[AfrICANN-discuss] IPv4's Last Day: What Will Happen When There Is Only IPv6?

[Anne-Rachel Inné]

http://www.enterprisenetworkingplanet.com/news/article.php/3878391/IPv4s+Last+Day:+What+Will+Happen+When+There+Is+Only+IPv6?.htm

IPv4's Last Day: What Will Happen When There Is Only IPv6?

April 23, 2010
By Sean Michael Kerner

TORONTO -- How will we know when IPv4 address space is all used up?
And what will happen when that day comes?

The modern Internet has been built using IPv4 (define), which provides
for 4.3 billion address, a supply that could run dry within the next
two years. Organizations that allocate IP address space like the
American Registry for Internet Numbers (ARIN) have attempted to
forecast when IPv4 address space will be gone, but it's not an exact
science, and there is no precise date to mark on a calendar.

At the ARIN XXV policy meetings held here this week, ARIN CIO Richard
Jimmerson explained how the organization expects to know when the
final IPv4 address is gone.

"We will run out of IPv4 address space and the real difficult part is
that there is no flag date. It's a real moving date based on demand
and the amount of address space we can reclaim from organizations,"
Jimmerson told InternetNews.com. "If things continue they way they
have, ARIN will for the very first time, sometime between the middle
and end of next year, receive a request for IPv4 address space that is
justified and meets the policy. However, ARIN won't have the address
space. So we'll have to say no for the very first time."

Saying no to an IPv4 request will be shocking to some organizations,
which is why ARIN is trying to get the word out now on the importance
of moving to IPv6, Jimmerson said. The IPv6 (define) address space,
the next generation of IP addressing, provides 340 trillion trillion
trillion (34 x 10 to the 38th power) Internet addresses.

The first time that ARIN declines an IPv4 address request won't
necessarily be the date that IPv4 is completely exhausted.

"It will be a different date for different sizes and types of
organizations," Jimmerson said. "For instance there are some large
national organizations that make address space requests of big blocks.
They'll be the first ones to come in and we'll have to tell them we
don't have as much as they want and they'll have to take a smaller
block. That will be the first indication."

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For other organizations requesting smaller blocks of a few thousand
addresses, IPv4 may be available for a longer period of time. But
eventually, ARIN will reach the point when it won't be able to fulfill
even small requests, Jimmerson said

To date, the smallest address size allocation ARIN has issued is what
is referred to as a /22 address block, which provides 1,024 IP
addresses. Jimmerson noted that in the future, ARIN may well begin to
offer smaller sized address blocks in the /24 range, which provide 256
IPv4 addresses.

Once the final IPv4 address space that ARIN has available is
allocated, there will still be some extra IPv4 addresses that the
organization will hold in reserve.

"We have some special addresses that we'll hold onto, according to the
policy that has been set," Jimmerson said.

He explained that members of the policy community recognized a few
years back that IPv4 address space was running out. They also
recognized that there would soon be some organizations that would need
to deploy new networks and services on IPv6 without the benefit of
IPv4. As a result, the decision was made to retain some IPv4 address
space so that new networks could put up their IPv4 DNS (define) and
run protocol-translation services.

"So the community set up a policy where we reserve a /10 of IPv4
address space from our final /8 address allocation," Jimmerson said.

A /8 block contains 16,777,214 addresses. The /10 contains 4 million addresses.

"So in the future when we do run out of IPv4 we still have that /10
set aside for organizations that just need a little bit for protocol
translation or DNS," Jimmerson said.

ARIN manages IP address space allocations for the U.S., Canada and the
Caribbean region. ARIN is one of five global Regional Internet
Registry (RIR) organizations that in turn receive their IP allocations
from the Internet Assigned Numbers Authority (IANA). The other four
RIRs are the RIPE Network Coordination Centre (RIPE NCC) for Europe,
the Middle East and Central Asia, the Asia-Pacific Network Information
Centre (APNIC) for Asia and the Pacific region, the Latin American and
Caribbean Internet Addresses Registry (LACNIC) for Latin America and
the African Network Information Centre (AfriNIC) for Africa.

At this point, Jimmerson said that ARIN will still be making IPv4
address space available as long as the supply from IANA holds out.

"There is a global policy that states when the IANA free pool of IPv4
addresses gets down to five /8s remaining they will automatically take
and give one of the remaining /8s to each of the five RIRs," Jimmerson
said.

According to Jimmerson, there are now 20 /8s remaining in the IANA
pool, which makes it likely that ARIN will get more IPv4 address
space. As IPv4 address space nears exhaustion, ARIN has seen the
demand slacken.

"In the ARIN region demand for IPv4 may have leveled off and slowed
down in the last few years," Jimmerson said. "We have a pretty
saturated market with IPv4 address space in North America."

Other areas of the world are still seeing high demand for IPv4 address
space. In particular, the Asia-Pacific and Latin America regions are
experiencing historically high levels of IPv4 address demand,
Jimmerson said.

"For only the second time ever, LACNIC, which services all of South
and Central America, issued more IPv4 address space in the first
quarter of 2010 than ARIN did," he said. "I don't think it has
anything to do with IPv4 depletion -- it's just that the markets are
picking up down there."

Sean Michael Kerner is a senior editor at InternetNews.com, the news
service of Internet.com, the network for technology professionals.