The aeronautical industry has recognized the need to apply standard communications protocols and services using the OSI Reference Model. The aeronautical industry has chosen to implement standard protocols within their data communications systems, as appropriate, and to use products and services which have already been developed in accordance with appropriate existing, internationally-accepted, data-communications standards.

The aeronautical industry also recognizes that certain applications that utilize data communications do not have well defined nor widely used solutions within the strict context of the OSI Reference Model. Often they have no solution at all using the OSI standard protocols. The aeronautical industry has, therefore, decided not to limit the middle and upper layer protocols associated with this Specification to those conforming to the OSI protocol suite as defined by ISO.

The OSI Reference Model was developed to provide a common basis for the coordination of standards development for the purpose of integrating data communications systems. The OSI Reference Model itself does not achieve the goal of interoperability; however, it does serve as the catalyst to enable independent development of standard protocols that ultimately achieve the goal of interoperability within the selected protocol stack (for example, OSI, TCP/IP, or others). Part 2 is based on IEEE Standard 802.3, 2005 Edition.

Purpose of Document

The purpose of this document is to define Ethernet physical parameters and data link layer specifications for use in a commercial aircraft environment. It provides general and specific guidelines for the use of IEEE 802.3 compliant Ethernet. Physical Layer and Medium Access Control sublayers are expected to comply with the Open System Interconnection (OSI) Reference Model.

It is the intention of this document to deviate as little as possible from the existing applicable IEEE and ISO standards, thereby enabling maximal utilization of offthe- shelf components, both hardware and software, for aviation use. Part 1 of ARINC Specification 664 provides an overview of an Ethernet data network. This document, Part 2, is the second part of a multi-part standard.