This is an archive page of an article written by the RIPE NCC in 2003.

IPv4 - Running Out of Time? (Summary)

News articles suggest we will soon run out of IP addresses. This will hit the continued growth of the Internet and on-line services. IPv4 provides around 4.4 billion unique IP addresses. The Internet has, however, grown faster than anyone expected.

The Internet Assigned Numbers Authority (IANA) looks after the remaining pool of around sixteen million addresses. Regional Internet Registries (RIRs) request blocks of address space when needed. By the middle of 2003, 90 of the initial 221 blocks were still available.

It became clear that space might one day run out. The Internet Engineering Task Force (IETF) took on the task of finding some solutions. Several responses were put forward to buy time.

A study of trends based on early data is not always reliable. In the early days of the Internet, address allocation was far less controlled than it is today.

These days, the RIRs, guided by IANA policy, handle IP address distribution. When IPv4 address space finally "runs out", it will happen worldwide. Each region will be left with a small pool of free addresses.

The Internet is still growing quickly. Any estimate of when addresses might run out assumes that there will be no major change in either technology or policy.

A possible form of disruption could be a change in how addresses are handed out.

One idea is to use the same system employed by telephone companies. Number blocks are passed to national bodies; onward division is a matter of local policy. This would increase the number of 'holding' points in the system. The current model has been effective in limiting the amount of wasted space.

This is not to say that we have ‘forever’. Plans are now in place to find a new way of handing out addresses and reclaiming 'wasted space' ahead of the pool running out.