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[AFRINIC-rpd] IPv4 Address Allocation and Assignment proposal

sm+afrinic at sm+afrinic at
Tue Jan 22 15:45:47 UTC 2013


This proposal is about IPv4 address allocations and assignments in 
the AfriNIC service region.  It incorporates the experience gained in 
allocating IPv4 addresses since 2006.

S. Moonesamy
-------------- next part --------------
Name: S. Moonesamy
Email: sm+afrinic at
Date: 22 January, 2012
Obsoletes: AFPUB-2005-v4-001
Version: 1

Title: IPv4 Address Allocation and Assignment


This document describes the policy for IPv4 Address allocations and
assignments in the AfriNIC service region.

1. Introduction

AfriNIC (African Network Information Center) is the Regional Internet
Registry (RIR) for the AfriNIC service region.  It is responsible for the
allocation of IPv4 address space within the African service region.

The Internet Assigned Numbers Authority (IANA) allocates parts of the IPv4
address space to AfriNIC for distribution within the AfriNIC service region.
This document describes the policy for IPv4 Address allocation and assignments
in the AfriNIC service region.

The first policy for IPv4 address allocation (AFPUB-2005-v4-001) was adopted
in May 2006.  This document incorporates the experience gained in allocating
IPv4 addresses since 2006. It obsoletes AFPUB-2005-v4-001.

2. Definitions

2.1 IPv4 Addresses

IPv4 addresses are fixed length of four octets (32 bits).  This document
refers to IPv4 addresses administered by AfriNIC as documented in the IANA
IPv4 Address Space Registry [REG].

2.1 Internet Registry

An Internet Registry is an organization that is responsible for distributing
IP address space to its customers and for registering those addresses.
Internet Registries are classified according to their primary function.

2.2. Regional Internet Registry

A Regional Internet Registry (RIR) operates within a large geopolitical region
such as a continent.  The purpose of a Regional Internet Registry is to manage
and distribute Internet number resources within its service region.

2.3 Local Internet Registry

A Local Internet Registry (LIR) is an Internet Registry that receives
allocations from an RIR and primarily assigns address space to the users
of the network services it provides.   The users are end users and possibly
other Internet Service Providers.

2.5 Internet Service Provider

An Internet Service Provider (ISP) assigns IP address space to the end users
of a network service it provides.  Its customers can be other ISPs.

2.6 End User

An end user or end site has a legal or commercial relationship (the same or
associated entities) with an Internet Service Provider.

2.7 Allocate

Allocate refers to the distribution of IP address space to Local Internet
Registries for the purpose of subsequent distribution.

2.8 Sub-Allocate

To "sub-allocate" means to IP address space distribute by Local Internet
Registries to ISPs for the purpose of subsequent distribution.

2.8. Assign

Assign means to delegate IP address space to an Internet Service Provider or
End User for their operations.

Assignments must only be made for specific purposes documented by the
organisations and are not to be sub-assigned to other parties.

2.9 Provider Aggregatable IP Address Space

Provider Aggregatable IP address space is IP address space which has been
allocated to LIRs from which they can assign or sub-allocate to end users,
downstream networks as a non-portable block.  If the end user or downstream
network changes provider (LIR), the IP address space assigned or sub-allocated
by the previous provider (LIR) should be returned and the network renumbered.

2.10 Provider Independent IP Address Space

Provider Independent (or portable) IP address space cannot be aggregated
and can only be assigned by a RIR through an LIR.  Provider Independent (PI)
IP address space is expensive to route and might not be globally routable.
Sub-allocations cannot be made from this type of IP address space by the
end user or LIR.

3. Internet Registry System

The Internet Registry system consists of the following levels of hierarchy as
seen from the top down: IANA, Regional Internet Registries, Local Internet
Registries.  The Internet Registry system ensures the uniqueness of Internet
number resources and provides information for Internet troubleshooting at
all levels.

4. Goals

AfriNIC has the duty to act as a custodian of a public resource in its
administration of IPv4 address space.  It shall ensure that IPv4 address
space is distributed according to the following goals:

  - Uniqueness
  - Fair distribution
  - Aggregation

  - Registration

4.1 Uniqueness
In order for each host on the public Internet to be addressable each public
unicast IPv4 address must be globally unique.
4.2 Fair distribution
IPv4 addresses shall be distributed fairly according to operational needs
while taking into account that IPv4 addresses is a finite resource.

4.3 Aggregation

Distributing IPv4 addresses in a hierachical manner permits the aggregation of
routing information.  This helps to ensure proper operation of Internet
routing, and to limit the expansion of Internet routing tables.

4.4 Registration

Every assignment and allocation of IPv4 address space shall be registered in
the AfriNIC Whois.  This is necessary to ensure uniqueness, transparency
and to provide information for Internet troubleshooting at all levels.

4.5 Conflicting Goals

It is in the interest of the Internet community as a whole that the above
goals be pursued.  However, fair distribution and aggregation are
conflicting goals.  All the above goals may occasionally be in conflict with
the interests of individual Internet Registries or end users.  Internet
Registries evaluating requests for allocations and assignments must carefully
analyze all relevant considerations to seek an appropriate compromise.

5. Documentation

The decision-making process for each allocation or assignment shall be
documented to ensure that the process is fair.  Documentation should conform
to well-known practices.  Estimates and predictions must be realistic and

5.1 Language

AfriNIC uses English as its working language.

6. Registration Requirements

An allocation or assignment is valid as long as the criteria on which the
original allocation or assignment was based are still in place, the purpose
for which the request was made has not changed, and it is registered in the
AfriNIC Whois.  The registration data (name, range, contact information,
status, etc.) must be kept up-to-date.

An unregistered assignment, allocation, or sub-allocation is considered as

6.1 Cancelling a Registration

Any of the following may be considered as grounds for cancelling a

 (a) Failure to use the IPv4 address space within a period of one month
     following its registration.

 (b) Failure to comply with AfriNIC contractual obligations.

 (c) Failure to adhere to documented AfriNIC community decisions.
AfriNIC shall inform the community that the IPv4 address block is once again

7. IPv4 Address Allocation Guidelines

An IPv4 allocation is a range of IPv4 addresses from which assignments or 
sub-allocations are made.

In an effort to ensure that Classless Inter-Domain Routing (CIDR), as
described in BCP 122 [BCP122], is implemented and utilized as efficiently as 
possible, AfriNIC will issue blocks of IPv4 addresses on appropriate
"CIDR-supported" bit boundaries.

A LIR assigning IPv4 address space allocated by AfriNIC must adopt policies
that are consistent with this document.

7.1 Initial Allocation

The minimum initial allocation is a /22 IPv4 address prefix length.

Justification is based on a combination of immediate need and existing usage
of IPv4 addresses.  Existing assignments of IPv4 addresses should be
renumbered into the LIR's new allocation.

Verification of existing usage of IPv4 addresses is based on assignments
and sub-allocations registered in the AfriNIC, APNIC, ARIN, LACNIC and RIPE
Whois and only these registered assignments will be considered as valid.

A minimum initial allocation may also be considered if an Internet Service
Provider interconnects with other networks at an Internet Exchange Point in
the AfriNIC service region which has an open policy.  Additional information
may be requested to justify the allocation.

7.2  Slow Start Mechanism For Initial Allocations

The slow start mechanism is to prevent allocations of large blocks of IPv4
address space that may then remain substantially unassigned.

A slow start mechanism shall be applied for to a new LIR.  The initial
allocation made by AfriNIC to an LIR will be the size of the IPv4 address
prefix described in Section 7.1 unless otherwise justified.

7.3 Additional Allocation

Requests for an additional allocation will be considered if about 80% of all
the IPv4 address space currently allocated to the LIR has been used for valid
assignments and/or sub-allocations.  A new allocation request can also be
considered if an assignment or sub-allocation requires more addresses
than the amount of IPv4  addresses currently held by the LIR.

Reservations are not considered as valid assignments or sub-allocations.  It
may be useful for internal aggregation to keep some IPv4 address blocks free
for future growth.  These internal reservations are however not considered
as valid usage and must be assigned or sub-allocated before requesting an
additional allocation.

Contiguous IPv4 address ranges should be allocated to allow the LIR to
minimise the number of route announcements it makes.  However, it may not
always be possible to allocate an IPv4 address range contiguous with the
LIR's previous allocation.

7.4 Sub-Allocations

The minimum IPv4 address prefix length of a sub-allocation is a /24.  It
allows a reasonable number of small assignments to be made by a downstream
ISP.  A LIR may not sub-allocate IPv4 address space above its suballocation
window (see Section 9 for sub-allocation window).

LIRs may make sub-allocations to multiple downstream ISPs. (Downstream ISPs
efficiently using a sub-allocation qualify to receive a /22 IPv4 address
prefix length should they want to become an LIR).

The LIR is responsible for ensuring that IPv4 address space allocated to it,
and subsequently, the IPv4 address space that it sub-allocates, is used in
accordance with documented AfriNIC community decisions [PDP].

It is recommended that LIRs make use of the slow-start mechanism for
sub-allocations to downstream ISPs.  It is to ensure that the IPv4 address
space sub-allocated is used efficiently.  It can help the LIR determine
whether the downstream ISPs are operating according to documented
AfriNIC community decisions.

Sub-allocations are part of a LIR's aggregatable IPv4 address space.  A
LIR shall ensure that IPv4 address space is not sub-allocated to a
downstream ISP if the downstream ISP is not longer connected to the LIR's
network (sub-allocations are non-portable).

7.5 Maximum Allocation

The recommended maximum allocation is a /10 IPv4 address prefix length.

8. IPv4 Assignment Guidelines

A LIR must obtain approval from AfriNIC approval for all sub-allocations above
its Sub-Allocation Window (see Section 9 for Sub-Allocation Window).

When a LIR makes a sub-allocation from its Sub-Allocation Window, it must
provide the information to the end user.

AfriNIC may request information about IPv4 addressing needs, network
infrastructure and future plans to verify an end user's IPv4 address
requirements.  In order to ensure that previous sub-allocations are not 
duplicated, information about existing IPv4 address space usage is required.

The amount of information required depends on the size of the request and
complexity of the network.  Guidance to facilitate requests should be publicly

8.1 Utilisation

Immediate utilisation of assignments should be at least 25% of the assigned
IPv4 address space.  After one calendar year, unless there are special
circumstances, it should be at least 50%.

8.2 Reservations not supported

End users cannot reserve IPv4 address space based on long term plans as this
affects fair distribution and fragments the IPv4 address space when initial
forecasts are not met.  A LIR assigning IPv4 address space to end users must
make the assignments from any unallocated or unassigned address space it
currently holds.  All IPv4 address space reserved by an LIR for its end users
is considered as unused.

8.4 Re-numbering

Valid assignments can be replaced with the same number of IPv4 addresses if
the original assignment criteria are are still met.  The IPv4 addresses
to be replaced must still be in use.  When a renumbering request exceeds the
LIR's sub-allocation window, the request should be sent to AfriNIC for

A LIR will be given a period of up to three months to migrate to the new IPv4
address space.  The LIR may request additional time if there is appropriate
justification.  Once a network has been renumbered, AfriNIC will remove the
old assignment from the AfriNIC Whois.

8.5 Network Infrastructure of LIR vs End User Networks

IPv4 addresses used solely for connecting an end user to an LIR (e.g.,
point-to-point links) are considered as part of the LIR's infrastructure.
These addresses should be registered as part of the LIR's infrastructure.

Sub-allocations made by a LIR to an end user must be registered in AfriNIC
Whois.  This IPv4 address space must be registered with the contacts
of the end user.  If the end user is an individual rather than an
organisation the IPv4 address space may be registered with the contact
information of the LIR but with the end user referenced in the AfriNIC Whois
database object.

9. Sub-Allocation Window

A sub-allocation window (SAW) refers to the maximum number of IPv4 addresses
that the LIR may sub-allocate to the end users without seeking approval from
AfriNIC.  The SAW size is expressed in CIDR notatation.  AfriNIC shall review
the sub-allocation made by the LIR using its SAW for compliance.

A LIR should ensure that documentation for sub-allocation made using the SAW
be similar to that requested for larger requests.

9.1 Sub-Allocation Window Guidelines

The guidelines for the sub-allocation window (SAW) are as follows:

  (a) A new LIR has a SAW of zero.  The LIR shall request approval from
       AfriNIC for sub-allocations.

  (b) A LIR cannot make any sub-allocation to the end user above their
      SAW in a 12 months period (one calendar year).  At the end of a
      calendar year from the approval of a SAW, the SAW is refreshed
      for one more calendar year.  In case the LIR's SAW is exhausted
      for a particular end-user, approval must be sought from AfriNIC
      for any other sub-allocation to the same end-user.

  (c)  A LIR can ask AfriNIC to review their SAW.  They may also seek a 
       second opinion from AfriNIC even for a sub-allocation that could
       be made with their SAW if they chose.  Before a SAW is raised the
       following shall be considered:

       (i)   All required documentation is normally presented.

       (ii)  Previous sub-allocation assignments from this sub-allocation
             are all registered in the database correctly.

       (iii) The current SAW has not been misused or abused.

A LIR should ensure that its end users handle IPv4 address space assignments
according to this document.  If errors occur repeatedly the SAW may be
lowered or removed.  The SAW may also be lowered or removed during or after
an audit if invalid assignments are noted.

10. Record keeping

A LIR shall keep and maintain records regarding assignments and
sub-allocations to its end users.  These records may be used to evaluate
requests made by the LIR or for any audits performed by AfriNIC.  For
convenience, the records should be accessible in an electronic format. It is
recommended that the records include but are not be limited to:

 (a) The original request.
 (b) Supporting documentation.
 (c) Related correspondence between LIR and end user.
 (d) The assignment decision, including the reasons for any unusual decision.

 (e) Role of the person who made the decision.
The history of events and the persons responsible should be clear.

11. Acknowledgements

The author would like to thank Adiel A. Akplogan and Ernest Byaruhanga for
most of the text which were copied from AFPUB-2005-v4-001.

12. References

[REG]   IANA IPv4 Address Space Registry

[BCP122] Classless Inter-domain Routing (CIDR): The Internet Address
         Assignment and Aggregation Plan,
[PDP]    Policy Development Process in the AfriNIC service region

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