Home Internet service provider Comcast says that the company will implement "usage-based billing" by 2019, which suggests that customers will get specific data allotment on a monthly basis and may be charged if they go beyond the allotment.

At a recent investors call David Cohen, Comcast's Executive VP said that in the next five years, he thinks that the company will implement "usage-based billing model rolled out across its footprint." He hinted that in the next five years, a data cap of 500 GB may be optimal for most customers.

"I would also predict that the vast majority of our customers would never be caught in the buying the additional buckets of usage, that we will always want to say the basic level of usage at a sufficiently high level that the vast majority of our customers are not implicated by the usage-based billing plan," says Cohen. "And that number may be 350-that may be 350 gig a month today, it might be 500 gig a month in five years."

"I don't think that's the model that we are heading toward but five years ago I don't know that I would have heard of something called an iPad. So very difficult to make predictions," added Cohen.

Comcast has millions of customers using its services in the U.S. The company has already rolled out data caps as a trial in select regions it serves. The current data cap in some of these areas is 300 GB per month while in others it is 600 GB per month. After crossing the data limit, a customer has to pay $10 for every extra 50 GB of usage. Customers can exceed the data allowance for three months out of 12 months and will not have to pay any extra charge.

Comcast is in talks for a $45 billion deal with Time Warner Cable (TWC) and the merger is expected to go ahead towards the end of 2014. TWC also offers a 30 GB Internet data plan to its customers, but awards customers with a monthly credit if they stay under the data cap. Cohen added that the company's plans to implement usage-based billing should not affect the TWC deal.