50 Billion Devices On A 4 Billion Device Network

For most users of the Internet, it appears to them simply as a series of apps and browser windows, instead of a global computer network it is a range of services such as Facebook or Google that they use for information or entertainment. They may be dimly aware from TV investigative dramas such as NCIS that each device using the Internet has some kind of address, but beyond that the only addresses they know about are domain name addresses such as ebay.com or digid.nl. Slightly more technically inclined home users will have opened up their router configuration or used an online broadband speed checking tool, and thus encountered IP addresses. These 4-number addresses that correspond to four bytes of computer memory are referred to as Internet Protocol version 4 or IPv4 addresses, and give a possible range of over 4 billion computers that can be connected to the Internet.

A Network For A Simpler Time

Four billion connections to the Internet sounds impressive, but it brings with it a problem that didn’t exist back when the only devices with internet connections that most people owned were a desktop computer and just maybe a smartphone. When the cartoonist Randall Munroe mapped the entire Internet back in 2006 his map contained plenty of green space signifying as-yet-unused IP addresses, but by contrast the same map computed by USC’s ANT Internet Census shows the 2020s IPv4 Internet to be a much more congested place. It is estimated that there are now as many as 50 billion devices connected to the Internet with many more due to join them as the huge expansion of IoT technology continues, and even with the use of address-sharing techniques such as Network Address Translation or NAT it’s clear that the available pool of addresses is nearly exhausted.

Happily there has been a solution to IPv4 address space congestion since the mid 1990s, in the form of Internet Protocol version 6, or IPv6. This replaces the four bytes of 32-bit IPv4 addresses with 16 byte 128-bit addresses allowing for up to 2128 possibilities. That’s a number which goes beyond the everyday language of numbers and leaves mere millions and billions far behind, but written down in decimal it comes to 340,282,366,920,938,463,463,374,607,431,768,211,456. It’s designed such that no address sharing is required and every device can have a unique address, and barring the unthinkable it should have enough capacity to accommodate even the largest estimates of future Internet expansion. As a bonus it’s also designed for much more efficient routing than IPv4, allowing for faster transit of multi-point connections over the Internet.

It would be tempting to think therefore that with IPv6 having existed for a quarter century, the Internet’s problems would be over. Sadly the truth is not so appealing, as despite decades of warnings about IPv4 congestion the process of making the transition remains a stubbornly slow one. RIPE, the body that supports the IP networking in Europe and east Asia, publish statistics for IPv6 take-up, and their graph shows it to still be below 30% globally. The Netherlands bucks the trend at above 50%, but it’s still clear that the remaining IPv4 networks are rapidly approaching address saturation.

It’s worth asking the question then, where are these IPv4 networks and why have they not made the switch? In some cases the answer is pretty simple, despite commercial network hardware supporting the new protocol for many years there may still be an installed base of older routers that only support IPv4. In particular there are domestic ISPs supplying connectivity to home users which may have tens or hundreds of thousands of installed home routers, and the commercial pressure for replacing them while they still work is evidently not yet strong enough.

Moving To A Less Congested Future

As a hosting company, ProcoliX has fully embraced IPv6-based infrastructure so is already future-proof. We still run an IPv4 network for some legacy customers who depend upon it, but the future is clear. Here in the Netherlands we have a higher-than-average IPv6 roll-out driven by the move to fibre-connections, and as this continues there is increasingly no case for any Internet-based business to remain on a network running the older protocol.

Moving to IPv6 does not have to mean abandoning end users still on IPv4 connections though. The sheer number of addresses and the IPv6 philosophy of every device having its own real address without any need for NAT means that while IPv4 and IPv6 are not interoperable the entire IPv4 address space can be mapped virtually by a router as a subnet of a 12-byte IPv6 range. Thus IPv4 traffic can be served from an IPv6 network, and ProcoliX-hosted sites can continue to deliver a high-performance service to customers on IPv4 networks.

You might ask, whether an Internet divided between the two protocols is such a bad thing. After all since they have been existing side-by-side for so long could that not simply continue forever? The answer is that a two-tier network of faster IPv6 alongside a congested and slower IPv4 range held together by compromises to manage a lack of addresses and a need for tunnelling IPv6 traffic across it will become increasingly impractical. Eventually new devices will deprecate IPv4 support, and those ISPs who still rely on it will be forced to update their installed router base in response to customer demand. Those new routers will probably incorporate IPv4 to IPv6 mapping to support legacy smart devices, and eventually a point at which that RIPE graph reaches 100% will be reached. We can’t yet say when that will finally happen, but we are guessing that progress in the further reaches of the Internet will for now be slow.

It’s evident that time is running out for the IPv4 Internet, and that customers of ISPs who have resisted an upgrade will find themselves in the second tier. ProcoliX is an IPv6 hosting provider, are you ready to join us?

Header image: Kim Scarborough, CC BY-SA 2.0.