Allocation of IP Addresses

Jim Fleming JimFleming at
Thu Mar 14 07:17:36 UTC 1996

From: 	David R. Conrad[SMTP:davidc at]
Sent: 	Wednesday, March 13, 1996 10:30 PM
To: 	Jim Browning
Cc: 	'David R. Conrad'; Michael Dillon; 'com-priv list'; davidc at; 'NANOG List'; 'NIC Registry list'
Subject: 	Re: Allocation of IP Addresses 


>The answer is to have published, objective criteria, consistently applied, 
>with a defined appeal process and accountability.  

See the latest allocation policy draft -- it attempts to do that.
Comments on the draft would be welcome, see:


>It's hard to play by the 
>rules if you don't know what they are, and one has only to look at the /14 
>allocation to @Home to realize that the "slow start" rules do not apply to 
>everyone equally.

The @Home allocation was done outside of normal registry procedures by
the IANA directly.  InterNIC should not be held responsible for that


In case people do not know where to look....

or for those that do not have a web browser...see below

Jim Fleming
Naperville, IL


INTERNET-DRAFT                                          K. Hubbard
                                                        M. Kosters
                                                        D. Conrad
                                                        D. Karrenberg
                                                        November 1995


Status of this Memo

   This document is an Internet Draft.  Internet Drafts are
   working documents of the Internet Engineering Task Force
   (IETF), its Areas, and its Working Groups.  Note that
   other groups may also distribute working documents as
   Internet Drafts.

   Internet Drafts are draft documents valid for a maximum
   of six months.  Internet Drafts may be updated, replaced,
   or obsoleted by other documents at any time.  It is not
   appropriate to use Internet Drafts as reference material
   or to cite them other than as a ``working draft'' or
   ``work in progress.''

   To learn the current status of any Internet-Draft, please check
   the ``1id-abstracts.txt'' listing contained in the Internet-
   Drafts Shadow Directories on (Africa),
   (Europe), (Pacific Rim), (US East
   Coast), or (US West Coast).


This document describes the registry system for the distribution of
globally unique Internet address space and registry operations.
Particularly this document describes the rules and guidelines
governing the distribution of this address space.

This document does not describe private Internet address space and
multicast address space.  It also does not describe regional and local
refinements of the global rules and guidelines.

This document can be considered the base set of operational guidelines
in use by all registries.  Additional guidelines may be imposed by a
particular registry as appropriate.

Expiration Date May 1996                                [Page 1]


Table of Contents

    1.  Introduction.......................................3

    2.  Allocation Framework...............................5

    2.1  Guidelines for Internet Service Providers.........5

    2.2  Submission of Reassignment Information............7

    3.   Assignment Framework..............................8

    3.1  Common Registry Requirements......................8

    3.2  Network Engineering Plans.........................9

    3.3  Previous Assignment History.......................10

    3.4  Network Deployment Plans..........................10

    3.5  Organization Information..........................11

    3.6  Expected Utilization Rate.........................11

    4.   Operational Guidelines for Registries.............11

    5.   In-Addr.Arpa Domain Maintenance...................12

    6.   Right to Appeal...................................12

    7.   References........................................13

    8.   Authors' Addresses................................13

Expiration Date May 1996                                [Page 2]



Internet address space is distributed according to the following
three goals:

1) Conservation: Fair distribution of globally unique Internet address
space according to the operational needs of the end-users and Internet
Service Providers operating networks using this address space.
Prevention of stockpiling in order to maximize the lifetime of the
Internet address space.

2) Routability: Distribution of globally unique Internet addresses
in a hierarchical manner, permitting the routing scalability of
the addresses. This scalability is necessary to ensure proper
operation of Internet routing, although it must be stressed that
routability is in no way guaranteed with the allocation or
assignment of IPv4 addresses.

3) Registration: Provision of a public registry documenting address
space allocation and assignment.  This is necessary to ensure
uniqueness and to provide information for Internet trouble shooting
at all levels.

It is in the interest of the Internet community as a whole that the
above goals be pursued.  However it should be noted that
"Conservation" and "Routability" are often conflicting goals.  All
the above goals may sometimes be in conflict with the interests of
individual end-users or Internet service providers.  Careful analysis
and judgement is necessary in each individual case to find an
appropriate compromise.

The Internet Registry system

In order to achieve the above goals the Internet Registry (IR)
hierarchy was established.

The Internet Registry hierarchy consists of the following levels
of hierarchy as seen from the top down: IANA, Regional IRs, Local IRs.


The Internet Assigned Numbers Authority has authority over all number
spaces used in the Internet.  This includes Internet Address Space.
IANA allocates parts of the Internet address space to regional IRs
according to their established needs.

Expiration Date May 1996                                [Page 3]


Regional IRs

Regional IRs operate in large geopolitical regions such as continents.
Currently there are three regional IRs established; InterNIC serving
North America, RIPE NCC serving Europe, and AP-NIC serving the Asian
Pacific region.  Since this does not cover all areas, regional IRs
also serve areas around their core service areas.  It is expected
that the number of regional IRs will remain relatively small.
Service areas will be of continental dimensions.

Regional IRs are established under the authority of the IANA.  This
requires consensus within the Internet community of the region.  A
consensus of Internet Service Providers in that region may be
necessary to fulfill that role.

The specific duties of the regional IRs include coordination and
representation of all local IRs in their respective regions.

Local IRs

Local IRs are established under the authority of the regional IR and
IANA.  These local registries have the same role and responsibility
as the regional registries within their designated geographical areas.
These areas are usually of national dimensions.

Expiration Date May 1996                                [Page 4]
INTERNET REGISTRY GUIDELINES                        November 1995

                    II.  ALLOCATION FRAMEWORK

 2.1  Guidelines for Internet Service Providers (ISPs)

This document makes a distinction between the allocation of IP
addresses and the assignment of IP addresses.  Addresses are allocated
to ISPs to assign to their customer base.

ISPs who exchange routing information with other ISPs at multiple
locations and operate without default routing may request space
directly from the regional registry in their geographical area.
ISPs with no designated regional registry may contact any regional
registry and the regional registry may either handle the request
or refer the request to an appropriate registry.

To facilitate hierarchical addressing, implemented using Classless
Inter-Domain Routing (CIDR), all other ISPs should request address
space directly from their upstream provider.  It is preferred that ISPs
only request address space directly from regional registries if their
immediate requirement, when satisfied with a contiguous block
allocation, has a reasonable probability of being routable on the
Internet, and they meet one or more of the following conditions.

       a)  the ISP is directly connected to a major routing exchange

       b)  the ISP is multi-homed, that is, it has more than one
           simultaneous connection to the global Internet and no
           connection is favored over the other

   Note that addresses issued directly from the IRs, (non-provider
   based), are the least likely to be routable across the Internet.

The following are the IP allocation guidelines for ISPs:

1.     CIDR addresses are allocated to ISPs in blocks.  It is
       recommended that those blocks remain intact.  Fragmentation  of
       CIDR blocks is discouraged.  More specifically, ISPs are
       encouraged to treat address assignments as loans for the
       duration of the connectivity provision.  At the termination
       of the Internet connectivity contract, e.g., the customer
       moves to another service provider, it is recommended the
       customer return the network addresses currently in use and
       renumber into the new provider's address space.  The ISP
       should allow sufficient time for the renumbering process to be
       completed before the IP addresses are reused.

Expiration Date May 1996                                [Page 5]

2.     To ensure efficient implementation and use of Classless
       Inter-Domain Routing (CIDR), the Regional Registries issue
       address space on appropriate "CIDR-supported" bit boundaries.
       ISPs will also be made aware of the procedures that define bit
       boundary IP address allocation, and they must use these
       procedures when allocating IP address space to their respective
       customers if offering portable address space.  Please note, in
       this document "portable" is used to describe addresses that
       are permitted to be removed from an ISP CIDR block.

 3.    ISPs are required to utilize address space in an efficient
       manner.  To this end, registries should have documented
       justification available for each assignment.  The parent registry
       may, at any time, ask for this information.  If the information
       is not available, future allocations may be impacted.

4.     IP addresses are allocated to ISPs using a slow-start
       procedure.  New ISPs will receive a minimal amount based
       on immediate requirement.  Thereafter,  allocated blocks may be
       increased based on utilization verification supplied to the
       regional registry.  The parent registries are responsible for
       determining appropriate initial and subsequent allocations.
       Additional address allocations will provide enough address space
       to enable the ISP to assign addresses for three months
       without requesting additional address space from their parent
       registry.  Please note that projected customer base has little
       impact on the address allocations made by the parent registries.
       Initial allocation will not be based on any current or future
       routing restrictions but on demonstrated requirements.

 5.    Due to the requirement to increase the utilization efficiency
       of IPv4 address space, all assignments are made with the
       assumption that sites make use of variable length subnet mask
       (VLSM) and classless technologies within their network.  Any
       request for address space based on the use of classfull assumptions
       will require a detailed justification.  The use of classfull
       technologies for the purposes of administrative convenience is
       generally insupportable due to the limited availability of free
       IPv4 address space.

 6.    Regional registries may set a maximum limit on assignment sizes
       such that a second opinion of the regional registry is required.

 Expiration Date May 1996                                [Page 6]

 7.    Due to constraints on the available free pool of IPv4 address
       space, the use of static IP address assignments (e.g., one
       address per customer) for dial-up users is strongly discouraged.
       While it is understood that the use of static addressing may
       ease some aspects of administration, the current rate of
       consumption of the remaining unassigned IPv4 address space does
       not permit the assignment of addresses for administrative ease.
       Organizations considering the use of static IP address assignment
       are expected to investigate and implement dynamic assignment
       technologies whenever possible.

2.2  Submission of Reassignment Information

 It is imperative that reassignment information be submitted in a prompt
 and efficient manner to facilitate database maintenance and ensure
 database integrity.  Therefore, assignment information must be
 submitted to the regional registry immediately upon making the
 assignment.  The following reasons necessitate transmission of the
 reassignment information:

       a)  to provide operational staff with information on who is using
           the network number and to provide a contact in case of
           operational/ security problems,
       b)  to ensure that a provider has exhausted a majority of its
           current CIDR allocation, thereby justifying an additional

       c)  to assist in IP allocation studies.

 Procedures for submitting the reassignment information will be
 determined by each regional registry based on its unique requirements.

 All sub-registries (ISPs, Local registries, etc.) must register with
 their respective regional registry to receive information regarding
 reassignment guidelines.  No additional CIDR blocks will be
 allocated by the regional registry or upstream providers until
 approximately 80% of all reassignment information has been submitted.

Expiration Date May 1996                                [Page 7]

                            III. ASSIGNMENT FRAMEWORK

 An assignment is the delegation of authority over a block of IP
 addresses to an end enterprise.   The end enterprise will use
 addresses from an assignment internally only; it will not sub-delegate
 those addresses.  This section discusses some of the issues involved in
 assignments and the framework behind the assignment of addresses.

 In order for the Internet to scale using existing technologies,
 use of regional registry services should be limited to the
 assignment of IP addresses for organizations meeting one or
 more of the following conditions:

      a)  the organization has no intention of connecting to
          the Internet-either  now or in the future-but it still
          requires a globally unique IP address.  The organization
          should consider using reserved addresses from RFC1597.
          If it is determined this is not possible, they can be
          issued unique (if not Internet routable) IP addresses.

      b)  the organization is multi-homed

      c)  the organization's request is very large, for example,
          the network prefix required to cover the request is
          of length /18 or shorter.

 All other requestors should contact their ISP for address
 space or utilize the addresses reserved for non-connected networks
 described in RFC1597 until an Internet connection is established.
 Note that addresses issued directly from the IRs,(non-provider based),
 are the least likely to be routable across the Internet.

 3.1  Common Registry Requirements

 Because the number of available IP addresses on the Internet is
 limited,  the utilization rate of address space will be a key factor
 in network number assignment.  Therefore, in the best interest of the
 Internet as a whole, specific guidelines have been created to govern
 the assignment of addresses based on utilization rates.

Expiration Date May 1996                                [Page 8]

 Although topological issues may make exceptions necessary, the basic
 criteria that should be met to receive network numbers are listed

                25% immediate utilization rate
                50% utilization  rate within 1 year

 The utilization rate above is to be used as a guideline, there may be
 be occasions when the 1 year rate does not fall exactly in this range.
 Organizations must exhibit a high confidence level in their 1 year
 utilization rate and supply documentation to justify their level of

 Organizations will be assigned address space based on immediate
 utilization plus 1 year projected utilization.  A prefix longer than
 /24 may be issued if deemed appropriate.  Organizations with less than
 64 hosts will not be issued an IP address directly from the IRs.
 Organizations may be issued a prefix longer than /24 if the
 organization can provide documentation from a registry recognized
 ISP indicating the ISP will accept the long prefix for injection
 into the global routing system.

 Exceptions to the criteria will not be made based on insufficient
 equipment without additional detailed justification.  Organizations
 should implement variable length subnet mask (VLSM) internally to
 maximize the effective utilization of address space.  Address
 assignments will be made under the assumption that VLSM is or will
 be implemented.

 IP addresses are valid as long as the criteria is met.  The IANA
 reserves the right to invalidate any IP assignments once it is
 determined the the requirement for the address space no longer exists.
 In the event of address invalidation, reasonable efforts will be made
 by the appropriate registry to inform the organization that the
 addresses have been returned to the free pool of IPv4 address space.

 3.2  Network Engineering Plans

 Before a registry makes an assignment, it must examine each address
 space request in terms of the requesting organization's networking
 plans.  These plans should be documented, and the following information
 should be included:

      1.  subnetting plans, including subnet masks and number of
          hosts on each subnet for at least one year

Expiration Date May 1996                                [Page 9]

      2.  a description of the network topology

      3.  a description of the network routing plans, including the
          routing protocols to be used as well as any limitations.

 The subnetting plans should include:

      a)  a tabular listing of all subnets on the network

      b)  their associated subnet masks

      c)  the estimated number of hosts

      d)  a brief descriptive remark regarding the subnet.

 If subnetting is not being used, an explanation why it cannot be
 implemented is required.  Care must be taken to ensure that the host
 and subnet estimates correspond to realistic requirements and are not
 based on administrative convenience.

 3.3  Previous Assignment History

 To promote increased usage of address space, the registries will
 require an accounting of address space previously assigned to the
 enterprise, if any.  In the context of address space allocation, an
 "enterprise" consists of all divisions and/or subsidiaries falling
 under a common parent organization.  The previous assignment history
 should include all network numbers assigned to the organization,
 plus the network masks for those networks and the number of hosts
 on each (sub-)network.  Sufficient corroborating evidence should be
 provided to allow the assigning registry to be confident that the
 network descriptions provided are accurate.

 3.4  Network Deployment Plans

 In order to assign an appropriate amount of space in the required time
 frame, a  registry  may request deployment plans for a network.
 Deployment plans should include the number of hosts to be deployed per
 time period, expected network growth during that time period, and
 changes in the network topology that describe the growth.

Expiration Date May 1996                                [Page 10]

 3.5  Organization Information

 A registry may request that an organization furnish a published
 description verifying that the organization is what it claims to be.
 This information can consist of brochures, documents of incorporation,
 or similar published material.

 3.6  Expected Utilization Rate

 As stated in the foregoing text, one of the key factors in determining
 how much address space is appropriate for an organization is the
 expected utilization rate of the network.  The expected utilization
 rate is the number of hosts connected to the network divided by the
 total number of hosts possible on the network.  In addition, the
 estimated number of hosts should be projected over a reasonable time
 frame, i.e., one in which the requesting enterprise has a high level
 of confidence.  The minimal utilization rate is set by the IANA and
 may be changed at any time.  New utilization rates may be enforced by
 the regional registries prior to updating the written policy.


 1.    Regional Registries provide registration services as their
       primary function.  Therefore, regional registries may charge some
       fee for services rendered, generally in relation to the cost of
       providing those services.

2.     Regardless of the source of their address space, sub-registries
       (Local IRs, ISPs, etc.) must adhere to the guidelines of their
        regional registry.  In turn, they must also ensure that their
       customers follow those guidelines.

 3.    To maximize the effective use of address space, IP addresses need
       to be assigned/allocated in classless blocks.  With this in mind,
       assignments will not be made in Class Cs or Bs but by prefix
       length.  Consequently, an organization that would have been
       assigned a Class B in the past will now be assigned a /16 prefix,
       regardless of the actual address class.

 4.    All IP address requests are subject to audit and verification
       by any means deemed appropriate by the regional registry.
       If any assignment is found to be based on false information,
       the registry may invalidate the request and return the
       assigned addresses back to the pool of free addresses for
       later assignment.

Expiration Date May 1996                                [Page 11]

 5.    Due to technical and implementation constraints on the Internet
       routing system and the possibility of routing overload, major
       transit providers may need to impose certain restrictions to
       reduce the number of globally advertised routes.  This may
       include setting limits on the size of CIDR prefixes added to
       the routing tables, filtering of non-aggregated routes, etc.
       Therefore, addresses obtained directly from regional registry
       (provider-independent, also known as portable) are not
       guaranteed routable on the Internet.

 6.    Information provided to request address space is often considered
       sensitive by the requesting  organization.  The assigning
       registry must treat as confidential any and all information
       that the requesting organization specifically indicates as
       sensitive.  When a requesting organization does not have
       assurance of privacy, the parent of the assigning registry may
       be required to do the assignment.  In such cases, the parent
       registry will provide the assigning registry with information
       regarding the appropriate amount of address space to allocate.

7.    The transfer of IP addresses from one party to another must be
      approved by the regional registries.  The party trying to obtain
      the IP address must meet the same criteria as if they were
      requesting an IP address directly from the IR.

              V.  In-ADDR.ARPA Domain Maintenance

 The regional registries will be responsible for maintaining
 IN-ADDR.ARPA records only on the parent blocks of IP addresses issued
 directly to the ISPs or those CIDR blocks of less than /16.  Local
 IRs/ISPs with a prefix length of /16 or shorter will be responsible
 for maintaining all IN-ADDR.ARPA resource records for their customers.

 IN-ADDR.ARPA resource records for networks not associated with a
 specific provider will continue to be maintained by the regional

                      VI.  Right to Appeal

 If an organization feels that the registry that assigned its address
 has not performed its task in the requisite manner, the organization
 has the right of appeal to the parent registry.

 In such cases, the assigning registry shall make available all relevant
 documentation to the parent registry, and the decision of the parent
 registry shall be considered final (barring additional appeals to the
 parent registry's parent).

Expiration Date May 1996                                [Page 12]

VII.  References

[RFC 1519] V. Fuller, T. Li, J. Yu, K. Varadhan,
   "Classless Inter- Domain Routing (CIDR): an Address
   Assignment and Aggregation Strategy".

[RFC 1518] Y. Rekhter, T. Li, "An Architecture for IP
   Address Allocation with CIDR".

[RFC 1597] Y. Rekhter, B. Moskowitz, D. Karrenberg, G. de Groot,
 "Address Allocation for Private Internets".

VIII. Authors' Addresses

    Kim Hubbard
    InterNIC Registration Services
    c/o Network Solutions
    505 Huntmar Park Drive
    Herndon, VA 22070
    Phone: (703) 742-4870
    email: kimh at

    Mark Kosters
    InterNIC Registration Services
    c/o Network Solutions
    505 Huntmar Park Drive
    Herndon, VA 22070
    Phone: (703) 742-4795
    email: markk at

    David Conrad
    Asia Pacific Network Information Center
    c/o United Nations University
    53-70 Jingumae 5-chome,
    Shibuya-ku, Tokyo 150
    Phone: +81-3-5467-7014
    email: davidc at APNIC.NET

    Daniel Karrenberg
    Kruislaan 409
    SJ Amsterdam NL-1098
    Phone: +31 20 592 5065
    email: dfk at RIPE.NET

Expiration Date May 1996                                [Page 13]

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