Hitchhikers Guide to the Internet | Page 3

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****** The Hitchhikers Guide to the Internet 25 August 1987

Ed Krol [email protected]

This document was produced through funding of the National Science
Foundation.
Copyright (C) 1987, by the Board of Trustees of The University of
Illinois. Permission to duplicate this document, in whole or part, is
granted provided reference is made to the source and this copyright is
included in whole copies.
This document assumes that one is familiar with the workings of a
non-connected simple IP network (e.g. a few 4.2 BSD systems on an
Ethernet not connected to anywhere else). Appendix A contains
remedial information to get one to this point. Its purpose is to get that
person, familiar with a simple net, versed in the "oral tradition" of the
Internet to the point that that net can be connected to the Internet with
little danger to either. It is not a tutorial, it consists of pointers to other
places, literature, and hints which are not normally documented. Since
the Internet is a dynamic environment, changes to this document will
be made regularly. The author welcomes comments and suggestions.
This is especially true of terms for the glossary (definitions are not
necessary).

In the beginning there was the ARPAnet, a wide area experimental
network connecting hosts and terminal servers together. Procedures
were set up to regulate the allocation of addresses and to create
voluntary standards for the network. As local area networks became
more pervasive, many hosts became gateways to local networks. A
network layer to allow the interoperation of these networks was
developed and called IP (Internet Protocol). Over time other groups

created long haul IP based networks (NASA, NSF, states...). These nets,
too, interoperate because of IP. The collection of all of these
interoperating networks is the Internet.
Two groups do much of the research and information work of the
Internet (ISI and SRI). ISI (the Informational Sciences Institute) does
much of the research, standardization, and allocation work of the
Internet. SRI International provides information services for the
Internet. In fact, after you are connected to the Internet most of the
information in this document can be retrieved from the Network
Information Center (NIC) run by SRI.

Operating the Internet
Each network, be it the ARPAnet, NSFnet or a regional network, has
its own operations center. The ARPAnet is run by BBN, Inc. under
contract from DARPA. Their facility is called the Network Operations
Center or NOC. Cornell University temporarily operates NSFnet
(called the Network Information Service Center, NISC). It goes on to
the
-2-
regionals having similar facilities to monitor and keep watch over the
goings on of their portion of the Internet. In addition, they all should
have some knowledge of what is happening to the Internet in total. If a
problem comes up, it is suggested that a campus network liaison should
contact the network operator to which he is directly connected. That is,
if you are connected to a regional network (which is gatewayed to the
NSFnet, which is connected to the ARPAnet...) and have a problem,
you should contact your regional network operations center.
RFCs
The internal workings of the Internet are defined by a set of documents
called RFCs (Request for Comments). The general process for creating
an RFC is for someone wanting something formalized to write a
document describing the issue and mailing it to Jon Postel
([email protected]). He acts as a referee for the proposal. It is then
commented upon by all those wishing to take part in the discussion
(electronically of course). It may go through multiple revisions. Should
it be generally accepted as a good idea, it will be assigned a number
and filed with the RFCs.

The RFCs can be divided into five groups: required, suggested,
directional, informational and obsolete. Required RFC's (e.g. RFC-791,
The Internet Protocol) must be implemented on any host connected to
the Internet. Suggested RFCs are generally implemented by network
hosts. Lack of them does not preclude access to the Internet, but may
impact its usability. RFC-793 (Transmission Control Protocol) is a
suggested RFC. Directional RFCs were discussed and agreed to, but
their application has never come into wide use. This may be due to the
lack of wide need for the specific application (RFC-937 The Post
Office Protocol) or that, although technically superior, ran against other
pervasive approaches (RFC-891 Hello). It is suggested that should the
facility be required by a particular site, animplementation be done in
accordance with the RFC. This insures that, should the idea be one
whose time has come, the implementation will be in accordance with
some standard and will be generally usable. Informational RFCs
contain factual information about the Internet and its operation