arinc-664-ede-support完整原版文檔

ARINC664/AFDX?

EDEsupport

MX-Foundation4APIMAXIMAIRGUI

TECHNOLOGIES

Version2.1

PAGE

13

TableofContents

-AFDX/EDE 3

I-1.AFDXframelayout 3

…

….

…>

…

…

I-2.EDEMessageformat……………….………… 5

-MX-Foundation4-API 7

II-1.WorkwithAFDXonMX-Foundation4 7

II-2.WorkwithAFDX-EDEonMX-Foundation4 9

II-2.a.EDEsupportinAFDXCOMmode 10

II-2.b.EDEerrordetectionsupportinAFDXCOMmode………… 12

II-2.c.EDEsupportinRawmode…… 13

-MAXIMAIR 14

Conclusion 15

-AFDX/EDE

AFDXisanavionicsprotocolsupportedbyMAXTechnologies.

AFDXisaprotocoloverEthernetwithaddedsecuritytoavoiddatacollisionsandreachadeterministicformofEthernet.

AsAFDXisoverEthernet,somespecificationsofAFDXaresimilartotheonesforregularEthernet.EDEisafeatureaddedtoAFDXtoenhancethecommunicationreliability.

Thissection'sgoalistoclarifysomeofthemostimportantpointsofhowframesarebuilt.

-1.AFDXframelayout

AsshowninFigure1,theAFDXMessage(Payload)isencapsulatedin3mainotherlayers:

UDPlayer

IPlayer

MAClayer(headerandfooter)

PAYLOAD

UDP

PAYLOAD

IP

UDP

PAYLOAD

MAC

header

IP

UDP

PAYLOAD

MAC

footer

Figure1-Messageencapsulation

Eachlayerisreservedfordefinedfields.Onlymainfieldsaredetailedbelow.

#UDP:8bytes

UDPsourceport:Portusedbythesendingunit

UDPdestinationport:Porttobeusedbythereceivingunit

#IP:20bytes

IPsource:IPaddressoftheunitsendingtheframe

IPdestination:IPaddressoftheunitthathastoreceive

Fragmentation:AnIPDatagramcanbefragmentedintomultiplepackets,forexample,whenthemessagesizeistoolongforonedatagram.Ifthemessageisfragmented,aflagisraisedintheIPlayer.

Length:Sizeinbytesof[IP+UDP+Message]

#MACHeader:14bytes

MACsource:MACaddressofthesendingunit

MACdestination:MACaddressoftheunitthathastoreceivetheframe

VirtualLinkID:TheVirtualLink(VL)isakeycomponentofAFDX.AVLisacommunicationcanalbetweentwounits.AVLhasaspecifiedbandwidth,amaximumframesizeandminimumtimegapbetweentwoframes.ItisbecauseoftheVLspecificationsthattheAFDXisadeterministicEthernetprotocol.

#MACFooter:5bytes

MACFCS:FramechecksequenceMACSN:Sequencenumber

Figure2isanexampleofAFDXframe.Thebolddigitscorrespondtothefieldsdetailedabove.

A781

9DAD

4253

000C

0020 000026E500025218

76EE0CE4

7A

030000009012

0200 003A3029

08004500

0034

1A17

0000

0111 0B5B

0A2A2929

E0E0

8014

F3D3

F3D3

1100 000100000001211D

Figure2-Framelayout

Layer

Field

Exampleinhex

Exampleindecimal,whenrelevant

Payload

Usefuldata

Blue

UDP

SourcePort

F3D3

62419

UDP

DestinationPort

F3D3

62419

IP

SourceAddress

0A.2A.29.29

1

Layer

Field

Exampleinhex

Exampleindecimal,whenrelevant

IP

DestinationAdress

E0.E0.80.14

0

IP

Fragmentation

0000

IP

Length

0034

52bytes

MAC

Source

02:00:00:3A:30:29

MAC

Destination

03:00:00:00:90:12

MAC

VLID

(lasttwobytesofMACdestination)

9012

36882

MAC

FCS

76EE0CE4

MAC

SN

7A

-2.EDEMessageformat

TheErrorDetectionEncoding(EDE)hasbeenintroducedtoaddmorereliabilityonthecommunicationlevel.OnanetworksupportingEDEMessageformat,onlysomeVirtualLinksareEDEenabled.

EDEisnotalayerasMAC,IPandUDParelayers.EDEisenclosedinthepayloaditself.Itcomprisesofaheaderandafooter.

MAC

header

IP

PAYLOAD

EDE

footer

PAYLOAD

EDE

header

MAC

footer

UDP

Figure3-EDEMessagelayout

TheEDEsectioncontains4fields:

#EDEHeader

SN:Sequencenumber

Timestamp:Thisisthetimestampofwhentheframehasbeensent

#EDEFooter

CRCX:CRCcheckusingapolynomial

CRCY:CRCcheckusingasecondpolynomial

-MX-Foundation4-API

MX-Foundation4istheCAPIthatleveragestheFlexMultifamily.

MX-Foundation4isapowerfulAPIthatsupportsalloftheprotocolsavailableontheFlexMultis:

ARINC664/AFDX

ARINC429

ARINC825/CAN

ARINC717/FDR

ARINC708/WxRadar

ASYNCRS-232/422/485

MIL-STD-1553

Discrete

HDLC/SDLC

MX-Foundation4canbeusedforhostandembeddedapplications.

MX-Foundation4documentationisavailableonlinehere:

/mxf.

AchapterisdedicatedtoAFDXhere.Manyexamplesareincludedinthedocumentationaswell.

-1.WorkwithAFDXonMX-Foundation4

Thissectiondoesnotintendtoreplacetheactualdocumentationavailableonlineat

/

mxf.ThissectionwillonlypresentthemainkeystepsauserhastohaveinmindwhenstartingwithAFDXandAFDX-EDEonMX-Foundation4.

#Rawmodevs.AFDXCOMmode

Rawmodereceive:InRawmodetheacquisitionbu?ergetthedatadirectlyfromthephysicalport.ThisporthandleisusedforacquisitionandnoCOM/SAPportisrequired.Inthismodetheapplicationwillreadallthephysicalframesreceivedontheport(includingtheMAC,IP,UDPlayersandthepayload).

Rawmodetransmit:ARawportcanbeusedtosendaperiodicmessagesfromthephysicalporthandle.WithaRawport,theapplicationmustsupplyalltheheaders(MAC,IP,UDP)andthepayload.Bydefault,onlytheNetID,MACCRCandIPChecksumwillbecomputedbeforetransmission.

AFDXCOMmodereceive:ReceptionwithanAFDXCOMportusesthehandleoftheCOMporttoreceivemessages.Onlythepayloadisreturnedtotheapplication.TheMAC,IPandUDPlayersarecheckedagainsterrorsandarenotreturnedtotheapplication.

AFDXCOMmodetransmit:TransmissionwithanAFDXCOMportusesthehandleoftheCOMportforsendingmessages.MessageswillbeplacedinasubvlqueueandtransmittedaccordingtotheVLBAG.Onlythepayloadneedstobegiven,theprotocolstackwillfilluptheheaders(MAC,IP,UDP)basedontheVLcreationparameters.

#Errorinjectionsanddetections

Errordetections:ErrorsareautomaticallydetectedbyMX-Foundation4.Errorsthatcanbeautomaticallydetecteddependontheacquisitionmode.

InRawmode,theAPIwillcheckerrorsagainsttheframeitself,astheRawmodedoesnotparsetheheadersfromthepayload.InRawmode,theavailableerrorsare:

DatareceivedonphysicalportB

FrameCRC32errordetected

Preambletooshortortoolong

SFDerror

Frametoolong

InAFDXCOMmode,theerrordetectionmechanismallowsanyreceiveprotocolstackerrorandeventstobereportedtoacallingapplication.

Areceiveerrorcanbedetectedonanylayerofthestackdependingoftheframetypereceived;COM/SAPLayer,VLLayer,IP/UDPLayer,EDELayer,PhysicalPortsLayer.

UseRawmodetoworkwithentireframe(MAC,IP,UDP,payload).

UseAFDXCOMmodetoworkwiththepayloadonly.MAC,IPandUDPwillbevalidatedbytheAPIforyou.

#VirtualLinkdefinition

VirtualLinks(VL)havetobedefinedbytheusertoworkinAFDXCOMmode.VL’sparametersare:

Transmissionspecs

SpecifiessubVLIDandbagtime

Receptionspecs

Specifiesskewtime

FrameType

Choiceof:

StandardEthernetframe

ARINC664frame

Airbus664frame

Boeing664frame

MaximumFrameSize

LargestVLframesizethatcanbetransmittedontheVL.

BandwidthiscalculatedbydividingtheMaximumFrameSizewiththebagtime

II-2.WorkwithAFDX-EDEonMX-Foundation4

EDEissupportedbyMX-Foundation4andtheFlexMultis.ThesupportforEDEisfundamentallydi?erentdependingontheselectedmode.

AFDXCOMmode

RawMode

EDEenabled

EDEdisabled

InAFDXCOMmodewithEDEenabled,theuserworkswiththepayloadonly.TheMAC,IP,UDP,EDEare

calculatedautomatically.TheEDEisseenasalayer.

InAFDXCOMmodewithEDEdisabled,theuserworkswiththeEDE+payload.TheMAC,IP,UDParecalculatedautomatically.TheEDEisnotseenasalayer.

InRawmode,theuserworkswiththeentireframe.TheMAC,IP,UDPandEDE

havetobecalculatedbytheuser.

Transmit

Theuseronlyneedstocreatethepayloadtobesent.TheEDEheaderandfooterarecomputedandaddedtotheframeautomatically.UDP,IPandMACarealsoaddedautomatically.EDEerrorscanvoluntarilybeinjectedaswell.

Notpossibleastheapplicationdoesnotknowwhenpacketsistransmitted(dependsontheBAG).

Additionally,fragmentationcanalsocausemultiplepacketstobesentBAGratebutwithonlyonetransmitcall.

TotransmitandrespectEDEspecs,theprogramhastoincludetheEDEtimetag,EDECRCXandYandEDESequencenumberattherightplace.AstheFlexMultihasa10nstimingaccuracy,theEDEtimetagcaneasilybeinsertedbytheprogrammerwithagreattimeaccuracyfortransmissionoccurringinthefuture.

Receive

Whenframesarereceived,MAC,IP,UDPandEDEareremovedandcomputed.

TheAPIchecksforerrorsonallfourlayers.

Thepayloadonlyisprovidedtotheuser.MAC,IP,UDPandEDEerrortypesanddetailsarealsoprovided.

Whenframesarereceived,MAC,IPandUDPareremovedandcomputed.TheAPIchecksforerrorsonthesethreelayers.

TheEDE+payloadisprovidedtotheuser.MAC,IPandUDPerrortypesanddetailsarealsoprovided.

Rawmodeprovidesalllayersandpayloadtotheuser,includingEDElayer.JustasfortheMAC,IP,UDPlayers,theEDEheaderandfooterarenotcheckedagainstEDEerrors.

-2.a.EDEsupportinAFDXCOMmode

SectionII-1introducedthemostimportantpointsforAFDX.ForEDEsupportinAFDXCOMmode,threeotherpointshavetobesetproperly:

EDECRCpolynomials

VLEDEenabling/disabling

PortSID

#EDECRCPolynomials

TherearetwoCRCchecksinAFDX-EDE(seesectionI-2).TheyarecalledCRCXandCRCY.

Important:

Bydefault,theFlexMultisusethepolynomialsasintheEDEspecsfromBoeing(seeMXF_A664_FRAME_TYPE_BOEINGexamplebelow).Alternatively,theuserscanalsoentertheirownpolynomialsforCRCXandCRCY.OncethepolynomialsaredownloadedintotheFlexMultis,theywillbeusedfortransmitandreceiveservices.

vlParam.frameType=MXF_A664_FRAME_TYPE_BOEING;

#VLEDEenabling/disabling

AllVirtualLinks(VLs)arenotnecessarilyEDEenabledinasystem.ItisonlytwolinestoaddtotheVLdefinition.

vlParam.dir.Tx.Ede.enable=TRUEvlParam.dir.Rx.Ede.enable=TRUE

EnablingordisablingEDEonaVLletstheAPIknowiftheEDEheaderandfootershouldbeseenasalayer(likeMAC,IP,UDP)ornot(andbepartofthepayload)

WhentransmittingwithEDEenabled,theAPIandtheFlexMultiautomaticallycomputetheEDEheaderandfooterandaddthemtothepayload.Whenreceiving,theEDEheaderandfooterareremovedanderrorsarecheckedontheEDElayer.

WhentransmittingwithEDEdisabled,theAPIandtheFlexMultidonotdoanythingwithEDEheaderandfooter.TheuserneedstocreatetheEDEheaderandfootertheirselves.However,astheMAC,IP,UDPheadersareautomaticallycomputed,itisnotpossibleatthisstagetodeterminetheEDETimetag,northeEDESequenceNumberandEDECRCXandYinthecaseoffragmentation.Whenreceiving,theEDEheaderandfooterremaininthepayloadandarenotcheckedagainstEDEerrors.Theuserhastodoit.

#PortSID

TheSourceIdentifierDefinedforCOMporthastobeprovidedforeachport.

portParam.Ede.sid=0x0013

OncetheFrameType,theVLEDEEnabledandthePortSIDareset,theapplicationwillcomputetheEDEheaderandfooter.

Figure5-AFDX-EDEMessagereadinAFDX-COMmodewithEDEenabled

Figure6-AFDX-EDEMessagereadinAFDX-COMmodewithEDEdisabled

Figure5andFigure6showtheconsolesdisplayedbythesameapplicationwhenreceivingAFDX-EDEframesinAFDXCOMmode.

OnFigure5,EDEisenabled.EventhoughthereceivedframeshaveaEDEheaderandfooter,theyarenotdisplayed.TheEDEheaderandfooterhavebeencheckedagainstEDEerrorsandremovedtoshowonlythepayloadtotheuser.Thebluesectionshowsthepayload.

OnFigure6,EDEisdisabled.TheEDEheaderandfooteraredisplayed.TheEDEheaderandfooterhavenotbeencheckedagainstEDEerrors.

Blueispayload

RedisEDEheader,withfirsttheEDESequenceNumber(SN),andsecondtheEDETimetag

Greenisthefooter,withfirsttheEDECRCX,andsecondtheEDECRCY

II-2.b.EDEerrordetectionsupportinAFDXCOMmode

EDEerrordetectionisavailableonlyinAFDXCOMmodewithEDEenabled.

TheAPIchecksEDEerrorsintheEDEheaderandfooter.Detailsonavailablearegivenbelow.

TheEDEspecificationsarerespectedbytheFlexMultis.TheEDEspecificationsspecifyfourstepsoferrorchecking:

CRCXandCRCYerrorchecks

Ordinalcheck

Agecheck

Redundancycheck(onlyforredundantA/Bports)

ThesestepscanbeenhancedbyusingaEDEo?settable.ThisrequiresanEDEtimemanagerontheAFDXsystemandatableofdefinitionontheFlexMulti.IfyouwouldliketoseetheEDEo?settablesupportedbytheFlexMultis,pleaseletusknownow.WithnoEDEo?settable,theFlexMultisstillsupporttheEDEerrordetectionsasspecifiedintheEDEspecsforUnknownO?set.

Purpose

Checks

SupportedbyFlexMulti

CRC

ChecksifCRCXandCRCYarevalid

CRCXvalidity

?

CRCYvalidity

?

OrdinalCheck

Checksifpacketsarereceivedintherightorder

EDEtimestampincrement

?

EDESequenceNumberincrement

?

EDEOrdinalO?setconsistency

OnlyifO?settableisknown

Age

Checksifpacketsarenotexpired

EDETimetagO?setconsistency

OnlyifO?settableisknown

RedundancyManagement

ChecksifbothredundantportsA/Breceivedcoherentpackets

TimetagAvsBdelaycomparedtoSkewrateacceptation

?

TimetagAvsBdelaycomparedtoEDEO?setacceptation

OnlyifO?settableisknown

II-2.c.EDEsupportinRawmode

InRawmode,nolayersarecomputedbytheFlexMultis,northeAPI.

#Receiving

Whenreceiving,itmeansthatalloftheframeisretrievedandavailable.TheMAC,IP,UDPandEDE+payloadishandedtotheuser.Theuserhastocheckerrorsonthelayerthemselves.

#Transmitting

Whentransmitting,theuserhastocreatetheMAC,IP,UDPandEDE+payloadandsendthisviatheAPI.ThesectionbelowshowshowausercanformattheEDElayer.IfauserislookingforanautomatedcreationoftheMAC,IP,UDPandEDElayers,theusershouldbeusingAFDXCOMmodewithEDEenabled.

AsmentionedinsectionI-2,EDEisapartofthepayload.EDEissplitinaheaderandafooter.Headlinesaresuggestedbelowtocreatetheheaderandthefooter.

Header

Footer

CRCXandCRCY

SequenceNumber(SN)

Timetag

Definition

Sequencenumberisavaluethatincrementsitselfby1ateachnewframe

Timetagwhentheframehasbeentransmitted

TwoCRCchecksrelatingtotheEDE+Payload

Size

2bytes

6bytes

2bytesforeachCRC

Position

Frombytes0to1

Frombytes2to7

4lastbytesofthepayload

Suggestedimplementation

Counteradds1foreachframe.

Frameshavetobesentinthefuture,ontimetag.TheFlexMultiwillsendtheframeswitha10nsaccuracywithrespecttothetimetagasked.SimplyusetheexpectedtransmittimetagasyourEDEtimetag.

CRCcalculationsaccordingtotheCRCspecs.

OnFigure7,AFDX-EDEpacketsarereadinRawmode.TheMAC,IP,UDP,EDEandthepayloadaredisplayedandareavailabletotheuser.

Darkblueispayload

LightblueisEDEheaderandfooter

OrangeisUDPlayer

RedisIPlayer

PurpleisMAClayer

Figure7-AFDX-EDEMessagereadinRawmode

-MAXIMAIR

MAXIMAIRistheGraphicUserInterfacetoleveragetheFlexMultiswhenusingAFDXandAFDX-EDE.

MAXIMAIRisapowerfulinterfacethathelpsyoureadAFDX-EDEframes.UsingadefinitionfilemakesMAXIMAIRevenmorehelpful.ThedefinitionfilespecifiestheVLsthatareEDE-enabledandprovidestheSIDoftheports.ItalsocontainstheCRCXandCRCYpolynomialsusedinthegivensystem/aircraft.

Withthedefinitionfile,theEDElayersintherelevantEDEmessagesareautomaticallydecodedandEDEerrorsarechecked.MAXIMAIRautomaticallydecodesAFDX-EDEframes.Thereisnoactionrequiredfromtheuser.