In February 2011, the global Internet Assigned Numbers Authority (IANA) allocated the last blocks of IPv4 address space to the five regional Internet registries. At the time, experts warned that within months all available IPv4 addresses in the world would be distributed to ISPs.
Soon after that, unless everyone upgraded to IPv6, the world would be facing a crisis that would hamper Internet connectivity for everyone. That crisis would be exacerbated by the skyrocketing demand for IP addresses due to a variety of factors: the Internet of Things (refrigerators needing their own IP address); wearables (watches and glasses demanding connectivity); BYOD (the explosion of mobile devices allowed to connect to the corporate network); and the increase in smartphone use in developing countries.
So, here we are three years later and the American Registry for Internet Numbers (ARIN) is still doling out IPv4 addresses in the United States and Canada.
Whatever happened to the IPv4 address crisis?
The day of reckoning still looms — it's just been pushed out as the major Internet players have developed ingenious ways to stretch those available numbers. But these conservation efforts can only work for so long.
ARIN currently has "approximately 24 million IPv4 addresses in the available pool for the region," according to President and CEO John Curran. They're available to ISPs large and small, but Curran predicts they will all likely be handed out by "sometime in 2014."
Even then, addresses will still be available to be assigned to the operators' clients for a while longer. And not all operators are likely to experience shortages at the same time. "It's more of a problem for networks that are growing. For networks that are stable, they can reuse addresses" as some customers drop their service and new ones sign up.
Phil Roberts, technology program manager for the Internet Society, adds, "There's some anticipation in using addresses. Network operators get a block and parcel them out — you don't get them right when you need them."
How did we get here?
The problem took no one by surprise. The Internet Engineering Task Force (IETF) foresaw the global growth of network-connected devices 20 years ago, and in response drafted a new version of the Internet Protocol to address the looming shortage.
IPv6 uses a 128-bit address space — that is, 2^128 — yielding far more potential addresses than IPv4's 32-bit scheme, and in fact more addresses than there are grains of sand in the Earth's crust.
So, why hasn't everyone just switched over to IPv6?
Well, IPv6 is not backward compatible with IPv4, meaning network operators need to run a dual stack IPv4/IPv6 network for years to come. And for IPv6 to work, it needs to be implemented end to end, meaning IPv6 has to be enabled by network hardware vendors, transit providers, access providers, content providers, and endpoint hardware makers.
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