scope:

Purpose: The intent of this document is to provide general and specific design guidance for the development and implementation of an On-board Local Area Network (OLAN) for use in an aeronautical Open Systems Interconnection (OSI) communications environment. Only the Physical Layer and Data Link Layer of the OSI Basic Reference Model (ISO 7498) are specified by this document. The network and upper layers are defined in ARINC Specifications 637 and 638 respectively. This Specification embraces internationally recognized standard protocols and provides a very high bandwidth digital data network to interconnect avionics systems. It is expected that other networks such as the Aeronautical Telecommunications Network (ATN) will use OLAN and thus, the use of standard protocols will simplify the interconnection to these other networks and minimize the use of gateways or other types of protocol converters.