ARINC Specification 631-7:2017

This document describes the functions to be performed by airborne and ground components of the VDLM2 to successfully transfer messages from VHF ground networks to avionics systems on aircraft and vice versa where the data are encoded in a code and byte independent format. The compatibility of VDLM2 with OSI is established by defining a set of services and protocols that are in accordance with the OSI basic reference model. The compatibility with the ATN protocols is achieved by defining a set of interfaces between the VDLM2 subnetwork protocol specification and the Mobile Subnetwork Dependent Convergence Function (MSNDCF). The SNDCF is defined in the ICAO ATN SARPs.