Aeronautical Telecommunications Network
The Aeronautical Telecommunications Network (ATN) is a data communication network defined by the ICAO based on Open Systems Interconnection (OSI) .
The intention of the ICAO in defining the ATN is to use a common network for different air traffic control applications. It must be taken into account that ATN not only has to support the data exchange of ground-based systems (compare fixed aeronautical radio service ), the so-called ground-ground communication , but also the data exchange between aircraft and ground systems ( air-ground communication ). Important applications of ATN today are AMHS and CPDLC.
AMHS ( ATS Message Handling System ) serves to replace the Aeronautical Fixed Telecommunication Network (AFTN), which is used for the worldwide exchange of flight plan data. In order to support the technology change from AFTN to AMHS, gateways are required between the newly emerging AMHS network and the existing AFTN.
CPDLC ( Controller-Pilot Data-Link Communications ) enables the exchange of text-based messages between air traffic controllers and pilots with the intention of replacing the verbal communication via radio that is common today.
Due to the costly and complex routing technology of OSI, a large number of users of the ATN use TCP / IP for ground-based data exchange . For the global AMHS this has the consequence that corresponding node computers take over the data transfer as a transition between the OSI and TCP / IP networks.