Architectural Principles of the Internet
RFC 1958

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Network Working Group                               B. Carpenter, Editor
Request for Comments: 1958                                           IAB
Category: Informational                                        June 1996

                Architectural Principles of the Internet

Status of This Memo

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

Abstract

   The Internet and its architecture have grown in evolutionary fashion
   from modest beginnings, rather than from a Grand Plan. While this
   process of evolution is one of the main reasons for the technology's
   success, it nevertheless seems useful to record a snapshot of the
   current principles of the Internet architecture. This is intended for
   general guidance and general interest, and is in no way intended to
   be a formal or invariant reference model.

Table of Contents

      1. Constant Change..............................................1
      2. Is there an Internet Architecture?...........................2
      3. General Design Issues........................................4
      4. Name and address issues......................................5
      5. External Issues..............................................6
      6. Related to Confidentiality and Authentication................6
      Acknowledgements................................................7
      References......................................................7
      Security Considerations.........................................8
      Editor's Address................................................8

1. Constant Change

   In searching for Internet architectural principles, we must remember
   that technical change is continuous in the information technology
   industry. The Internet reflects this.  Over the 25 years since the
   ARPANET started, various measures of the size of the Internet have
   increased by factors between 1000 (backbone speed) and 1000000
   (number of hosts). In this environment, some architectural principles
   inevitably change.  Principles that seemed inviolable a few years ago
   are deprecated today. Principles that seem sacred today will be
   deprecated tomorrow. The principle of constant change is perhaps the
   only principle of the Internet that should survive indefinitely.

IAB                          Informational                      [Page 1]
RFC 1958        Architectural Principles of the Internet       June 1996

   The purpose of this document is not, therefore, to lay down dogma
   about how Internet protocols should be designed, or even about how
   they should fit together. Rather, it is to convey various guidelines
   that have been found useful in the past, and that may be useful to
   those designing new protocols or evaluating such designs.

   A good analogy for the development of the Internet is that of
   constantly renewing the individual streets and buildings of a city,
   rather than razing the city and rebuilding it. The architectural
   principles therefore aim to provide a framework for creating
   cooperation and standards, as a small "spanning set" of rules that
   generates a large, varied and evolving space of technology.

   Some current technical triggers for change include the limits to the
   scaling of IPv4, the fact that gigabit/second networks and multimedia
   present fundamentally new challenges, and the need for quality of
   service and security guarantees in the commercial Internet.

   As Lord Kelvin stated in 1895, "Heavier-than-air flying machines are
   impossible." We would be foolish to imagine that the principles
   listed below are more than a snapshot of our current understanding.

2. Is there an Internet Architecture?

   2.1 Many members of the Internet community would argue that there is
   no architecture, but only a tradition, which was not written down for
   the first 25 years (or at least not by the IAB).  However, in very
   general terms, the community believes that the goal is connectivity,
   the tool is the Internet Protocol, and the intelligence is end to end
   rather than hidden in the network.

   The current exponential growth of the network seems to show that
   connectivity is its own reward, and is more valuable than any
   individual application such as mail or the World-Wide Web.  This
   connectivity requires technical cooperation between service
   providers, and flourishes in the increasingly liberal and competitive
   commercial telecommunications environment.

   The key to global connectivity is the inter-networking layer.  The
   key to exploiting this layer over diverse hardware providing global
   connectivity is the "end to end argument".

   2.2 It is generally felt that in an ideal situation there should be
   one, and only one, protocol at the Internet level.  This allows for
   uniform and relatively seamless operations in a competitive, multi-