Bridging Legacy Avionics Data Busses to Ethernet Based Networks

Abstract

Ethernet is becoming more widely used as the network backbone in Integrated Modular Avionics (IMA) architectures. The advantages provided by Ethernet solutions include higher data throughput rates, ubiquitous use, lower costs, and high availability of components. Because of these advantages, new aircraft system designs and technology updates to existing system designs are considering Ethernet to replace legacy data bus technologies including MIL-STD-1553, ARINC-429, and CANbus based networks. Despite the advantages of Ethernet over these legacy technologies, latencies in standard IEEE 802.3 Ethernet networks is unpredictable. Defining when a data packet leaves a node and is received by another in absolute terms, and guaranteeing that the data will be received at its intended destination cannot be accurately predicted or guaranteed. Enhancements to IEEE 802.3 such as ARINC-664, and AS6802 enable determinism and guaranteed quality of service that the legacy data bus technologies provided. This paper provides an overview of deterministic Ethernet technologies such as ARINC-664 and AS6802 (TTEthernet) that define deterministic, guaranteed quality of service networks. It also considers the advantages, disadvantages, and possible applications utilizing bridges between MIL-STD-1553 data busses and these Ethernet protocols and considers other related protocols such as IRIG 106 Chapter 10.