ISP Column - January 2025
Time for another annual roundup from the world of IP addresses. Let’s see what has changed in the past 12 months in addressing the Internet and look at how IP address allocation information can inform us of the changing nature of the network itself.
Back around 1992 the IETF gazed into their crystal ball and tried to understand how the Internet was going to evolve and what demands that would place on the addressing system as part of the “IP Next Generation” study. The staggeringly large numbers of connected devices that we see today were certainly within the range predicted by that exercise. Doubtless, these device numbers will continue to grow. We continue to increase silicon chip production volumes and at the same time we continue to refine the production process. But, at that time, we also predicted that the only way we could make the Internet work across such a massive pool of connected devices was to deploy a new IP protocol that came with a massively larger address space. It was from that reasoning that IPv6 was designed, as this world of abundant silicon processors was the issue that IPv6 was primarily intended to solve. The copious volumes of address space were intended to allow us to uniquely assign a public IPv6 address to every such device, no matter how small, or in whatever volume they might be deployed.
But while the Internet has grown at such amazing speed, the deployment of IPv6 continues at a more measured pace. There is still no evidence of any common sense of urgency about the deployment of this protocol, and still there is no common agreement that the continued reliance on IPv4 is failing us. Much of the reason for this apparent contradiction between the designed population of the IPv4 Internet and the actual device count, which is of course many times larger, is that the Internet rapidly changed from a peer-to-peer architecture to a client/server paradigm. Clients can initiate network transactions with servers but are incapable of initiating transactions with other clients. Network Address Translators (NATs) are a natural fit to this client/server model, where pools of clients share a smaller pool of public addresses, and only require the use of an address while they have an active session with a remote server. NATs are the reason why in excess of 30 billion connected devices can be squeezed into some 3 billion advertised IPv4 addresses. Applications that cannot work behind NATs are no longer useful in the context of the public Internet and no longer used as a result.
