Networking concepts comparison for avionics architecture (2008)

The purpose of this paper is to evaluate alternative networking concepts (standards and protocols), with a particular emphasis on comparing ARINC 664 network standard with legacy avionics networks. The conclusions of this comparison are reinforced with an example network solution for the avionics architecture using the Avionics Full- Duplex Switched Ethernet (AFDX) protocol. The networking of modules (hardware and software) and applications on an aircraft is crucial, and often new designs and upgrades rely on legacy network architectures. In the past, such systems in defense applications have been successfully integrated around the 1553B bus architecture, while commercial applications have satisfied FAA requirements with systems integrated around the ARINC 429 bus architecture. The new applications and capabilities being requested by stakeholders for Avionics systems of the future require increased bandwidth and latency requirements that suggest likely inadequacies in legacy bus architectures. There is continuing pressure by pilots for more information displayed on increasingly more intuitive graphical displays and interfaces; while the ground control and logistics teams want additional and more timely airplane status data - this data is consolidated from a multitude of sub-systems and sensors on board, including event logs and trend data. These new demands may require us to leverage new technologies to keep pace with stakeholder expectations today and in the future. A recent advancement in networking technology is ARINC 664, which defines a deterministic version of an Ethernet network. Boeing and Airbus have adopted Avionic Full- Duplex Switched Ethernet for their newer airplanes [1-3], and NASA is considering ARINC 664 for the new Crew Exploration Vehicle [4]. The B787 is slated to accommodate 100 applications in part due to the availability of larger network bandwidth [5]. NASA hopes to benefit from commercial-off-the-shelf (COTS) Ethernet components which include reduced overall costs, faster system development and less-costly maintenance for the system network. Both found ARINC 664 to be the best fit in ARINC 653 based systems. Integrating an Avionics Full-Duplex Switched Ethernet may benefit the defense industry avionics customer by lowering life cycle cost and accommodating increasing requirements. This paper addresses the speed, reliability, and flexibility of modern network protocols and explores new options for avionics architectures. This applies to either a complete redesign or a phased avionics upgrade in legacy airplanes. For a historical context, this paper also summarizes the value and utility of legacy networking protocols, together with their downsides. Networking standards and protocols are evaluated as a function of critical requirements pertaining to performance, certification, security, reliability, evolvability, cost, and flexibility to meet changing requirements. Methods such as Quality Function Deployment (QFD) and Analytic Hierarchy Process (AHP) are used to evaluate the three network architectures. The impacts on security and reliability are explored, and additional aspects are highlighted for future research.