ISO TR 13283-1998 Industrial automation - Time-critical communications architectures - User requirements and network management for time-critical communications.pdf

1、A Referencenumbe r ISO/TR13283:1998 (E) TECHNICAL REPORT ISO/TR 13283 Firstedition 19981215 IndustrialautomationTimecritical communicationsarchitecturesUser requirementsandnetworkmanagementfor timecriticalcommunicationssystems AutomatisationindustrielleArchitecturesdecommunicationsentemps relPrescri

2、ptionsdesutilisateursetgestionderseau pourlessystmesdecommunicationsentempsrelISO/TR13283:1998(E) ISO1998 Allrightsreserved.Unlessotherwisespecified,nopartofthispublicationmaybereproducedorutilizedinanyformorbyan ymeans,electronic ormechanical,includingphotocopyingandmicrofilm,withoutpermissioninwri

3、tingfromthepublisher. InternationalOrganizationforStandardization Casepostale56 CH1211Genve20 Switzerland Internet isoiso.ch PrintedinSwitzerland ii Contents Page 1Scope 1 2References. .1 2.1InternationalStandards 1 2.2Documentsunderdevelopment 2 3Termsanddefinitions .2 3.1TCCAterms . 2 3.2OSIBasicR

4、eferenceModelterms .4 3.3Serviceconventionterms . .4 3.4BasicReferenceModelofOpenDistributedProcessingterms. 4 3.5QoSBasicFrameworkterms .4 3.6TCNMterms. 6 4Userrequirementsfortimecriticalcommunicationssystems. 7 4.1Introduction. 7 4.2Transactionmodels. .8 4.3Usercontrol. 11 4.4Integrationissuesofop

5、enness. 12 4.5Timingrelatedissues .13 4.6Architectureconsiderations 16 4.7TCCSandOSI. .21 4.8TCCAnetworkmanagement 22 4.9NetworkmanagementinTCCN . 22 5QoSrequirementsfornetworkmanagementinTCCA 22 5.1Introduction. 22ISO ISO/TR13283:1998(E) iii 5.2Networkmanagementrequirements 23 6QoSmodelofTCNM 27 6.

6、1Introduction. 27 6.2Architecturalprinciples. . 28 6.3Informationexchanged 29 6.4QoSrequirementflow . . 29 6.5QoSdataflowbetween(N)subsystemandTCNM . 32 7QoScharacteristicsofTCCA 32 7.1Introduction. 32 7.2QoScharacteristics 33 8QoSmanagementfunctionsinTCNM . 44 8.1Introduction. 44 8.2Activityphaseso

7、fQoSmanagement . 45 8.3QoSmanagementfunctions. . 45 9MethodsandmechanismsfornetworkmanagementinTCCA 49 9.1Introduction. 49 9.2Networkmanagementmethodsandmechanisms 49ISO/TR13283:1998(E) ISO iv Foreword ISO(theInternationalorganizationforStandardization)isaworldwidefederationofnationalstandardsbodies

8、(ISO memberbodies).TheworkofpreparingInternationalStandardsisnormallycarriedoutthroughISOtechnical committees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhas therighttoberepresentedonthatcommittee.Internationalorganizations,governmentalandnongovernmental,in liaison

9、withISO,alsotakepartinthework.ISOcollaboratescloselywiththeInternationalElectrotechnical Commission(IEC)onallmattersofelectrotechnicalstandardization. ThemaintaskofISOtechnicalcommitteesistoprepareInternationalStandards.Inexceptionalcircumstancesa technicalcommitteemayproposethepublicationofaTechnic

10、alReportofoneofthefollowingtypes: type1,whenthenecessarysupportcannotbeobtainedforthepublicationofanInternationalStandard,despite repeatedefforts; type2,whenthesubjectisstillundertechnicaldevelopmentorwhereforanyotherreasonthereisthefuture butnotimmediatepossibilityofanagreementonanInternationalStan

11、dard; type3,whenatechnicalcommitteehascollecteddataofadifferentkindfromthatwhichisnormallypublished asanInternationalStandard(“stateoftheart”,forexample). TechnicalReportsoftypes1and2aresubjecttoreviewwithin3yearsofpublication,todecidewhethertheycan betransformedintoInternationalStandards.TechnicalR

12、eportsoftype3donotnecessarilyhavetobereviewed untilthedatatheyprovideareconsideredtobenolongervalidoruseful. ISO/TR13283,whichisaTechnicalReportoftype3,waspreparedbyTechnicalCommitteeISO/TC184, Industrial automationsystemsandintegration , SubcommitteeSC5, Architectureandcommunications . Itisbecoming

13、apparentthatintheirpresentformtheOSIStandardscannotreadilyaccommodatetimecritical communications.Thenetworkarchitectureswhichhavebeenstandardizedsofarwereprimarilyintendedfor generaltrafficandarenotalwayscapableofprovidingadequateperformanceandresiliencefortimecritical communications,especiallywhere

14、timecriticalandnontimecriticaltrafficcoexists.InparticularinmanyCIMand controlinstallationsthereappearstobearequirementforanintermediatenetwork,betweengeneralenterprise widenetworks(e.g.MAP)andthefieldbustypenetworks.Thisintermediatenetworkshouldcarrybothbulkdata transferadtimecriticalmessages,andbe

15、abletooperateoverconsiderabledistanceandinhostileenvironments. AtaskforcewasthereforesetupunderISO/TC184/SC5/WG2tolookatrequirementsforatimecritical communicationsarchitecture,concentratingparticularlyontherequirementsinintermediatenetworkandthus complementingworkdoneonrequirementsfortimecriticalcom

16、municationsinthefieldbusandtopreparea TechnicalReportonthetopic.Amongthoserequirementssomeareidentifiedtobeconsideredwhenmanaging timecriticalcommunicationsnetworkwherethespecifiedtimewindowmustberespectedbythecommunication systems.Themanagementandthesupportfortheserequirementsarethesecondpartofthis

17、TechnicalReport. TherelationshipwithotherstandardsisdepictedintheFigure1.ISO ISO/TR13283:1998(E) v QualityofServiceFramework QualityofService MethodsandMechanisms ISO/IECJTC1/SC21 BasicReferenceModel ManagementFramework ISO74984 BasicReference Model for ODP UserRe quirements for SystemSu pporting Ti

18、mecritical Communications NetworkMana gement for Timecritical CommunicationsS ystems Requirementsfor: Performance Security Accounting Configuration FaultManagement Figure1Relationshipwithotherstandards TimeCriticalNetworkManagement(TCNM)definesonlythoseadditionalrequirementsthatarenecessaryto manage

19、aTCCSnetwork.TCNMdoesnotdescribethesystemmanagementconsiderationregardingconfiguration management,accounting,security,andfaultmanagementexceptwherethesemightberequiredtosupportthetime criticalaspects;i.e.supportforTCNMdirectlyimpactsperformancemanagementtoagreatextent,butalsoimpacts otherareaswhichu

20、setimecriticalservicestoaccomplishtheirfunction. ThefocusofthisTechnicalReportistoidentifythecommunicationneedsoftightlycoupledcontrolsystems,andthe managementandsupportoftheseneeds.Thiseffortisintendedtocomplementeffortswhichhavefocusedon factoryinformationnetworks(e.g.MAP)whicharecharacterizedbyhi

21、ghthroughput,largepacketservicebetween informationprocessors(e.g.minicomputers)andcontrolprocessors(e.g.specialpurposecontrollers).Theeffortis alsointendedtocomplementeffortstoidentifysensornetworks(e.g.fieldbus)whichconcentrateonprovidingalow complexityinterfacetosimplefactoryfloorsensors,actuators

22、andotherdevices. Thereisnoclearconsensusonwhetherthetimecriticalcommunicationarchitectureshouldbeconnectionoriented orconnectionless.Eithersolutionisacceptableprovidingthattherequirementaremet;however,some requirementsmaybeeasiertomeetoneofthesesolutionsthatwiththeother.SinceMMSusesaconnection orien

23、tedsessionlayerthentheoverallservicemayappearconnectionorientedevenifthenetworkandtransport layersareconnectionless. ThisTechnicalReportsummarizestheuserrequirementsfortimecriticalcommunicationssystemsthathavebeen identifiedbythetaskforceandprovidesashortexplanationofeachoftherequirements.Considerat

24、ionisalsogiven tothemanagementandsupportoftheserequirements.ISO/TR13283:1998(E) ISO vi Introduction GeneralrequirementsforTCCS Atimecriticalcommunicationssystem(TCCS)isatypeofcommunicationsnetworksystemwhichisoptimizedfor communicationswheresequencesandtrafficpatternsvarydynamicallyoverawholenetwork

25、system.However, suchacommunicationsnetworksystemalsohastosupportprescheduledstaticsequencesofcommunications. Timecriticalcommunicationsarecommunicationsinwhichthereisaspecificboundedtimewindowwithinwhich oneormorespecifiedactionsmustbecompletedwithsomedefinedlevelofcertainly.ATCCSprovidesthe capabil

26、ityforbothtimecriticalmessagesandnontimecriticalmessagestocoexist.Inadistributedtimecritical application,algorithms,dataandcontrolstructuresarearoundnetworks.Suchadistributionisonlypossibleifthe communicationsystemsprovideacertainqualityofservice,particularlyregardingtimeconstraints,coherence,etc. I

27、tisrecognizedthatallTCCsystemsdifferfromothernetworksintheirrequirementforres ilience.Thetighterthe timeconstraintsare,themoreimportantstrategiesforresiliencebecome,sincenetworkscapableofmeetingtight timeconstraintsneedtoexhibitgreatresilienceifthedataflowisnottobeperturbedbyminorfaults. ATCCarchite

28、cturecomplieswiththeOSIBasicReferenceModelwheneverappropriate,meetingtheuser requirementsidentifiedinclause 4.CurrentOSIstandardscannotreadilyaccommodatetimecritical communicationsbecausetheirprimaryobjectivesaretoensurethetransferofgeneraldatatrafficortosatisfy intercommunicationbetweendeliveryofme

29、ssages.Therefore,thecurrentOSImodelandarchitectureneedstobe enhancedtosupportTCC. UserrequirementsforTCCS Automatedfactoriesusenetworksfordistributedcontrolapplications.Theseapplicationsrequirecommunications systemswhicharedesignedtoaccommodateworstcaseperformanceasopposedtoaverageperformance;in suc

30、hsystemstimelinessisofparamountimportance.Thenetworkshouldbeabletocopewithbothbulkdata transfersandtimecriticalmessagesandshouldsupportmethodsforachievingresilience. Ifnecessary,interfacingtheTCCSwiththemainfactorydatacommunicationnetworkshouldbeasimple procedure,usingalinkingdevice.Becauseoftherequ

31、irementtooperateinveryharshenvironments,highlyreliable mediaandsignalingmethodsarenecessarysothataverylowbiterrorrateresultsandaminimumnumberof retransmissionsisnecessary.Theuserneedstobeabletodefinecommunicationsprioritiesandcontrolerror recoverymechanisms.Networkmanagementfunctionsarenecessarytoal

32、locateresources,controlaccesstoTCC groups,detectlatentfailuresandactualfailures,etc. TheuserrequirementsthatareidentifiedallowtheconceptoftimewindowstoberealizedinOSI.Theinter relationshipbetweenTCCarchitecture,characteristicsorattributes,timewindowsandapplicationsrequiringtime criticalcommunication

33、saresetoutinFigure2.ISO ISO/TR13283:1998(E) vii anapplication requiringTCC timewindow metrics aTCCA structure characteristicsorattributes, temporalcoherence,etc . needs usedby describedby requires Figure2InterrelationshipbetweenTCCarchitecture,characteristics,timewindowsandapplications requiringtime

34、criticalcommunications NetworkmanagementinTCCA TherequirementsonnetworkmanagementareextractedandtranslatedfromtheuserrequirementsinTCCSin termsoftheprovisionofserviceswhichisessentialinordertomeetthetimeconstraintsspecifiedbyusersunder thecircumstancesinwhichthebehaviourofthetimecriticalcommunicatio

35、nsnetworksystemvariesdynamically. InthesenseoftheQoSBasicFramework,theQoSrequirementsareinformationtoexpresspartorallofthe networkmanagementrequirements,andareexpressedintermsofQoSparametersaspartofamechanismwhen aQoSrequirementisconveyedbetweenentities.Thisinformationcloselyconcernsapolicythatistoa

36、pplytothe operationofatimecriticalcommunicationsnetworksystem. Insometimecriticalapplicationsalluserrequirementsneednotalwaysbesatisfied.Itisthereforenotessentialfor aTCCAorthenetworkmanagementinaTCCAtomeetallthenetworkmanagementrequirementsidentifiedherein. Thismeansthattherewillbeallowableclassesw

37、hichmeetspecificsubsetsoftheserequirements.Theseclasses arenotaddressedinthisTechnicalReport.TECHNICALREPORT ISO ISO/TR13283:1998(E) 1 IndustrialautomationTimecriticalcommunications architecturesUserrequirementsandnetworkmanagementfor timecriticalcommunicationssystems 1Scope ThisTechnicalReportident

38、ifiesuserrequirementsforsystemssupportingtimecriticalcommunicationssystems andthenetworkmanagementaspectwhicharespecifictotimecriticalcommunicationsarchitectureinpeertopeer andmultipeercommunicationsinorbetweenapplicationprocesses. ThisTechnicalReporttranslatesuserrequirementsforsystemssupportingtim

39、ecriticalcommunicationsintoQoS requirementsforthemanagementandsupportofatimecriticalcommunicationsnetwork,usingtheconceptsand terminologyoftheQoSBasicFrameworkdevelopedbyISO/IECJTC1/SC21/WG7. ThisTechnicalReportalsodescribesamodel,characteristicsandfunctionsfornetworkmanagementintimecritical communi

40、cationssystems. ThisTechnicalReportfocusesontimecriticalcommunicationssystemsusedindiscretepartsmanufacturing applications;however,thesetimecriticalcommunicationssystemsmayalsobeusedinotherapplications,including processcontrol. ThisTechnicalReportconcentratesprimarilyontimecriticalcommunicationssyst

41、emsforeventdrivenapplications inwhichtrafficflowandnetworkconfigurationchangedynamically;however,thisTechnicalReportmayalsobe applicabletostatedrivenapplicationsinwhichtrafficpatternsandconfigurationarestatic. 2References Thefollowingstandardscontainprovisionswhich,throughreferenceinthistext,constit

42、uteprovisionsofthis TechnicalReport.Atthetimeofpublication,theeditionsindicatedwerevalid.Allstandardsaresubjecttorevision, andpartiestoagreementsbasedonthisTechnicalReportareencouragedtoinvestigatethepossibilityofapplying themostrecenteditionsofthestandardsindicatedbelow.MembersofIECandISOmaintainre

43、gistersofcurrently validInternationalStandards. 2.1International Standards ISO/IEC74981:1994, InformationtechnologyOpenSystemsInterconnectionBasicReferenceModel:The BasicModel. ISO/IEC74984:1989, InformationprocessingsystemsOpenSystemsInterconnectionBasicReference ModelPart4:Managementframework. ISO/IEC95061:1990, Industrialautomationsystems ManufacturingMessageSpecificationPart1:Service definition. ISO/IEC95062:1990, Industrialautomatio