Introduction 101

In this tutorial you should learn:

  • The definition of the Internet and related technologies.
  • The hierarchical structure of the Internet.
  • The origins of the Internet, its growth and its current status.
  • Applications based on the Internet: TELNET, FTP, and e-mail.
  • The notions of restricted Internet networks: Intranets and Extranets.


Definition of The Internet

(the Net, the information superhighway, cyberspace, the Infobahn)

According to the unanimously passed Resolution of The Federal Networking Council (FNC) of October 24, 1995 the Internet was defined as the following:

RESOLUTION: agrees that the following language reflects our definition of the term "Internet". "Internet" refers to the global information system that -- (i) is logically linked together by a globally unique address space based on the Internet Protocol (IP) or its subsequent extensions/follow-ons; (ii) is able to support communications using the Transmission Control Protocol/Internet Protocol (TCP/IP) suite or its subsequent extensions/follow-ons, and/or other IP-compatible protocols; and (iii) provides, uses or makes accessible, either publicly or privately, high level services layered on the communications and related infrastructure described herein.

" (i) is logically linked together by a globally unique address space based on the Internet Protocol (IP)"

  • Protocol is a set of rules, or standards that determine the ways a network operates.
  • The IP - Internet Protocol is the address system based on four eight bits numbers (e.g. 128.153.4.2 is a primary address for CU). An alternative form DNS - Domain Name Service was developed to make it easier for the users to remember addresses (e.g., http://www.clarkson.edu). DNS server performs DNS-lookup to translate a domain name into IP address.
  • If you want to find your Internet Host Address, you may select: Start, Run; enter command into the window and click OK. At the DOS prompt, enter ipconfig and hit enter. Below is the result for my personal computer connected to the Northnet ASP via modem (PPP - Point-to-Point Protocol, governs TCP/IP transmission over serial, e.g., modem, connections):

(ii) is able to support communications using the Transmission Control Protocol/Internet Protocol (TCP/IP) suite

  • TCP/IP protocol suite is a set of protocols used on the Internet: TCP, IP, SLIP, and PPP.
  • TCP - Transmission Control Protocol handles breaking information into indipendent packets, or datagrams, each having its own size and sequence number stamped on it and passing them to IP for transmission over the network. It also responsible for marshalling and sorting received packets, and basic packet error detection. IP creates the "envelopes" with source and destination addresses to carry each datagram of information via routers to its destination.
  • The router is a computer, connected to the Internet, which contains information about the internal map of the Internet. The router reads the data packet, identifies which computer a datagram is being sent to, and sends it down the shortest or fastest route to its destination.
  • SLIP - Serial Line Internet Protocol is a standard for using a regular telephone line (a "serial line") and a modem to connect a computer as a real Internet site.
  • PPP - Point-to-Point Protocol is a standard that allows computers to operate over a dial-up connection.

(iii) provides, uses or makes accessible, either publicly or privately, high level services layered on the communications and related infrastructure described herein.

The Internet is a global network of networks enabling computers of all kinds to directly and transparently communicate and share services throughout much of the world. It has the following hierarchical structure.

  • Level 1: Interconnect level -- National Access Points (NAPs): New York, Chicago, San Francisco and Washington, DC.
  • Level 2: National Backbone -- High speed (>2,000 Mbps) communication lines, leased from long distance telephone companies, connected by high-speed computers-routers. Providers are MCI Internet, Sprint, BBN Planet and other companies.
  • Level 3: Regional Internet providers, e.g., The Internet Access Company, Boston, MA
  • Level 4: Local Internet Service Providers (ISPs), e.g. Norhtnet, Nicholville
  • Level 5: Local Networks, Businesses and Consumers (can access the Internet via providers at any level)

 

Minimalist History of the Internet

The starting point

  • 1957: USSR launches Sputnik, first artificial earth satellite. In response, US forms the Advanced Research Projects Agency (ARPA) within the Department of Defense (DoD) to establish US lead in science and technology applicable to the military purposes.
  • 1969: ARPAnet (4 computers) is in operation.
  • Around Labor Day in 1969, BBN delivered an Interface Message Processor (IMP) to UCLA that was based on a Honeywell DDP 516, and when they turned it on, it just started running. It was hooked by 50 Kbps circuits to two other sites (SRI and UCSB) in the four-node network: UCLA, Stanford Research Institute (SRI), UC Santa Barbara (UCSB), and the University of Utah in Salt Lake City.

    "We set up a telephone connection between us and the guys at SRI...," Kleinrock ... said in an interview: "We typed the L and we asked on the phone,

    "Do you see the L?"
    "Yes, we see the L," came the response.
    "We typed the O, and we asked, "Do you see the O."
    "Yes, we see the O."
    "Then we typed the G, and the system crashed"...

    Yet a revolution had begun"...

    Source: Sacramento Bee, May 1, 1996, p.D1

Growth over time

http://info.isoc.org/guest/zakon/Internet/History/HIT.html#Growth

  • Networks = registered network addresses
  • Hosts = a computer system with registered IP address
  • Domains = registered domain name (with name server record)
  • According to the release of American Internet Society of Septermber 2000, 171 million users were connected to the Internet in 1999, this number grew up to 304 million in 2000 and expected to reach 1 billion by 2005.

The turning point in the Internet growth (May-October 1995)

  • There are two ages of the Internet - before Mosaic, and after. The combination of Tim Berners-Lee's Web protocols, which provided connectivity, and Marc Andreesen's browser, which provided a great interface, proved explosive. In twenty-four months, the Web has gone from being unknown to absolutely ubiquitous.

    A Brief History of Cyberspace, by Mark Pesce, ZDNet, October 15, 1995

  • 1995: Technologies of the Year: WWW, Search engines became prominent.

 

Prominent Applications based on the TCP/IP.

Application Protocols: TELNET, FTP, and SMTP

  • TELNET is an application protocol within TCP/IP. It enables terminal emulation, so a user PC can directly connect to a host computer as a terminal. It requires Login ID and Password.
  • File Transfer Protocol (FTP) is an algorithm that enables the transfer of files of data from one remote device to another, using TCP and TELNET protocols.
  • Simple Mail Transfer Protocol (SMTP) is a handy alternative to FTP for sending files over the network that does not require Login ID and Password. It needs only a e-mail address for the receiving end.

Restricted Networks Based on TCP/IP

  • Intranet is an internal, or private network of computers that talks via TCP/IP protocols and used for sharing data within the organization
  • Extranet (Sharing Nets)is two or more intranets connected using TCP/IP protocols.
  • See http://phoenix.som.clarkson.edu/pants/projects.htm for more on Intranets and Extranets


We have learned:

  • The definition of the Internet as a global network of networks communicating via TCP/IP suite of protocols.
  • Basic characteristics of TCP, IP, and DNS protocols.
  • The hierarchical five-level structure of the Internet consisting of National Access Points (NAPs), National Backbone, Regional, Local Providers (ISPs), and Customers (Local Networks, Businesses and individuals).
  • Some applications based on TCP/IP: TELNET, FTP, and e-mail ( SMTP) and the basic characteristics of these protocols.
  • That the Internet had a humble start as ARPANET with only four computers, that currently it is a global network of hundred of thousands of networks and millions of hosts and sites, and still is growing exponentially.
  • That this growth is due to development of WWW, search engines, and browsers MOSAIC, Netscape Communicator, MS Internet Explorer.
  • The notions of restricted private Internet networks, Intranets and Extranets.

For more information on the Internet and the Web and their history see: