Rural Americans have experienced telephone calls not going through and sub-par quality due to entities known as "least cost routers" .
Least cost routers are entities hired through a long-distance carrier at an attempt to minimize costs by failing to deliver calls to rural areas where the cost to provide service is higher. 
Consumers are generally unaware the routers exist and both the carries involved and the FCC have trouble identifying all of the least cost routers handling the calls.

To see how congress is addressing the issue Read the full story here on NTCA's website.