Home / Blogs

IPv4: Business As Usual

This year, we expect that the RIPE NCC’s pool of unallocated IPv4 addresses will reach the “last /8”, meaning that we have 16,777,216 IPv4 addresses left in the available pool. At that point it will no longer be possible for RIPE NCC members to obtain the amount of IPv4 addresses they will require to expand their current and future networks.

When we hit the last /8, the RIPE NCC will only be able to distribute IPv6 addresses and a one-off allocation of IPv4 address space (1,024 IPv4 addresses) from the “last /8” to those members that meet the policy requirements. This will ensure that existing network operators are able to dual stack their networks and that new entrants can make sure their networks and services are available over both IPv4 and IPv6.

Has this caused a last minute rush?

In the image below, you can see the cumulative number of IPv4 addresses assigned or allocated yearly since 2009. Every year is depicted in a different colour. The dots on each curve indicate the number of addresses distributed at the end of each month.

As you can see, the patterns of the four lines are uniform and also surprisingly linear. The curve showing the first four months of 2012 (depicted in black) follows the same pattern even though it is expected that the RIPE NCC reaches the last /8 later this year. A consistent number of addresses have been distributed each month and we haven’t observed a last minute rush for the remaining IPv4 addresses—yet.

It’s good to see that the address space distribution policies set by the RIPE community to ensure that the remaining IPv4 address space is conserved and distributed fairly over the last few years have worked well. You can find more information and motivation about the Run Out Fairly Policy, which was introduced in 2010, on the RIPE NCC website.

The chart shows that reaching the last /8 of IPv4 address space is not coming as a surprise to the community, but that most people are well prepared for it due to the information and education provided over the last several years by the RIPE NCC and the discussions held during the RIPE Meetings and other Internet community meetings.

We can only speculate, but there are two possible interpretations: the industry is well prepared for the exhaustion of IPv4 addresses or it is closing their eyes until we have “chopped down the last tree” as Geoff Huston put it in one of his recent presentations.

For more information, please refer to RIPE Labs.

By Daniel Karrenberg, Chief Scientist at the RIPE NCC

Filed Under


When I ran an ISP back in Phil Howard  –  May 30, 2012 2:08 PM

When I ran an ISP back in the late years of the last millennium, I conserved our use of a /19 allocation by using private IPs (specifically the 172.30/16 space) for all the point to point links that needed a /30.  I did get some flack about it from some outsiders because traceroutes had a dead spot (but not for me, the one who would need to actually do the testing and fixing).  Other than that, it worked fine.  True point to point should not even need numbers, but implementations were, at least then, not handling it.

I also learned how to allocate less to customers that needed less, and make 100% use of it.  I could allocate a /30 to a customer that needed 4 addresses, and all 4 actually worked.  I allocated quite a number of /31 subnets.  The key here is the overhead of a base address and a broadcast address were applicable to physical networks like ethernet, but not to routes.

Later in life I work for a company that gets a /29 from its upstream provider.  I then proceeded to use all 8 addresses without any difficulty.  I really only needed a /30 but they had no means to allocate it.  Further, they also burned a public /30 just to establish the link to our router.  So 12 addresses used when we needed only 3.

I wonder if they were using all that waste to “justify” more space from ARIN.  Unfortunately, “best practices” just were not getting better, so it’s still the norm today.

At least these providers using /30s everywhere have bankrolled a lot of IPv4 space.

Comment Title:

  Notify me of follow-up comments

We encourage you to post comments and engage in discussions that advance this post through relevant opinion, anecdotes, links and data. If you see a comment that you believe is irrelevant or inappropriate, you can report it using the link at the end of each comment. Views expressed in the comments do not represent those of CircleID. For more information on our comment policy, see Codes of Conduct.

CircleID Newsletter The Weekly Wrap

More and more professionals are choosing to publish critical posts on CircleID from all corners of the Internet industry. If you find it hard to keep up daily, consider subscribing to our weekly digest. We will provide you a convenient summary report once a week sent directly to your inbox. It's a quick and easy read.

I make a point of reading CircleID. There is no getting around the utility of knowing what thoughtful people are thinking and saying about our industry.

Co-designer of the TCP/IP Protocols & the Architecture of the Internet



Brand Protection

Sponsored byCSC


Sponsored byVerisign

New TLDs

Sponsored byRadix

Threat Intelligence

Sponsored byWhoisXML API


Sponsored byDNIB.com

Domain Names

Sponsored byVerisign

IPv4 Markets

Sponsored byIPv4.Global