Following the recent media stories suggesting that the Internet might be ‘running out’, JANET is one of the best placed networks to show the way ahead.
Recently there have been a number of stories in newspapers, on the TV and on radio asking essentially ‘is the Internet running out of addresses?’ For a lot of users the answer is ‘yes’ – but only because they continue to use IPv4, the version of IP first deployed back in the 1970s. For organisations willing to update to IPv6 the Internet is in no danger of running out of addresses at all.
What is happening
The Internet Assigned Numbers Authority (IANA), which is responsible for the global coordination of Internet addresses, distributes ranges of addresses to Regional Internet Registries (RIRs). On 3 February 2011 IANA allocated the final five ranges, each equivalent to 1/256 of the entire address space, to the RIRs. In other words, IANA has no more addresses available to allocate.
This event was anticipated well in advance. Most of the Internet currently runs under IPv4. The 32-bit address space used by IPv4 allows a theoretical 4 billion devices to connect to the Internet. Although that is a very large number, it is still a finite resource and it has always been accepted that it will one day run out. The process has been hastened in recent years as more and more mobile devices connect to the network – something not widely expected to happen 30 years ago.
The Internet Engineering Task Force (IETF) has been developing IPv6, the successor to IPv4, since 1996. IPv6 allows a vastly increased address space, offering 128-bit addresses in place of IPv4’s 32-bit addresses. JANET began to support early IPv6 trials in 1998, and while currently only a handful of UK ISPs offer IPv6 to their customers, JANET has the biggest UK production deployment.
What happens now?
In the short run, many universities are lucky enough to have large assignments of IPv4 space from systems that pre-dated the RIRs. They may be able to continue to grow and provide new services using this space. Many smaller institutions use Network Address Translation (NAT), which requires only a small number of addresses and which some find more secure: it also serves as a workaround letting hosts running IPv6 communicate with hosts that run IPv4, and this makes them largely independent of the requirements for public addresses. However, services that are available to other sites and data-centres hosted off-site require public addresses to be reachable. Even with NAT, sites may find a gap between the last IPv4 address being handed out and their ability to deploy IPv6 ubiquitously.
RIRs will continue to assign their remaining resources until they each only have a single range of address space remaining. At that point other policies come into effect, and Local Internet Registries (LIRs) such as JANET(UK) will only be able to receive one more small block of IPv4 address space. JANET(UK) will continue to allocate from the address space it has received from the European RIR, RIPE, until that is exhausted. At the moment we are using that at a relatively slow pace due to the widespread use of NAT among the community. The special policies in place for the last range should help to ensure that new services deployed on the Internet can continue to receive IPv4 addresses.
In the longer term, we continue to advise all of our customers to investigate IPv6 and devise a deployment plan as soon as possible. There are short-term alternatives and fixes but a commitment to IPv6 is the only long-term solution for IPv4 exhaustion and for meeting the massively expanded demand for addresses.
JANET provides a range of support for organisations wishing to implement IPv6. Technical guides for IPv6 (recently updated) and IPv6 Multicast (PDF or epub) are available, as is a summary for network managers and a list of links to other useful resources.
There may still be some time before IPv6 is as widely adopted as is needs to be, both within JANET and the wider community. A few thoughts on that, and an invitation to participate in some discussion, are in JANET’s Development Eye blog.
- JANET(UK)’s IPv6 page: www.ja.net/development/network-engineering/ipv6/
