This specification applies to avionics data networks used aboard commercial aircraft. It provides a means to adapt Internet and IEEE data networking standards. It provides standards that are intended to enable interoperability among and between avionics networks. The same standards are intended to enable interoperation of avionics end systems that use those networks.

The Aircraft Control and Airline Information Services Domains can be subdivided into sub-domains. The Aircraft Control Domain can be broken down into a Flight and Embedded Control System sub-domain where the aircraft is controlled from the flight-deck and a Cabin Core sub-domain that provides environmental control of the aircraft from the cabin. The Airline Information Services Domain is subdivided into a sub-domain that provides operational and airline administrative information to both the flight deck and cabin, and a sub-domain that provides information that provides support for the passengers. The Passenger Information and Entertainment Services (PIES) domain is usually provided by a single supplier and is decomposed in Section 2.2, Aircraft Domains and Related Concepts.

A set of data network terms is essential to the understanding of data networks and to characterizing their performance. These terms are defined relative to data networks, where multiple nodes send messages to each other and receive messages from each other. For example, switches, routers, and bridges may be part of the network, but the data network terms are defined with respect to the nodes that source and sink messages. A message, as used in data networks, is the indivisible element of data sent from one node to another. In an Ethernet network, a message is an Ethernet frame. Appendix A is a tutorial of data networking.

Purpose of this Document

ARINC Specification 664 has been developed in several parts and written with a view that commercially available Commercial Information Technology Standards can be applied to aviation with minimal changes. Further, where there are selections among the commercial standards or deviations for aviation requirements, there is provision to record and disclose those selections and deviations in the form of Protocol Implementation Conformance Statements (PICS) and Services Implementation Conformance Statements (SICS), PICS SICS increases interoperability, broadens supplier availability, and ultimately, reduces cost.

Going forward with ARINC Specification 664 has required the refinement of the original guiding principals of translating commercial IP protocols and services to better describe where ARINC Specification 664 fits within the other ARINC standards. ARINC Specification 664 is not expected to be used on existing data links. It is expected to be used on new links.

Conceptually, ARINC Specification 664 is a transport standard. As a transport standard, protocols, services, data flows and data structures are defined. To use the ARINC Specification 664 data channel then imposes certain common requirements on the end systems. The value of these requirements to the end systems is a reduced complexity of transport and an increased interoperability with other end systems.

The use of commercial standards reduces the need for aviation-specific interface specifications when the commercial standards meet the aviation requirements. To gain the benefits of the commercial standards, ARINC Specification 664 is based upon standard Internet protocols and services and selection of options from commercial standards as well as deviations from the commercial standards that are documented in PICS and SICS.

In addition, this supplement has refined the original view of the aircraft domains. Figure 1.1 of Part 1 is supplemented by Figure 1.1 that follows.

The purpose of this document is to provide an overview of data networking standards recommended for use in commercial aircraft installations. These standards provide a means to adapt commercially defined networking standards to an aircraft environment. It refers to devices such as bridges, switches, routers and hubs and their use in an aircraft environment. This equipment, when installed in a network topology, can optimize data transfer and overall avionics performance. This specification refers extensively to the set of data networking standards developed by the Internet community and IEEE. This specification recognizes Open Systems Interconnection (OSI) standards.

This document provides:

• Background of aircraft data network standards.

• Guidance for Compliant Networks, Profiled Networks, and their interfaces.

• Tutorial for the adaptation of commercial network standards to commercial aircraft.

• Terminology for aircraft data networking.

As described in Section 1.3, this specification is comprised of parts. For those knowledgeable in avionics data networking and networking standards in general, it is appropriate to go directly to the part of this specification of immediate interest. For those who would like to learn more about networking, this document provides tutorial and background material. However, it is beyond the scope of this document to provide all information necessary to completely describe how networks should be implemented. This specification builds on commonly understood data networking concepts. Readers who desire additional information should refer to widely published textbooks and other material on the subject of data networking.