IP Address Space Assignment Procedures (ripe-72++)

Dear IRs













                    European Internet Registry:

               IP Address Space Assignment Procedures



                         Daniel Karrenberg
                          Marten Terpstra

                        Document ID: ripe-xx
                         Obsoletes: ripe-72




                              ABSTRACT

           This document describes the procedures for the
      assignment of IP address space by European local Inter-
      net Registries.



Introduction

The originally centralised procedures for obtaining IP network
numbers from the Global Internet Registry (known as the InterNIC,
previously the DDN NIC) have been replaced by a distributed alloca-
tion scheme.

Blocks of Internet network numbers are now delegated by the Global
Internet Registry to the RIPE NCC, who in turn delegates blocks of
numbers to local Internet Registries (IRs). The local IRs in turn,
make the majority of IP network number assignments across Europe.

The procedures described in this document are designed to ensure
fair distribution and optimal utilisation of the available address
space.
















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Class C Address Space Allocation Procedures


The RIPE NCC currently has been delegated the following class C net-
work number ranges:


                    192.162.0.0 - 192.162.255.0
                    192.163.0.0 - 192.168.255.0

                    193.0.0.0   - 193.255.255.0

                    194.0.0.0   - 194.255.255.0


Local IRs accepting a block of class C numbers agree to adhere to
the following procedures:


 1.  The RIPE NCC will delegate blocks of class C networks to local
     IRs.  Normally the size of a delegation will be 256 contiguous
     networks on a 16-bit boundary.  This can be requested from
     <hostmaster at ripe.net>. If the local registry already has
     delegated blocks a summary of usage of these blocks has to be
     submitted at the same time.


 2.  Full information about reassigned network numbers must be
     reported back to the RIPE NCC in RIPE database format.  The
     complete entries should be sent immediately after assignment,
     certainly not later than one working day after assignment, to
     <auto-assign at ripe.net>.  This will cause the information to be
     included in the RIPE database automatically and an acknowledge-
     ment message to be returned.


 3.  Local IRs are required to have reliable and expedient Internet
     electronic mail connectivity in order to exchange messages
     among themselves, with requestors and with the RIPE NCC.  E-
     mail is the preferred method of communication for registry pur-
     poses, followed by FAX. Paper mail is to be avoided wherever
     possible.  Telephone communications should be confirmed by e-
     mail for documentation purposes and to avoid misunderstandings
     whenever appropriate.


 4.  IRs will keep records of correspondence and information
     exchanges in conjunction with the registry function for later
     review and the resolution of disputes.  IRs will hold this
     information in strict confidence and use it only to review
     requests and in audit procedures or to resolve disputes.





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 5.  Requests for address space should be reasonable and accompanied
     by enough technical details to justify the amount of address
     space requested. If at all possible requesters should be
     encouraged to submit their addressing/subnetting plan because
     this provides an excellent means of assessing whether the
     address space is going to be used effectively.


 6.  Requesters already holding address space are required to list
     the address space they already hold and give a summary of
     current address space utilisation which shows why additional
     address space is needed.  All IRs should prevent stockpiling of
     address space.


 7.  It is recommended that assignment of a block of more than 32
     class C network numbers (13 or more bits of address space)
     should only be made after a second opinion has been obtained
     from the RIPE NCC at <hostmaster at ripe.net>. This second opinion
     shall be documented with the request for later review.


 8.  On first request from the RIPE NCC, the class C network numbers
     not yet reassigned, must be returned to the RIPE NCC.


 9.  The RIPE Database is the only authoritative registry for the
     status of a particular network number from a RIPE NCC delegated
     block. A network number from such a block is considered unas-
     signed if it is not registered in the RIPE database.


 10. Reassignment of class C network numbers should be done in a
     manner that facilitates Supernetting (see next section).


 11. Requests shall be reviewed using Internet-wide guidelines used
     by all Internet registries as described in documents such as
     RFC1466. The local registries shall strive to align their
     review process with other local registries and the RIPE NCC.


 12. Wherever possible IRs should use the European form in order to
     make review and passing of requests between IRs easy. The form
     should be translated and adapted to local circumstances as
     necessary.


Aggregation (CIDR)


IRs reassigning IP network numbers need to be familiar with RFC1519.
This document can be obtained from the RFC section of the RIPE docu-
ment store or other RFC servers.



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Classless addressing aims to reduce the increase of routing table
size in the current Internet.  It creates a hierarchy of IP network
numbers, which can then be aggregated resulting in less routing
table entries in routing equipment.  This proposal has formally been
adopted by the IAB/IESG/IETF, and it has an impact on the address
assignment strategy, which is documented in RFC1466 and RFC1467.

Here is how it works:

If an organisation A needs 8 class C network numbers, the numbers
should be given out in such a way that the routing information for
each of these 8 networks could appear as one entry with the correct
mask in routing tables.

More concretely:

Service provider S hands out networks 192.24.8 through 192.24.15 to
organisation A. These networks can then appear in routing equipment
as a supernet route to 192.24.8 with mask 255.255.248.0.  This way 8
class C network numbers appear as one routing table entry.

The guidelines that can be derived from the Supernetting proposal
are:


 1.  IRs shall allocate class C network numbers in blocks suitable
     for aggregation.  The blocks should be bit-aligned, i.e.  con-
     tiguous, size a power of 2 and start on a multiple of the block
     size.


 2.  The blocks allocated to an organisation should be sufficient
     for a reasonable expected growth over the immediate future.
     Gaps caused by rounding to the next reasonably sized CIDR block
     can be reserved for the organisation holding the preceeding
     addresses.  Note that this differs from earlier recommendations
     to reserve address space for expected growth in the medium
     term.


 3.  Multi-homed organisations may obtain address space from one of
     their providers, the RIPE NCC, or the global NIC, as is
     appropriate to their network configuration. These organisations
     are strongly encouraged to contact the RIPE NCC for guidance.



Class B Network Number Allocation Procedure


European organisations can obtain class B networks numbers from the
RIPE NCC only.  Local IRs and end-user organisations can request
Class B network numbers on a case-by-case basis from the RIPE NCC.
It is preferred if requests are channeled via the local IRs



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initially. The procedures are similar to the class C  procedures
outlined above which apply wherever applicable. In addition the fol-
lowing extra considerations have to be made:


 1.  Because class B address space is a critical resource, a request
     for a class B network number must be accompanied by a justifi-
     cation in terms of the requesting organisation's size, current
     network size and expected network growth.  Submission of the
     addressing/subnetting plan detailing the proposed use of the
     address space is mandatory.


 2.  The requester should also make clear why they cannot use a
     block of class C network numbers to achieve their goals.


Please see the European IP Network Number Application Form for more
details on class B network number requests.  This form must be used
for class B address space requests.


Class A Network Number Allocation Procedure


Class A network numbers are assigned extremely rarely and only in
cases where there is a technical need to have more than 65000 hosts
on a single physical network. Review takes place on a global scale
and takes considerable time. If you are convinced you need a class A
network number, please contact the NCC.



If you have any questions concerning this, please do not hesitate to
call or mail us at hostmaster at ripe.net.






















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