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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. ST0025803A 425 Lesson 6-2: History of Interneworking 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. 426 ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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 ST0025803A 427 Lesson 6-2: History of Interneworking 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. 428 ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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 ST0025803A 429 Lesson 6-2: History of Interneworking 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. 430 ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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 ST0025803A 431 Lesson 6-2: History of Interneworking 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 432 • 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. ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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 ST0025803A 433 Lesson 6-2: History of Interneworking 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. 434 • 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. • 1988—MCIMail was given permission to connect to the Internet. ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks • 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 ST0025803A 435 Lesson 6-2: History of Interneworking 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 − 436 Switches are not used to link different types of networks. Advantages: ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks − − 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, ST0025803A 437 Lesson 6-2: History of Interneworking 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. 438 ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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 ST0025803A 439 Lesson 6-2: History of Interneworking 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. 440 ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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 --.. ST0025803A 441 Lesson 6-2: History of Interneworking 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. 442 ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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 ST0025803A 443 Lesson 6-2: History of Interneworking 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 444 Your Score 100 ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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 ST0025803A 445 Lesson 6-2: History of Interneworking 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. 446 ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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. ST0025803A 447 Lesson 6-2: History of Interneworking 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 448 ST0025803A Internetworking Fundamentals Unit 6: Internetworking Outlooks 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. ST0025803A 449 Lesson 6-2: History of Interneworking 450 ST0025803A Internetworking Fundamentals