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Imprint Document Title AFDX® / ARINC 664 Tutorial Document ID 700008_TUT-AFDX-EN_1000 Issue 1000 Classification Public Project AFDX® / ARINC 664 Realeased by TechSAT GmbH, Poing Release Date 29/08/2008 Copyright Notice This document is the property of TechSAT GmbH. Its content may not be copied or distributed to third parties without the written approval of TechSAT GmbH. The document has been checked carefully and is thought to be entirely reliable. However, no responsibility is assumed in case of inaccuracies. TechSAT GmbH reserves the right to make changes without further notice. © Copyright 2008 TechSAT GmbH • All rights reserved. Trademark Notice Product and other trademark names referred to within this manual are the property of their respective trademark holders. AFDX® is a registered trademark of Airbus Deutschland. AFDX® / ARINC 664 Tutorial 3/30 Contents Scope......................................................................................... 7 Overview.................................................................................... 9 Aircraft Data Network (ADN) Characteristics .............................................. 9 Emerging of AFDX.......................................................................................... 9 AFDX Characteristics................................................................................... 10 AFDX Network Architecture................................................... 11 Physical Topology........................................................................................ 12 Logical Topology.......................................................................................... 13 AFDX Communication Concept............................................. 15 The Virtual Link (VL)..................................................................................... 15 Virtual Link Scheduling ................................................................................... 15 Sub Virtual Links............................................................................................. 16 AFDX Port Types .......................................................................................... 17 AFDX Communication Ports........................................................................... 17 Receive Sampling Ports ........................................................................................17 Transmit Sampling Ports........................................................................................17 Receive Queuing Ports................................................................................... 17 Transmit Queuing Ports.........................................................................................17 Service Access Ports (SAP) ........................................................................... 18 Frame Fragmentation................................................................................... 18 AFDX Network Protocol ......................................................... 19 AFDX Protocol Stack.................................................................................... 19 AFDX Frame Structure ................................................................................. 20 Ethernet Preamble.......................................................................................... 20 Ethernet Protocol............................................................................................ 20 Ethernet Payload ............................................................................................ 20 Ethernet Error Control .................................................................................... 20 Ethernet Postamble ........................................................................................ 21 Network Reliability.................................................................. 23 Integrity Checking (IC) ................................................................................. 23 4/30 700008_TUT-AFDX-EN_1000 SN Usage in Transmitting Mode..................................................................... 24 SN Usage in Receiving Mode......................................................................... 24 Redundancy Management (RM).................................................................. 24 The AFDX Switch .................................................................... 25 Frame Filtering.............................................................................................. 26 Traffic Policing.............................................................................................. 26 AFDX Network Configuration ................................................ 27 Transmit Scheduling .................................................................................... 27 Transmit Scheduling Example........................................................................ 27 Bandwidth Allocation................................................................................... 29 List of Figures • Tables • Formulas AFDX® / ARINC 664 Tutorial 5/30 List of Figures Figure 1: AFDX network architecture ............................................................. 11 Figure 2: Physical topology of AFDX.............................................................. 12 Figure 3: Logical topology of AFDX................................................................ 13 Figure 4: VL scheduling with jitter................................................................... 15 Figure 5: Sub-VL Concept .............................................................................. 16 Figure 6: AFDX protocol stack........................................................................ 19 Figure 7: AFDX frame structure...................................................................... 21 Figure 8: AFDX Integrity Checking and Redundancy Management .............. 23 Figure 9: AFDX Switch Architecture............................................................... 25 List of Tables Table 1: AFDX protocol overhead including leading and trailing bytes.......... 29 List of Formulas Formula 1: Bandwidth constraints of messages on the same VL .................. 27 Formula 2: Example using Formula 1 for two messages on the same VL..... 28 Formula 3: AFDX message network load....................................................... 29 Formula 4: Bandwidth constraints from a message point of view .................. 30 Formula 5: Bandwidth constraints from a VL point of view ............................ 30 6/30 700008_TUT-AFDX-EN_1000 List of Abbreviations Abbreviation Text ADN Aircraft Data Network AFDX Avionics Full Duplex Switched Ethernet ARINC Aeronautical Radio Incorporated BAG Bandwidth Allocation Gap. BAG is a property of a VL and is given in ms BER Bit Error Ratio - The number of erroneous bits to the total bit number of bits COTS Commercial Of The Shelf CRC Cyclical Redundancy Checking. A data integrity detection method ES End System - LRU or part of an LRU implementing the network communication interface FCS Frame Check Sequence FIFO First In First Out IEEE802.3 Ethernet protocol standard from "Institute of Electrical & Electronics Engineers" IFG Inter Frame Gap IP Internet Protocol Jitter Network transmit latency caused by data contention Latency Network transmit latency caused by software and hardware layers in the ES LRU Line Replaceable Unit MAC Media Access Controller MTC Message Transmit Cycle. MTC is a property of a message and is given in ms MTU Maximum Transfer Unit. MTU is a property of a VL and is given in bytes PL Message payload data. PL is a property of a message and is given in bytes QoS Quality of Service RFC Request for Communication. Standard for protocols on top of IEEE802.3 RSN Redundancy Sequence Number SAP Service Access Point SFD Start Frame Delimiter TCP Transmission Control Protocol TFTP Trivial File Transfer Protocol UDP User Datagram Protocol VL Virtual Link. A virtual or logical communication channel AFDX® / ARINC 664 Tutorial 7/30 Scope The purpose of this tutorial is to give a description of the Avionics Full Duplex Switched Ethernet (AFDX®) which is a communication standard for an Aircraft Data Network (ADN). The description will provide the reader with an overview of the fundamentals of the AFDX network architecture, network protocol, network communication concept and network reliability. The tutorial is based on the standard ARINC 664 which is an AFDX standard defined by Aeronautical Radio, Incorporated (ARINC) and Airbus. Meanwhile Boeing has defined a special version of AFDX which is based on the ARINC 664 standard and is backwards compatible with this. However, the specialties of the Boeing standard are not described herein. It is assumed that the reader, as a minimum, is familiar with the principles of data communication. In particular, knowledge of the Ethernet communication standard is a definite advantage to understand the contents of this tutorial. |
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