AFDX stands for Avionics Full-Duplex Switches Ethernet. This is an Airbus-patented technology data network used in avionics. The system combines Ethernet with ATM (asynchronous transfer mode) technology to provide reliable bandwidth. AFDX’s Quality of Service (QoS) is able to prioritize critical and non-critical messages to avoid collisions of transmitted data.
Uses
AFDX is of course used on Airbus products, but it is also used on the Boeing Dreamliner and Super Jet as well as many others. AFDX is an essential key to many operations including in-air power, landing gear and flight controls. It is also used in aircraft tests and simulations. The system works by connecting each module (or subsystem) to the overall network so they can communicate.
Features
One of the main considerations in the AFDX network is the Bandwidth Allocation Gap (BAG). This is a fancy term for the maximum rate at which data can be transmitted in order to guarantee its delivery. This rate has also to allow for other virtual links to be sent as well without exceeding 100Mbit/s. In other words, the BAG is shared with numerous virtual links so it must have space for all of them to be sent at the same potential time.
Reliability is achieved by sending the same message through two connections at the same time. If one message is transmitted improperly, the erroneous line is excluded, and only the correct message is sent. If both messages are acceptable, one is still excluded and only one sent to avoid confusion. This automatic back-up system ensures that all messages are received accurately, every time.
Benefits
The AFDX network is much faster than the most popular system before it. It uses fiber-optic connectors (while the previous system used copper) for transmitting data. In addition to its speed, this system is extremely reliable. Another benefit is that AFDX parts are standard, so replacements are easy to come by and easy to install. This eliminates any chance of delays due to upgrades, repairs or replacements.
Not only are the parts easy to obtain, but they are also cost-effective, space-efficient and lightweight. In other words, there are fewer wires to connect, maintain and store out-of-sight and the system adds less overall weight to the aircraft. These are huge benefits to the avionics industry.
