RFC 1627 (rfc1627) - Page 1 of 8

Network 10 Considered Harmful (Some Practices Shouldn't be Codified)

Network Working Group                                            E. Lear
Request for Comments: 1627                        Silicon Graphics, Inc.
Category: Informational                                          E. Fair
                                                    Apple Computer, Inc.
                                                              D. Crocker
                                                  Silicon Graphics, Inc.
                                                              T. Kessler
                                                  Sun Microsystems, Inc.
                                                               July 1994


                     Network 10 Considered Harmful
                 (Some Practices Shouldn't be Codified)

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.

SUMMARY

   Re-use of Internet addresses for private IP networks is the topic of
   the recent RFC 1597 [1].  It reserves a set of IP network numbers,
   for (re-)use by any number of organizations, so long as those
   networks are not routed outside any single, private IP network.  RFC
   1597 departs from the basic architectural rule that IP addresses must
   be globally unique, and it does so without having had the benefit of
   the usual, public review and approval by the IETF or IAB.  This
   document restates the arguments for maintaining a unique address
   space.  Concerns for Internet architecture and operations, as well as
   IETF procedure, are explored.

INTRODUCTION

   Growth in use of Internet technology and in attachments to the
   Internet have taken us to the point that we now are in danger of
   running out of unassigned IP network numbers.  Initially, numbers
   were formally assigned only when a network was about to be attached
   to the Internet.  This caused difficulties when initial use of IP
   substantially preceded the decision and permission to attach to the
   Internet.  In particular, re-numbering was painful.  The lesson that
   we learned was that every IP address ought to be globally unique,
   independent of its attachment to the Internet.  This makes it
   possible for any two network entities to communicate, no matter where
   either might be located.  This model is the result of a decades-long
   evolution, through which the community realized how painful it can be
   to convert a network of computers to use an assigned number after



Lear, Fair, Crocker & Kessler