Status of CIDR Deployment in the Internet
RFC 1467

Document Type RFC - Historic (August 1993; No errata)
Obsoletes RFC 1367
Last updated 2013-03-02
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Network Working Group                                        C. Topolcic
Request for Comments: 1467                                          CNRI
Obsoletes: 1367                                              August 1993

               Status of CIDR Deployment in 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


   This document describes the current status of the development and
   deployment of CIDR technology into the Internet. This document
   replaces RFC 1367, which was a schedule for the deployment of IP
   address space management procedures to support route aggregation.
   Since all the milestones proposed in RFC 1367 except for the delivery
   and installation of CIDR software were met, it does not seem
   appropriate to issue an updated schedule. Rather, this document is
   intended to provide information about how this effort is proceeding,
   which may be of interest to the community.

1. Background

   The Internet's exponential growth has led to a number of difficulties
   relating to the management of IP network numbers.  The administrative
   overhead of allocating ever increasing volumes of IP network numbers
   for global users has stressed the organizations that perform this
   function.  The volume of IP network numbers that are reachable
   through the Internet has taxed a number of routers' ability to manage
   their forwarding tables.  The poor utilization of allocated IP
   network numbers has threatened to deplete the Class A and Class B
   address space.

   During the past few years, a consensus has emerged among the Internet
   community in favor of a number of mechanisms to relieve these
   problems for the mid-term.  These mechanisms are expected to be put
   into place in the short term and to provide relief for the mid-term.
   Fundamental changes to the Internet protocols to ensure the
   Internet's continued long term growth and well being are being
   explored and are expected to succeed the mid-term mechanisms.

   The global Internet community have been cooperating closely in such
   forums as the IETF and its working groups, the IEPG, the NSF Regional
   Techs Meetings, INET, INTEROP, FNC, FEPG, and other assemblies in

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RFC 1467       Status of CIDR Deployment in the Internet     August 1993

   order to ensure the continued stable operation of the Internet.
   Recognizing the need for the mid-term mechanisms and receiving
   support from the Internet community, the US Federal Agencies proposed
   procedures to assist the deployment of these mid-term mechanisms.
   These procedures were originally described in RFC 1366 [1], which was
   recently made obsolete by RFC 1466 [2].  In October 1992, a schedule
   was proposed for the implementation of the procedures, described in
   RFC 1367 [3].

2. Milestones that have been met

   Most of the milestones of the proposed schedule were implemented on
   time. These milestones are shown below, essentially as they appear in
   [3], but with further comment where appropriate:

      1) 31 October 92:

         The following address allocation procedures were continued:

         a) Initial set of criteria for selecting regional address
            registries were put into place, and requests from
            prospective regional registries were accepted by the

            The Reseaux IP Europeens Network Coordination Centre
            (RIPE NCC) requested to become a regional registry.
            As per the addressing plan of RFC 1366, the RIPE NCC
            was given the block to to
            administer for the European Internet community. The RIPE
            NCC had previously and independently obtained the block
   to Although this block had been
            allocated before RFC 1366, the RIPE NCC was able to manage
            it according to the guidelines in RFC 1366.

         b) Class A network numbers were put on reserve for possible
            future use. The unreserved Class A numbers became very
            difficult to obtain.

         c) Class B network numbers were issued only when
            reasonably justified.  Whenever possible, a block of C's
            was issued rather than a B. The requirements for
            allocating a Class B became progressively more constrained
            until the date in step (3).

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RFC 1467       Status of CIDR Deployment in the Internet     August 1993

         d) Class C network numbers were allocated according to the
            addressing plan of [1], now obsoleted by [2].  Allocation
            continued to be performed by the Internet Registry (IR)
            for regions of the world where an appropriate regional
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