Let's set the record straight on what "Unlimited" really is. 

Although the carriers do not provide hard data caps or limits of potential usage in the description of the plans they provide, algorithms monitor the networks constantly for traffic and congestion issues. 4G LTE data plans are provisioned on a shared network and the carriers guard against any one user detrimentally impacting other users. The carriers will act to control this detrimental impact by slowing speeds, restricting use, and worst case, canceling service without warning or notice as they see fit.

Unlimited does not mean unlimited data at unlimited speeds. Nor does it include super-heavy usage (e.g. uploading or downloading games, game updates, or large files in a short time period). These plans typically provide a reasonable amount of data usage in a steady, moderate usage pattern.

Carriers continuously monitor their networks for “spikes” in data usage which they may see this as a malicious attack on their network. As a result, carriers seek to mitigate such “attacks” by limiting traffic identified as potentially harmful and therefore degrading to the quality of their service (see de-prioritization). To avoid this situation, we recommend to always use data wisely and treat it like a utility opposed to a cable subscription in which you can watch tv 24/7 with no affect on your service or monthly bill. Moderate, steady usage is best. 

Disclaimer: All AT&T based plans are subject to AT&T's Acceptable use policy which means we do not have any control on your plan aside from the prepayment of non-refundable service on your plan each month. If AT&T detects abnormal or abusive usage of their network, they can and more than likely will terminate your service line (sim card) without notice or refund to us (you).