Session Eleven:
The Internet

Lecture Notes

Lecturette 11 - The Internet

In early September 1969, soon after Woodstock and the first lunar landing, the Internet was created and tested.  The first transmission, linking computers at the Pentagon with university computers in California, lasted only a few seconds.  But it worked.

The idea of connecting computers to transfer data was a fairly radical notion.  At that time, all computers were mainframes.  The keyboard was not yet an input devise and the mouse had yet to be invented.  The fourth generation computer brought up that summer at the University of Illinois – the nation’s newest and most powerful – boasted 64 kilobytes of random access memory.  Input was through a reel to reel tape drive or from “IBM’ cards containing 88 columns of data with 48 possible entries for each column.

At first, universities opposed connecting computers.  Time on computers – there were few and there was a great demand for them – was precious, and the management of computer time through “time sharing” was the standard practice.  The idea that one would freely share the information one one’s computer with others seemed to threaten an important revenue source.  Yet the need to access another database soon became apparent.  In the space program, for instance, astronauts had spent hours checking lines of binary code for input to calculate reentry.  The laborious process was risky, for the more times input was keyed, the greater the likelihood of error and, as the saying of the day went, “Garbage in” meant “garbage out.”

For more than twenty years, the Internet remained the province and toy of academics.  Needed long lines of code to access, fragile in connection, and precluded by the National Science Foundation from commercial application, the Internet might have remained merely a sophisticated, electronic “sandbox” or toy for the academic community.  Its primary use or “killer application” was—and remains, electronic mail, the transfer of text composed by one user and sent to another.

Breakthroughs in critical enabling technologies, particularly in software, made it increasingly robust and easier to use.  By 1995, the Internet became the “In” thing to do for owners of personal computers.  Surfing the ‘net became easy, and literally millions got online.

When you access the Internet, here is what happens.  First, your modem uses the public switched telephone network to access your Internet Service Provider, or I.S.P.  The ISP may use the services of one or more Network Service Providers, NSP’s to transfer the packets of information contained in your message to a Network Access Point.  At this NAP, you actually go onto the Internet infrastructure.  Your packets of information are routed across the net to the server of your choice.

There are only five network access points in the United States – Virginia, New Jersey, Illinois, California, and Georgia are the locations.  All traffic bound for the net must enter at one of these points.  Routing to them is a major market for the telecommunications companies.  Many also function as network service providers, leasing fiber and wire to trunk to the access points.

The signal you send via your modem divides your data into “packets”.  Each of these packets is individually addressed to the receiving address using TCP/IP – Transfer Control Protocol/Internet Protocol.  This TCP/IP is a three layered addressing system that ensures packets are routed to the right end location.  Your domain name and screen name are merely mnemonic devices to make it easier to remember and use addresses.  Underlying those names are a series of numbers, assembled in four sets (soon to be five) which function largely as a telephone number does, to identify the other end of the transfer.

But unlike a regular circuit switched telephone call, packet switches transfer packets.  This division increases the efficiency of the network.  In a circuit switched call, the circuit must be open continuously from end to end.  In a packet switched network, users share the lines.  The circuits are known as "virtual" circuits because of the sharing of the lines.  When you sit with your screen idle, there is no connection—your are seeing the last graphic loaded, perhaps from your cache or C drive.  When you click your mouse to go to another site or to send or receive data, you send your packets via the bast available route to the computer at the other end.

But if you are connected to your ISP through a dial-up connection, you do have a circuit operating continuously.  This creates a problem for the local exchange telephone company. Since their switch is designed to an average call duration of about 7 minutes, and since most ISP connections average more than 28 minutes, they are suffering form a congestion problem of the first order.  You may have experienced a similar problem administering a corporate network.

The current technological solution is to shunt calls around the central office switch.  Since April 1999, Bell Atlantic has used a Lucent application called “virtual switching” to identify and transfer calls originating at a modem and terminating at an ISP. Note: there is a difference between a virtual circuit and a virtual switch. The virtual switch allows the call to be treated as a packet switch call from origin to termination without tying up a circuit.  Further, it eliminates the need to digitize the call at the central office.  The digitization occurs art the modem, so the entire throughput is in packets.

This is a major change for the telephone companies.  When packet switching was first proposed, the Bell System rejected it as unnecessary and undesirable.  They acknowledged the efficiency of packet switching, but the incentive was to increase the number of minutes of use, not economically rationalize the network. 

During the 1980’s, the critical technologies of personal computers, modems, hubs and routers were developed, refined, and deployed.  Companies such as Sun Microsystems and Cisco emerged from “nowhere” to become powerhouses in the newly emerging packet communication industry.  Two critical software developments made it possible to access remote data bases quickly and efficiently.  The first, hypertext transmission protocol and hypertext transmission markup language were developed at the Swiss-based laboratory CERN by Tim Berners-Lee.  This language allowed jumps from the data base one was accesses to another one laterally based upon a “hyperlink”.  You recognize these terms at the familiar “http://” and as html.

Still, it remained to put the graphics together.  In a burst of creative activity and energy from November 1992-March 1993, an undergraduate at the University of Illinois, Marc Andreeson, developed a program called “Mosaic” which became the first browser.  Successfully marketed within the year as “Netscape” this browser became the critical technology for allowing nontechnical people to easily and quickly use the Internet.  Within two years, Internet use grew from a few thousand to millions of end users. Current growth is calculated at doubling every 100 days.  There are currently an estimated 250 million Internet users globally, with more than half in the United States.

In 1995, Congress altered the law governing Internet use, making it legal for the first time to provide commercial services.  E-commerce took off.
 

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