North America is forecasted to run out of IPv4 addresses this summer. The American Registry for Internet Numbers (ARIN) notes that only 3.4 million of the 1.3 billion IP addresses assigned to the region remain available. Fortunately, there’s already a backup plan in place but it won’t exactly be cheap to make the switch.

As The Wall Street Journal reminds us, those who created the Internet in the early 1980s created a finite amount of addresses – roughly 4.3 billion – as part of the IPv4 specification. While that may have seemed like a huge number back then, today’s Internet-driven world is proving otherwise.

Running out of addresses won’t spell the end of the Internet but it’ll certainly be a hassle, especially for large companies like those that provide cloud computing services. The Journal points out that unprepared companies could incur unexpected costs, technical issues or even the inability to take on new customers.

Large companies like Amazon, Salesforce and Microsoft have been snapping up IPv4 addresses by the hundreds of thousands, paying on average $11.25 per address. Others, like Facebook, have already made the switch to IPv6.

Approved in 1998, IPv6 is the most recent version of the Internet Protocol. Whereas IPv4 uses 32-bit addresses to provide a maximum of 4.3 billion addresses, IPv6 addresses are 128 bits long which increase the number of available addresses to 340 undecillion (that’s the number 340 followed by 36 zeroes – enough to supply every atom on Earth with its own IP address).