rfc1462.txt

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Network Working Group                                          E. Krol
Request for Comments: 1462                      University of Illinois
FYI: 20                                                     E. Hoffman
                                                   Merit Network, Inc.
                                                              May 1993


                     FYI on "What is the Internet?"

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard.  Distribution of this memo is
   unlimited.

Abstract

   This FYI RFC answers the question, "What is the Internet?" and is
   produced by the User Services Working Group of the Internet
   Engineering Task Force (IETF). Containing a modified chapter from Ed
   Krol's 1992 book, "The Whole Internet User's Guide and Catalog," the
   paper covers the Internet's definition, history, administration,
   protocols, financing, and current issues such as growth,
   commercialization, and privatization.

Introduction

   A commonly asked question is "What is the Internet?" The reason such
   a question gets asked so often is because there's no agreed upon
   answer that neatly sums up the Internet. The Internet can be thought
   about in relation to its common protocols, as a physical collection
   of routers and circuits, as a set of shared resources, or even as an
   attitude about interconnecting and intercommunication. Some common
   definitions given in the past include:

      * a network of networks based on the TCP/IP protocols,
      * a community of people who use and develop those networks,
      * a collection of resources that can be reached from those
        networks.

   Today's Internet is a global resource connecting millions of users
   that began as an experiment over 20 years ago by the U.S.  Department
   of Defense. While the networks that make up the Internet are based on
   a standard set of protocols (a mutually agreed upon method of
   communication between parties), the Internet also has gateways to
   networks and services that are based on other protocols.





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   To help answer the question more completely, the rest of this paper
   contains an updated second chapter from "The Whole Internet User's
   Guide and Catalog" by Ed Krol (1992) that gives a more thorough
   explanation. (The excerpt is published through the gracious
   permission of the publisher, O'Reilly & Associates, Inc.)

The Internet (excerpt from "The Whole Internet User's Guide and
Catalog")

   The Internet was born about 20 years ago, trying to connect together
   a U.S. Defense Department network called the ARPAnet and various
   other radio and satellite networks. The ARPAnet was an experimental
   network designed to support military research--in particular,
   research about how to build networks that could withstand partial
   outages (like bomb attacks) and still function.  (Think about this
   when I describe how the network works; it may give you some insight
   into the design of the Internet.) In the ARPAnet model, communication
   always occurs between a source and a destination computer. The
   network itself is assumed to be unreliable; any portion of the
   network could disappear at any moment (pick your favorite
   catastrophe--these days backhoes cutting cables are more of a threat
   than bombs). It was designed to require the minimum of information
   from the computer clients. To send a message on the network, a
   computer only had to put its data in an envelope, called an Internet
   Protocol (IP) packet, and "address" the packets correctly. The
   communicating computers--not the network itself--were also given the
   responsibility to ensure that the communication was accomplished. The
   philosophy was that every computer on the network could talk, as a
   peer, with any other computer.

   These decisions may sound odd, like the assumption of an "unreliable"
   network, but history has proven that most of them were reasonably
   correct. Although the Organization for International Standardization
   (ISO) was spending years designing the ultimate standard for computer
   networking, people could not wait. Internet developers in the US, UK
   and Scandinavia, responding to market pressures, began to put their
   IP software on every conceivable type of computer. It became the only
   practical method for computers from different manufacturers to
   communicate. This was attractive to the government and universities,
   which didn't have policies saying that all computers must be bought
   from the same vendor. Everyone bought whichever computer they liked,
   and expected the computers to work together over the network.

   At about the same time as the Internet was coming into being,
   Ethernet local area networks ("LANs") were developed. This technology
   matured quietly, until desktop workstations became available around
   1983. Most of these workstations came with Berkeley UNIX, which
   included IP networking software. This created a new demand: rather



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   than connecting to a single large timesharing computer per site,
   organizations wanted to connect the ARPAnet to their entire local
   network. This would allow all the computers on that LAN to access
   ARPAnet facilities. About the same time, other organizations started
   building their own networks using the same communications protocols
   as the ARPAnet: namely, IP and its relatives. It became obvious that
   if these networks could talk together, users on one network could
   communicate with those on another; everyone would benefit.

   One of the most important of these newer networks was the NSFNET,
   commissioned by the National Science Foundation (NSF), an agency of
   the U.S. government. In the late 80's the NSF created five
   supercomputer centers. Up to this point, the world's fastest
   computers had only been available to weapons developers and a few
   researchers from very large corporations. By creating supercomputer
   centers, the NSF was making these resources available for any
   scholarly research. Only five centers were created because they were
   so expensive--so they had to be shared. This created a communications
   problem: they needed a way to connect their centers together and to
   allow the clients of these centers to access them.  At first, the NSF
   tried to use the ARPAnet for communications, but this strategy failed
   because of bureaucracy and staffing problems.

   In response, NSF decided to build its own network, based on the
   ARPAnet's IP technology. It connected the centers with 56,000 bit per
   second (56k bps) telephone lines.  (This is roughly the ability to
   transfer two full typewritten pages per second.  That's slow by
   modern standards, but was reasonably fast in the mid 80's.)  It was
   obvious, however, that if they tried to connect every university
   directly to a supercomputing center, they would go broke. You pay for
   these telephone lines by the mile. One line per campus with a
   supercomputing center at the hub, like spokes on a bike wheel, adds
   up to lots of miles of phone lines. Therefore, they decided to create
   regional networks. In each area of the country, schools would be
   connected to their nearest neighbor. Each chain was connected to a
   supercomputer center at one point and the centers were connected
   together. With this configuration, any computer could eventually
   communicate with any other by forwarding the conversation through its
   neighbors.

   This solution was successful--and, like any successful solution, a
   time came when it no longer worked. Sharing supercomputers also
   allowed the connected sites to share a lot of other things not
   related to the centers. Suddenly these schools had a world of data
   and collaborators at their fingertips. The network's traffic
   increased until, eventually, the computers controlling the network
   and the telephone lines connecting them were overloaded. In 1987, a
   contract to manage and upgrade the network was awarded to Merit



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   Network Inc., which ran Michigan's educational network, in
   partnership with IBM and MCI. The old network was replaced with
   faster telephone lines (by a factor of 20), with faster computers to
   control it.

   The process of running out of horsepower and getting bigger engines
   and better roads continues to this day. Unlike changes to the highway
   system, however, most of these changes aren't noticed by the people
   trying to use the Internet to do real work. You won't go to your
   office, log in to your computer, and find a message saying that the
   Internet will be inaccessible for the next six months because of
   improvements. Perhaps even more important: the process of running out
   of capacity and improving the network has created a technology that's
   extremely mature and practical. The ideas have been tested; problems
   have appeared, and problems have been solved.

   For our purposes, the most important aspect of the NSF's networking
   effort is that it allowed everyone to access the network. Up to that
   point, Internet access had been available only to researchers in
   computer science, government employees, and government contractors.
   The NSF promoted universal educational access by funding campus
   connections only if the campus had a plan to spread the access
   around. So everyone attending a four year college could become an
   Internet user.

   The demand keeps growing. Now that most four-year colleges are
   connected, people are trying to get secondary and primary schools
   connected. People who have graduated from college know what the
   Internet is good for, and talk their employers into connecting
   corporations. All this activity points to continued growth,
   networking problems to solve, evolving technologies, and job security
   for networkers.

What Makes Up the Internet?

   What comprises the Internet is a difficult question; the answer
   changes over time. Five years ago the answer would have been easy:
   "All the networks, using the IP protocol, which cooperate to form a
   seamless network for their collective users." This would include
   various federal networks, a set of regional networks, campus
   networks, and some foreign networks.

   More recently, some non-IP-based networks saw that the Internet was
   good. They wanted to provide its services to their clientele. So they
   developed methods of connecting these "strange" networks (e.g.,
   Bitnet, DECnets, etc.) to the Internet. At first these connections,
   called "gateways", merely served to transfer electronic mail between
   the two networks. Some, however, have grown to translate other



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   services between the networks as well. Are they part of the Internet?
   Maybe yes and maybe no. It depends on whether, in their hearts, they
   want to be. If this sounds strange, read on--it gets stranger.

Who Governs the Internet?

   In many ways the Internet is like a church: it has its council of
   elders, every member has an opinion about how things should work, and
   you can either take part or not. It's your choice. The Internet has
   no president, chief operating officer, or Pope. The constituent
   networks may have presidents and CEO's, but that's a different issue;
   there's no single authority figure for the Internet as a whole.

   The ultimate authority for where the Internet is going rests with the
   Internet Society, or ISOC. ISOC is a voluntary membership
   organization whose purpose is to promote global information exchange
   through Internet technology.  (If you'd like more information, or if
   you would like to join, contact information is provided in the "For
   More Information" section, near the end of this document.)  It
   appoints a council of elders, which has responsibility for the
   technical management and direction of the Internet.

   The council of elders is a group of invited volunteers called the
   Internet Architecture Board, or the IAB. The IAB meets regularly to
   "bless" standards and allocate resources, like addresses. The
   Internet works because there are standard ways for computers and
   software applications to talk to each other. This allows computers
   from different vendors to communicate without problems. It's not an
   IBM-only or Sun-only or Macintosh-only network. The IAB is
   responsible for these standards; it decides when a standard is
   necessary, and what the standard should be. When a standard is
   required, it considers the problem, adopts a standard, and announces
   it via the network. (You were expecting stone tablets?) The IAB also
   keeps track of various numbers (and other things) that must remain
   unique. For example, each computer on the Internet has a unique 32-
   bit address; no other computer has the same address.  How does this
   address get assigned? The IAB worries about these kinds of problems.
   It doesn't actually assign the addresses, but it makes the rules
   about how to assign addresses.

   As in a church, everyone has opinions about how things ought to run.
   Internet users express their opinions through meetings of the
   Internet Engineering Task Force (IETF). The IETF is another volunteer
   organization; it meets regularly to discuss operational and near-term
   technical problems of the Internet. When it considers a problem
   important enough to merit concern, the IETF sets up a "working group"
   for further investigation. (In practice, "important enough" usually
   means that there are enough people to volunteer for the working



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   group.) Anyone can attend IETF meetings and be on working groups; the
   important thing is that they work. Working groups have many different
   functions, ranging from producing documentation, to deciding how
   networks should cooperate when problems occur, to changing the
   meaning of the bits in some kind of packet. A working group usually
   produces a report. Depending on the kind of recommendation, it could
   just be documentation and made available to anyone wanting it, it
   could be accepted voluntarily as a good idea which people follow, or
   it could be sent to the IAB to be declared a standard.

   If you go to a church and accept its teachings and philosophy, you
   are accepted by it, and receive the benefits. If you don't like it,
   you can leave. The church is still there, and you get none of the
   benefits. Such is the Internet. If a network accepts the teachings of
   the Internet, is connected to it, and considers itself part of it,
   then it is part of the Internet. It will find things it doesn't like
   and can address those concerns through the IETF. Some concerns may be
   considered valid and the Internet may change accordingly.  Some of
   the changes may run counter to the religion, and be rejected. If the
   network does something that causes damage to the Internet, it could
   be excommunicated until it mends its evil ways.

Who Pays for It?