Introduction. “Avionic Full-Duplex Switched Ethernet” (AFDX), designated. ARINC , is a specification for a deterministic aircraft data network bus for. The latest ARINC data bus specification is known as ARINC This bus standard is based on an Airbus Industries proprietary data bus known as AFDX. The ARINC message format is based on the standard Ethernet frame. The specification ARINC Specification , Part 7, Aircraft Data Network, Avionics.

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This makes them more bandwidth efficient and more widely used. Archived copy as title All Wikipedia articles needing clarification Wikipedia articles needing clarification from September Additionally, there can be sub-virtual links sub-VLs that are designed to carry less critical data. AFDX was developed by Airbus Industries for the A, [3] initially to address real-time issues for flight-by-wire system development.

Office for Harmonization in the Internal Market. From Wikipedia, the free encyclopedia. There are two speeds of transmission: Retrieved May 28, Ethernet family of local area network technologies. There is no specified limit to the zpecification of virtual links that can be handled by each end system, although this will be determined by the BAG rates and maximum frame size specified for each VL versus the Ethernet data rate. AFDX is a worldwide registered trademark by Airbus. This frame differs from the Ethernet standard frame only by the addition of a Sequence Number field at speciication end of the frame.

MX Foundation 4: ARINC Frames

Contains the destination End System Identification. Also contains fragmentation information if a large message is being split into multiple frames. Implicit messages do not. Explicit messages contain format data to allow the receiver to interpret the data types.

AgustaWestland asserts its independence in the cockpit”. AFDX was designed as the next-generation aircraft data network.

A data word consists of 32 bits communicated over a twisted pair cable using the bipolar return-to-zero modulation. Contains specificatioj preamble, destination address, and source address.


Avionics Full-Duplex Switched Ethernet

This ADN operates without the use of a bus controller thereby increasing the reliability of the network architecture. Archived from the original PDF on A limited number of data types are defined for specificaiton messages and are listed below.

Avionics Full-Duplex Switched Ethernet AFDX is a data network, patented by international aircraft manufacturer Airbus[1] for safety-critical applications that utilizes dedicated bandwidth while providing deterministic quality of service QoS.

Basing on standards from the IEEE Further a redundant pair of networks is used to improve the system integrity although a virtual link may be configured to use one or the other network only. By using this site, you agree to the Terms of Use and Privacy Policy. ARINC operates in such a way that its single transmitter communicates in a point-to-point connection, thus requiring a significant amount of wiring which amounts to added weight. The network is designed in such a way that all critical traffic is prioritized using QoS policies so delivery, latency, and jitter are all guaranteed to be within set parameters.

Used for Integrity checking the message. Bi-directional communications must therefore require the specification of a complementary VL. Virtual links are unidirectional logic paths from the source end-system to all of the destination end-systems. Therefore, in a network with multiple switches cascaded star topologythe total number of virtual links is nearly limitless.

Each virtual link is allocated dedicated bandwidth [sum of all VL bandwidth allocation gap BAG rates x MTU] with the total amount of bandwidth defined by the system integrator. This type of network can significantly reduce wire runs and, thus, the overall weight of the aircraft. Retrieved from ” https: This frame include a supplemental layer called the EDE layer used for enhanced control, checking and time validation of the frame.

The drawback is that it requires custom hardware which can add significant cost to the aircraft. The six primary aspects of an AFDX data network include full duplexredundancy, determinism, high speed performance, switched and profiled network. Through the use of twisted pair or fiber optic cables, full-duplex Ethernet uses two separate pairs or strands for transmitting and receiving the data. The switch must also be non-blocking at the data rates that are specified by the system integrator, and in practice this may mean that the switch shall have a switching capacity that is the sum of all of its physical ports.


However, some features of a real AFDX switch may be missing, such as traffic policing and redundancy functions. Each VL is frozen in specification to ensure that the network has a designed maximum traffic, hence determinism. Real-time solution on the A” PDF.

The virtual link ID is a bit unsigned integer value that follows a constant bit field. Views Read Edit View history.

In one abstraction, it is possible to visualise the VLs as an ARINC style network each with one source and one or more destinations. However, the number sub-VLs that may be created in a single virtual link is limited to four. Also sub-virtual links do not provide guaranteed bandwidth or latency due to the buffering, but AFDX specifies that latency is measured from the traffic regulator function anyway. The VL ID is encoded in the destination address. Airbus and Rockwell Collins: The Sequence Numbers on successive frames must be in order.

Each switch has filtering, policing, and forwarding functions that should be able to process at least VLs. The following table shows the frame fields in order with the number of bytes for each.

The switches are designed to route an incoming frame from one, and only one, end system to a predetermined set of end systems.