A common carrier is a private telecommunications entity operating under regulatory authority to provide transmission services to the general public. By law, they must offer their services at transparent, tariffed rates and cannot refuse service to a paying customer or censor the data flowing across their lines. This legal status protects the carrier from liability for the content transmitted by its users.
Since they operate as a common carrier, they have to lease that dark fiber at the tariffed rate.
Related terms
CLEC
A competitive local exchange carrier is a telecom provider competing with the established regional telephone company.
ILEC
The established regional telephone company that owned the original copper wire monopoly before market deregulation.
LEC
A regulatory term for a local telephone company that provides service within a specific geographic area.