The Inter-Area Traffic Network, or simply IATN, is an established system of traffic schedules descended from the much admired Transcontinental Corps or TCC.
Nets employ a group of highly skilled “ironman” operators who meet to relay messages between areas. Communications circuits are typically high-speed radiotelegraph or part of the DTN.
In many ways, IATN circuits are throwbacks to the trunkline system predating NTS’s formation in the 1950s. Here are two RRI white papers considering a contemporary implementation of trunklines