IPv4 vs IPv6: when will the internet's latest protocol finally take over?

IPv4 exhaustion has been a recognised issue for a long time, although adoption of the next generation of the Internet Protocol has remained sluggish. We look at why this has been the case and whether IPv4 is set to fade away any time soon.

The massive, far-reaching, and rapid growth of the internet internationally has undeniably spurred a great deal of innovation and afforded both businesses and individuals a wealth of benefits and convenience. However, as the internet grows and becomes more engrained in people's lives and the day to day operations of organisations from almost every industry, a fundamental and increasingly significant issue has risen to the fore around the sheer number of internet facing devices that are being employed on a wide-scale (particularly those at the network's edge).

This issue, as you may have guessed from the headline, is around the structural limitations of IPv4, the most prevalent generation of the Internet Protocol (of IP address fame) that is essential for routing traffic on the internet. Principally, IPv4 is limited in that there aren't enough IP addresses within the protocol to go around, with the total number of IPv4 addresses now finally reaching a point of actual depletion.

While the logical resolution to this issue - to upgrade from IPv4 to the much more future proof next generation of the protocol IPv6 - has been recognised for quite some time, things aren't as easy as they seem. There are a range of issues standing in the way of IPv6 uptake that continue to hold relevance since it was first introduced in the late 90s. As a result, it's still not exactly clear when IPv6 is actually going to go ‘mainstream', and whether IPv4 will ever really die out.


The problem with IPv4

Despite being first introduced in the early 1980s, Internet Protocol Version 4 is still the most widely used version of IP on the internet today. Using IP addresses (that look something like, the protocol is used to identify any particular piece of hardware on the internet and is fundamental for routing traffic and thus the function of the internet itself. As a 32-bit protocol, IPv4 contains 232, or 4.29 billion possible IP addresses. While, at the time it was first conceived, this was considered to be more than enough IP capacity, as billions more devices hit the internet, IPv4 is hitting its absolute limits.

While IPv4 ‘exhaustion' has been talked about for years, the problem has become increasingly concerning as the five international bodies responsible for allocating IPv4 addresses, known as Regional Internet Registries (RIRs), have literally ran out of new IPv4 batches. The latest in this saga came in November last year, when the European RIR, RIPE NCC, announced that it had made its final /22 IPv4 allocation and had thus run out of IPv4 addresses. While the registry will continue assigning IPv4 addresses as businesses close or as networks return addresses they no longer need, RIPE NCC noted that these small allocations, "will not come close to the many millions of addresses that networks in our region need today."

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