rfc1935.txt

RFC 的详细文档！

   This is true, and has been done.  However, people seem to forget to
   ask why these services developed on top of IP in the first place.
   There seems to be something about IP and the Internet that is
   especially conducive to the development of new protocols.  We make no
   apologies about naming IP, because we think it is important.

   There is also the question of IP to where?  If you have a UNIX shell
   login account on a computer run by an Internet access provider, and
   that system has IP access to the rest of the Internet, then you are
   an Internet user.  However, you will not be able to use the full
   graphical capabilities of protocols such as WWW, because the
   provider's system cannot display on a bitmapped screen for you.  For
   that, you need IP to your own computer with a bitmapped screen.
   These are two different degrees of Internet connectivity that are
   important to both end users and marketers.  Some people refer to them
   as text-only interactive access and graphical interactive access.
   Some people have gone so far as to say you have to have graphical
   capabilities to have a full service Internet connection.  That may or
   may not be so, but in the interests of keeping the major categories
   to a minimum, we are simply going to note these degrees and say no
   more about them in this article.  However, we agree that the
   distinction of graphical access is becoming more important with the
   spread of WWW and Mosaic.

Conferencing Systems and Commercial Mail Systems

   Conferencing systems such as Prodigy and CompuServe that support mail
   and often something like news, plus database and services.  But most
   of them do not support the characteristic interactive services that
   we have listed.  The few that do (Delphi and AOL), we simply count as
   part of the Internet.  The others, we count as part of the Matrix,
   since they all exchange mail.



Quarterman & Carl-Mitchell   Informational                      [Page 8]

RFC 1935             What is the Internet, Anyway?            April 1996


   We find that users of conferencing systems have no particular
   difficulty in distinguishing between the conferencing system they use
   and the Internet.  CompuServe users, for example, refer to "Internet
   mail", which is correct, since the only off-system mail CompuServe
   supports is to the Internet, but they do not in general refer to
   CompuServe as part of the Internet.

   Similarly, users of the various commercial electronic mail networks,
   such as MCI Mail and Sprint-Mail, seem to have no difficulty in
   distinguishing between the mail network they use and the Internet.
   Since they all seem to have their own addressing syntax, this is
   hardly surprising.  We count these commercial mail networks as part
   of the Matrix, but not part of the Internet.  Many of them have IP
   links to the Internet, but they don't let their users use them,
   instead limiting the services they carry to just mail.

Russian Dolls

   So let's think of a series of nested Chinese boxes or Russian dolls;
   the kind where inside Boris Yeltsin is Mikhail Gorbachov, inside
   Gorbachov is Brezhnev, then Kruschev, Stalin, Lenin, and maybe even
   Tsar Nicholas II.  Let's not talk about that many concentric layers,
   though, rather just three: the Matrix on the outside, the consumer
   Internet inside, and the core Internet inside that.

                    the core        the consumer    the Matrix
                    Internet        Internet

    interactive     supplier-       consumer-       by mail
    services        capable         capable

                    stores and      shoppers        mail
                    shoppers                        order

    asynchronous    yes             yes             yes services

   Some people have argued that these categories are bad because they
   are not mutually exclusive.  Well, we observe that in real life
   networks have differing degrees of services, and the ones of most
   interest share the least common denominator of electronic mail.  Thus
   concentric categories are needed to describe the real world.  You
   can, however, extract three mutually-exclusive categories by
   referring to the core Internet, the interactive consumer-only part of
   the Internet, and to asynchronous systems.

   Other people have argued that these categories are not sequential.
   They look sequential to us, since if you start with the core Internet
   and move out, you subtract services, and if you start at the outside



Quarterman & Carl-Mitchell   Informational                      [Page 9]

RFC 1935             What is the Internet, Anyway?            April 1996


   of the Matrix and move in, you add services.

Outside the Matrix

   In addition to computers and networks that fit these classifications,
   there are also LANs, mainframes, and BBSes that don't exchange any
   services with other networks or computers; not even mail.  These
   systems are outside the Matrix.  For example, many companies have an
   AppleTalk LAN in marketing, a Novell NetWare LAN in management, and a
   mainframe in accounting that aren't connected to talk to anything
   else.  In addition, there are a few large networks such as France's
   Teletel (commonly known as Minitel) that support very large user
   populations but don't communicate with anything else.  These are all
   currently outside all our Chinese boxes of the core Internet, the
   consumer Internet, and the Matrix.

DNS and Mail Addresses

   There are other interesting network services that make a difference
   to end users.  For example, DNS (Domain Name System) domain names
   such as tic.com and domain addresses such [e-mail] can be set up
   for systems outside the Internet.  We used tic.com when we only had a
   UUCP connection, and few of our correspondents noticed any difference
   when we added an IP connection (except our mail was faster).  This
   would be more or less a box enclosing the consumer Internet and
   within the Matrix.  But the other three boxes are arguably the most
   important.

   Some people have claimed that anything that uses DNS addresses is
   part of the Internet.  We note that DNS addresses can be used with
   the UUCP network, which supports no interactive services, and we
   reject such an equation.

   It is interesting to note that over the years various attempts have
   been made to equate the Internet with something else.  Until the
   mid-1980s lots of people tried to say the Internet was the ARPANET.
   In the late 1980s many tried to say the Internet was NSFNET.  In the
   early 1990s many tried to say the Internet was USENET.  Now many are
   trying to say the Internet is anything that can exchange mail.  We
   say the Internet is the Internet, not the same as anything else.

Summary

   So, here we have a simple set of categories for several of the
   categories of network access people talk about most these days.  Any
   such categories are at least somewhat a matter of opinion, and other
   people will propose other categories and other names.  We like these
   categories, because they fit our experience of what real users



Quarterman & Carl-Mitchell   Informational                     [Page 10]

RFC 1935             What is the Internet, Anyway?            April 1996


   actually perceive.

   You'll notice we've avoided use of the words "connected" and
   "reachable" because they mean different things to different people at
   different times.  For either of them to be meaningful, you have to
   say which services you are talking about.  To us, reachable usually
   means pingable with ICMP ECHO, which is another way to define the
   core Internet.  To others, reachable might mean you can send mail
   there, which is another way to define the Matrix.

   Once we have terms for networks of interest, we can talk about how
   big those networks are.  We think the terms we have defined here
   refer to groups of computers that people want to use, and that some
   people want to measure.  Many marketers want to know about users.
   Well, users of mail are in the Matrix, and users of interactive
   services such as WWW and FTP are in the Internet.  Other people are
   more interested in suppliers or distributors of information.
   Suppliers of information by mail can be anywhere in the Matrix, but
   suppliers of information by WWW or FTP are in the core Internet.  It
   is easy to define more and finer degrees of distinctions of
   capabilities and connectivity, but these three major categories
   handle the most important cases.

   We invite our readers to tell us what distinctions they find
   important about the various networks and their services.

Security Considerations

   Security issues are not discussed in this memo.

Authors' Addresses

   John S. Quarterman
   Smoot Carl-Mitchell

   EMail: [e-mail]















Quarterman & Carl-Mitchell   Informational                     [Page 11]