World Wide Web
15.
Routers
Part D
1. Describe the concept of Unified Networks and how they will improve
global communications.
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Scoring
Rubric: Suggested Evaluation Criteria and Weightings
Criteria
%
Part A: Summarize the history of networking
from the telegraph to modern computer
technology
50
Part B: Describe the evolution of data
transmission from Morse code to ASCII
standards.
25
Part C: Identify three emerging technologies
in networking.
15
Part D: Describe Unified Networks and how
they will improve global communications.
10
TOTAL
100
Try It Out: Practice and reflect on Morse Code
100
Stretch Yourself: Timeline of Computer
Evolution
100
Network Wizards: Historical Research and
Analysis
100
FINAL TOTAL
400
Your Score
Resources
Bay Networks. (1998). Internetworking Fundamentals, Bay Networks,
Inc., Billerica, Massachusetts.
Derfler, Jr., Frank J., & Freed, L. (1998). How Networks Work, Fourth
Edition. Macmillian Computer Publishing/Que Corporation, Indianapolis,
Indiana.
Gigabit Ethernet Alliance. (1997). Gigabit Ethernet: Accelerating the
Standard for Speed. On-Line. Available: http://www.gigabit-ethernet.org.
Meeker, M. & DePuy, C. (1996). The Internet Report. HarperCollins
Publishers, Inc., New York, New York.
MRX Software. MRX Morse Code V1.
http://www.mrx.com.au/d_morse.html
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Schiesel, Seth. (1999). AT & T’s Enbrace of New Technology Signals Next
Era. The New York Times on the Web. On-line. Available:
http://www.nytimes.com/library/tech/99/03/biztech/articles.
Spurgeon, Charles E. (1997). Practical Networking With Ethernet,
International Thomson Computer Press, Boston, Massachusetts.
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