AT&T has told the Federal Communications Commission that it's going to conduct a little experiment (PDF) out west. Starting in this month, some of its customers in Reno, Nevada will be informed that their broadband will be "subject to a certain monthly usage tier for the total amount of data they may send and receive, as well as a per gigabyte charge in the event they exceed the usage tier."

How will these lucky test consumers know when they have reached this threshold? Two AT&T representatives outlined the plan in a meeting held on October 30 with a legal adviser to FCC Chair Kevin Martin. Customers will be equipped with an "online usage metering tool that displays a running total of the amount of data the customer has transmitted during a given month," the reps explained. If they reach 80 percent of their quota, Reno's broadband borderliners will get a notice from AT&T about the usage tier and the charges incurred if they exceed it.

AT&T is apparently taking a page from Comcast's book. At the beginning of October, the US' largest ISP instituted a 250GB monthly bandwidth limit for its customers. Why is AT&T experimenting with usage limits? "A small minority of our broadband Internet access customers consume a disproportionately large amount of the total bandwidth available to all of the customers on our network," AT&T explained. So something has to be done "to equitably provide affordable broadband services to all of our customers." An AT&T spokesperson told Ars that as few as five percent of all customers account for almost half of the total bandwidth consumed.

Being the nice company that AT&T is, however, the first time that a Reno resident goes over the line, they won't get dinged, financially speaking. "Only after the second time the customer exceeds the applicable monthly usage tier will the customer be subject to additional per-gigabyte charges," the telco explained to the FCC.

And in the spirit of choice, the ISP giant is making the usage tier experience optional, if you call having to quit the service an option. "In the event a new or existing customer does not want to participate in the trial, we will permit the customer to cancel their broadband Internet access service without an early termination penalty."

Most AT&T customers are on month-to-month plans without early termination fees anyway, the filing says. This provision would mostly apply to customers on term plans who decide that they don't want to be a member of the brave new usage tier vanguard. If they recently signed a new contract, they've got 30 days to get out.

Slowly but surely AT&T is making it clear to its broadband customers that they now live in an Age of Limits. In early September, the company informed the FCC that U-Verse buyers would soon receive new Terms of Service indicating that, in pursuit of optimal video performance, their high speed Internet throughput rates "may be temporarily reduced when a customer is using other U-verse services in a manner that requires high bandwidth."

This might take place with "higher speed Internet access products," the new language will disclose. Thus: "It may be necessary, for some AT&T High Speed Internet users, for AT&T to set a maximum downstream speed on a customer line to enhance the reliability and consistency of performance." Capacity speed, however, will never drop below the tier level that the customer has purchased.