AFDX

AFDX, or Avionics Full-Duplex Switched Ethernet, is a safety-critical avionics data network standard designed to provide deterministic, fault-tolerant communication in civil aircraft. It is based on Ethernet technology and implements ARINC 664 Part 7, a set of extensions that impose real-time guarantees suitable for airborne systems.

Architecturally, AFDX uses a pair of redundant, switched Ethernet networks—commonly referred to as primary and secondary fabrics—to form a fault-tolerant data path. Avionics equipment such as flight-control computers, sensors, and displays connect to the fabric through ARINC 664-7 switches. Data is transmitted in frames associated with Virtual Links (VLs); each VL has a defined maximum bandwidth and frame-generation rate to support predictable timing.

Determinism is achieved by traffic engineering and scheduling within the switches: VL-based bandwidth reservations, fixed frame intervals, and strict forwarding rules ensure bounded latency and jitter for critical messages. The architecture also provides redundant data paths and error-detection mechanisms, enabling failover and resilience in the event of a network fault. Standardized safety analyses support certified operation in airworthiness environments.

Usage and deployment are targeted at civil aviation, with the standard having been adopted in major airframes. It provides a scalable, Ethernet-based backbone for the distribution of avionics data while maintaining the deterministic behavior required by flight-critical systems. AFDX enables integration of diverse avionics subsystems—such as flight controls, navigation, and displays—on a common, real-time fabric, thereby improving reliability and maintainability in modern aircraft.