If you’re like me, you turned the idea of Internet-connected household appliances – refrigerators with browsers and display screens, for example – into the butt of gentle jokes about 10 years. Suddenly, however, the idea of a fridge with a browser doesn’t seem so far-fetched. Networking giant Cisco (News - Alert) has predicted that the number of Web-connected devices will rise precipitously during the next four years to over 15 billion – twice the world’s population by 2015.

Cisco says the proliferation of tablets, mobile phones, connected appliances and other smart machines will drive this growth. The company said consumer video will continue to dominate internet traffic. It predicts that by 2015, one million minutes of video will be watched online every second, reported BBC news.

The predictions come from Cisco’s fifth annual forecast of upcoming trends.

Cisco’s Visual Networking Index also estimated that at the same time more than 40 percent of the world’s projected population will be online, a total of nearly three billion people.

The networking giant forecast that by 2015 internet traffic will reach 966 exabytes a year (an exabyte is equal to one quintillion bytes.) In 2004, global monthly internet traffic passed one exabyte for the first time.

But Cisco said alongside this quadrupling of traffic comes a number of very real concerns.

“What you are seeing is this massive growth in devices, the way devices are being used and are connected to the internet and what users expect them to do,” said Suraj Shetty (News - Alert), Cisco vice president for global marketing. “All this is putting a lot of pressure on the internet and the next generation internet faces issues handling not just the proliferation of these devices but how they are going to grow and be intelligent enough to be connected to you.”

“The most important question we face is how to manage all this traffic intelligently,” Shetty added.

It’s a very real problem. Cisco’s report underlines a very real problem the internet as a whole faces as it runs out of what is known as internet protocol version 4 or IPv4 addresses. Every Internet-connected device needs one of these IPv4 addresses to send and receive data online.

When IPv4 was created in 1977, it was thought that its pool of 4.3 billion addresses would be enough for the future.The rise in the number of mobile devices, laptops and connected machines has helped exhaust that stock.

In February, the Internet Assigned Numbers Authority handed out the last batch of these addresses. Industry experts believe they could be all used up as early as August.

The solution is an alternative addressing standard approved in 1998 called Ipv6. There are trillions of these addresses but persuading companies to move to IPv6 has been a slow process.

“We are running out of IPv4 addresses and the adoption of IPv6 is going to be front and center of everything for the next several years,” Shetty told BBC News.

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