'Net Structure/Users/History

Computer Networking:
What Is the Internet and Where Did It Come From?
Where the Heck Is Cyberspace?

A network of networks

• Little electronic packets of information or data are thrown around from one computer to another, around the world.
  • TCP/IP (Transmission Control Protocol/Internet Protocol)
  • Travelling from smaller networks to bigger and bigger ones
    • The connections between the biggest networks are called backbones
      • E.g., One Internet provider is BBNplanet, whose network looks like this:
        
      • Another large Internet Service Provider (ISP) is UUNET, whose backbone looks like this:
        
  • How do data packets find their way around these networks?
    • Each machine has a unique IP address, four numbers strung together
      • No other computer has this number.
        • E.g., 130.160.171.125
      • Read left to right = increasingly specific
        • 130.160 = U of Alabama network
        • 171 = College of Comm. network
        • 125 = specific machine in Phifer
    • Domain names
      • Easier to remember names may be attached to these numbers
        • E.g., www.tcf.ua.edu = 130.160.171.125
          • Read right to left = increasingly specific
          • edu = educational instutition
          • ua = the U of Alabama
          • tcf = TCF Dept.
          • www = the Web server machine in room 430C Phifer
        • Other abbreviations
          • gov (government), org (non-profit organization), net (organization associated with running the Internet), mil (military), and country codes (ca = Canada, uk = United Kingdom, br = Brazil)
      • How are these names attached to these numbers?
        • Certain computers function as Domain Name Servers (DNS)
          • When asked, they "serve" up the number associated with a name
          • E.g., at UA, ns1.ua.edu (130.160.4.4) is one of several DNS machines
        • When you type an address into a browser in the Lab it:
          1. Asks ns1.ua.edu for an IP number to go with the name
          2. Sends a request to that IP number for some data packets
          3. The distant computer notes your IP number and ships packets in that direction
      • Who controls the assignment of these domain names?
        • InterNIC, a company in Virginia--but this changed recently
        • Now, many companies can register domain names.
    • Tracing a data packet around the Internet
      • Traceroute (on a Unix machine), or tracert (on Windows), or dressed-up versions of the same such as Neotrace
      • E.g., here's the route a little data packet took from Tucson (and my Earthlink account) to Tuscaloosa, AL:
        
        Click here for detailed node information.
        
    • Checking how busy the Internet is.
      • For an indication of how fast it's working right now, see
        
        Higher numbers (out of 100) signify a faster 'Net connection.
• Client-Server model controls many of the Internet services.
  • One computer (the server) stores data and waits to be contacted.
  • Another computer (the client) contacts that computer and requests data.
  • If the server and the client understand the same protocol and can talk to one another, then the server will send the data to the client.
    • A protocol is similar to a language.
    • Both parties in a client-server transaction must speak the same language for it to succeed.
  • Client-server transactions work much like a restaurant.
    • A diner (the client) will request food (data) from the server (the server!).
    • The server then transports the food from the kitchen, where it's stored, to the diner.
    • Tip is optional.
  • E.g., a Web server sends data to a Web client (aka, browser) when it is requested.

How big is the World Wide Web--which runs through the Internet?

• 2.8 million sites
• 800 million pages
  • Of which search engines cover, at best, 16%.
    
• 15 terabytes of data
  • 1 terabyte = approximately 1 trillion bytes
  • 15 terabytes includes data for Web mechanics; actual text is closer to 6 terabytes
    • 6,000,000,000,000
    • (After removing HTML tags, comments, and extra whitespace.)
    • By comparison, a typical harddrive today in a home PC might hold 5 megabytes or approximately 5,000,000
    • Over a million (1,200,000) such home PCs would be needed to store all the text on the Web.
• 180 million images

What's on all those 800 million pages?¹

• 83% commercial content--remaining pages:
  
  • 6% scientific/educational content
  • 1.5% pornographic content
  • (Sites may have multiple classifications.)

Internet Users

How many people are "on" the Internet? Who are they?

Nobody really knows for sure.

• But some agencies are willing to make estimates in specific areas:
  • RelevantKnowledge: May 1999 survey
    • Web users in the U.S. (home and office) = 61.9 million
    • Households with computers = 50 million (click here for more info)
    • Households with modem access = 37.7 million
  • 
    Graphic, Visualization, & Usability Center (Georgia Tech): Web-based survey conducted October 10 through December 15, 1998
    
    
    
    
    • Provides more demographic information
      1. Found a higher percentage of men: 66.4% over all. An interesting split by Internet experience--with 'Net novices evenly divided between men and women:
         
         This finding is borne out by a Pew Research Center study in winter 2000:
         46% of 'Net users are women
         
      2. And also includes questions such as race and sexual orientation. E.g.,
         
         

Internet History

• See Hobbes' Internet Timeline for historical perspective.
  • Local mirror
  • Internet Growth section
  • Spanish version (not as current as the English version)

Bibliography

1. Steve Lawrence, C. Lee Giles. "Accessibility of Information on the Web." Nature, v400: July 8, 1999 (http://www.nature.com). Results online at http://www.wwwmetrics.com and analyzed in a NY Times article.
2. RelevantKnowledge, May 1999 survey.
3. Graphic, Visualization, & Usability Center (Georgia Tech), October 10 through December 15, 1998 survey.
4. Hobbes' Internet Timeline
5. Jube Shiver, Jr. "Internet Gender Gap Closes in U.S., Study Says." L.A. Times, May 11, 2000.