IPv4 Depletion and IPv6 Deployment FAQs
IPv4 Depletion
1. What is meant by IPv4 "running out"?
IP address space (both IPv4 and IPv6) is distributed globally by the Regional
Internet Registries (RIRs), including the RIPE NCC. The RIRs distribute these addresses from a
pool of addresses that have, so far, not been allocated to End Users or
reserved for any other purpose. This "free pool" is overseen
by the Internet Assigned Numbers Authority (IANA).
The total size of the IPv4 address pool is determined by the fact that
IPv4 addresses are 32-bit numbers. This means that there are 232 (or just
over four billion) unique IPv4 addresses. When an ISP wishes to provide
its customers with IP addresses, it can obtain an allocation of addresses
from its RIR. The Internet community has now reached a point where most
of the available four billion IPv4 addresses have been allocated for use
or reserved for a specific technical purpose.
The exhaustion of the IPv4 free pool will not mean that the Internet
ceases to work. All of the four billion addresses that have previously
been allocated will still operate as they always have. It will mean a significant
change, however, to the global IP address distribution system, and to the
role of the RIRs, at least in relation to IPv4 addresses.
2. When will this happen?
Exhaustion of unused IPv4 address space will not happen suddenly. There
will be at least three identifiable stages in the process:
- The IANA will run out of unused address space to allocate to RIRs.
- The RIRs will run out of unused address space to allocate to LIRs.
- LIRs will run out of unused address space to assign to End Users.
Various people and organisations are keeping close watch on trends in
IPv4 exhaustion rates, and the most widely accepted prediction places IANA
exhaustion somewhere around 2011. APNIC Chief Scientist Geoff Huston maintains a website with an up-to-date prediction:
http://www.potaroo.net/tools/ipv4/index.html
3. Under what policies will the final blocks of IPv4 space be
distributed?
The policies under which the final unused blocks of IPv4 address space
will be allocated by the IANA are currently under discussion in the different
RIR communities. Such a policy would have to be global, and would therefore
require the consensus agreement of all RIR communities.
You can still provide your input to this discussion through the policy
development forums of your RIR.
4. If I can't get IPv4 addresses from an RIR, can I buy an IPv4
address allocation from someone else?
Under the current IPv4 distribution system, IP addresses are regarded
as a public resource and cannot be bought or sold. If it is not possible
to obtain address space from an RIR, then an ISP can still obtain addresses
from an upstream ISP, but the addresses should remain registered to that
upstream ISP.
Obviously the exhaustion of unused IPv4 addresses will mean significant
changes to this system, as it will no longer be possible to obtain IPv4
address space directly from an RIR. What changes will be implemented are
still being discussed in the RIR communities, but it seems likely that
a system will emerge to enable the transfer of address allocations between
LIRs. One such policy currently under discussion in the RIPE community
is proposal 2007-08, Enabling Methods for Reallocation of IPv4 Resources:
http://www.ripe.net/ripe/policies/proposals/2007-08.html
5. What are the RIRs doing to prepare for the possible emergence
of transfers?
The RIPE community and the RIPE NCC are currently involved in a range
of activities to plan for changes to the IPv4 address distribution system.
As well as discussing policy proposals such as the 2007-08 within
the community, the RIPE NCC is engaging with organisations such as the Organisation
For Economic Co-ordination And Development (OECD) to better understand
the economic and political effects of such changes.
Whatever new policies are adopted, there are certain considerations that
are vital to the ongoing stability of the Internet. Policies must:
a. Ensure the accuracy and accountability of registration data
b. Prevent the fragmentation of address space
You can have input into the development of these policies through the
discussion forums of your RIR.
6. Are there any alternative strategies for dealing with IPv4 exhaustion?
There are existing technical solutions (and further solutions in development)
that can reduce the need for unique, unused IPv4 addresses. These include
various forms of address translating technologies, application level gateways and
new addressing schemes. The common drawback of these approaches is that
in many cases they violate the end-to-end principle, making networks more
difficult to troubleshoot and hindering future development of the Internet.
Also, most of them still require a free IPv4 address pool.
The preferred option for the continuing expansion and development of the
Internet is the global deployment of IPv6.
IPv6 Deployment
1. What is IPv6?
Internet Protocol version 6 (IPv6) is a protocol that has been designed
by the Internet Engineering Task Force (the IETF) to supplement, and eventually
replace, the current Internet Protocol version 4 (IPv4). The most important
aspect of IPv6 is that is offers a vast number of unique IP addresses.
Compared to IPv4, which has a theoretical maximum of around four billion
IP addresses, IPv6 provides a theoretical maximum of 340 trillion, trillion,
trillion IP addresses. This is because IPv6 addresses consist of 128 bits,
whereas IPv4 addresses are made up of just 32 bits.
Although it has been available since 1999, IPv6 is becoming an increasingly
important resource with the expected depletion of IPv4 addresses.
2. What does the adoption of IPv6 entail?
There are three important elements necessary for the widespread adoption
of IPv6: the IPv6 protocol, IPv6-enabled products and IPv6 operational
practices.
The protocol has been developed within the IETF for more than 10 years,
which means that the core standards are stable and have been well tested
in research and operational contexts.
Widespread adoption of IPv6 relies on a strong demand from consumers encouraging
vendors to provide an increasing range of IPv6-enabled products and services.
While IPv6 hardware and software products are becoming increasingly available,
there are still many non-IPv6 compatible products on the market and in
circulation. It is expected that this will change as IPv6 traffic increases.
This transition will not happen overnight, and there will be a sustained
period where IPv4 and IPv6 will be running in parallel. IPv6 and its transition
mechanisms have been designed for a long period of co-existence with IPv4
and it is expected that IPv4-only systems and applications will continue
to operate on the Internet for a number of years.
At an operational level, various technologies exist to ensure the interoperability
of IPv4 and IPv6 networks. These technologies include "tunneling",
which enables IPv6 packets of data to be moved across the core of the IPv4
network, and "dual stacking", which enables an Internet host
to provide two discrete network layers, one running IPv4 and the other
IPv6.
In summary, IPv6 is ready for deployment, but additional effort is required
to encourage its widespread adoption. As well as government and regulator
representatives, the IETF, equipment vendors, application developers, network
operators and End Users all have important roles to play. As an industry-wide
issue involving both the public and private sectors, the deployment of
IPv6 requires increased communication and cooperation from all parties
in order to ensure the future stability of the Internet.
3. Do IPv6 address management policies differ from the existing IPv4 address management policies?
Yes, but the principles and management process are the same for IPv4 and
IPv6.
There are separate policies for IPv4 and IPv6 address space management,
and the newer IPv6 policies have incorporated the lessons learnt from more
than 25 years of IPv4 policy development. In addition, separate policies are
needed to accommodate the specific technical differences between IPv4 and IPv6.
However, while there are separate policies for IPv4 and IPv6 the address
management process and the principles behind that process are the same.
IP addresses are managed by the Internet Assigned Numbers Authority (IANA),
which has overall responsibility for the IP address pool, and by the Regional
Internet Registries (RIRs) which receive large blocks of IP addresses from
IANA.
The RIRs manage, distribute and publicly register these IP addresses within
their service regions. These activities are performed according to policies developed
within their respective regional communities, through open and bottom-up
processes. These processes enable any group or individual to express their
opinion and to offer their input. Policy decisions are made on a consensus-based
approach.
The IPv4 and IPv6 address management policies are both founded on the principles
of equal access and demonstrated need. The over-riding purpose is to ensure
IP addresses are available to those who can prove they need them.
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