AT&T’s data cap has been in effect for a week and public interest groups are asking questions.

The company’s justification is easing the burden of its network. It said certain heavy users drain a disproportionately large amount of network resources at the expense of other users. Limiting these users, therefore, will make it fairer for everyone else and easier for AT&T.

Skeptics, however, question AT&T’s stated motives and wonder if they are ulterior motives.

A key concern is if AT&T is unfairly targeting high-data services like Netflix and Skype in an attempt to influence users to switch to AT&T products that offer similarly services.

Public Knowledge, a public interest group based in Washington, D.C., said the first question AT&T must answer to regulators is if certain AT&T services like voice telephony and video programming are excluded from the cap.

Below are 7 more questions Public Knowledge thinks AT&T must answer:

• How often the cap is enforced. This should include the absolute number of customers who exceed the cap as well as the percentage of customers who run afoul of the limit. Additionally, it should include amount by which the customers exceeded the cap and how many of those customers are repeat cap exceeders.

• Steps taken to warn customers. This should include the steps taken to warn customers, and when those steps are taken. Additionally, the reporting should include data on the effectiveness of these warnings in preventing overages.

• Average penalty incurred by customers. Caps such as AT&T’s charge additional fees based on how significantly the cap is exceeded. Reporting should include data on the size of the penalties incurred by customers.

• When and how often a penalty is waived. In addition to the publicly announced grace periods, the Bureau would be well served by understanding how often and under what circumstances reporting ISPs grant additional waivers.

• The relationship of enforcement to times of network congestion. If used properly, data caps can a tool in easing network congestion. However, there is a constant threat that ISPs use network congestion as a pretext to act on other motives. The Bureau would benefit from a nuanced understanding of the relationship between data cap enforcement and network congestion.

• How data caps are set. For example, why did AT&T choose 150GB for DSL and 250GB for U-Verse customers? What criteria are used to arrive at the cap? What criteria are used to determine appropriate overage fees?

• How data caps are evaluated on an ongoing basis. Data caps are often defended as necessary to address current network congestion issues. However, network technology is constantly being modernized and made more efficient. In light of this pattern of improvement, caps that are appropriate for today’s network may be inappropriate in the future. How do ISPs evaluate their existing caps, and what are the conditions under which those caps could be raised and/or eliminated?

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