61850-9-2IEC:2005(E) 2 57/800/CD CONTENTSFOREWORD ........................................................................................................................4INTRODUCTION ..................................................................................................................61 Scope ............................................................................................................................72 Normative references .....................................................................................................73 Terms and definitions .....................................................................................................94 Abbreviations .................................................................................................................95 Communication stack ...................................................................................................105.1 Overview of the protocol usage............................................................................105.2 Client/server services and communication profiles ...............................................115.2.1 Client/server services ..............................................................................115.2.2 A-Profile ..................................................................................................125.2.3 TCP/IP T-Profile ......................................................................................125.3 SV service and communication profile ..................................................................135.3.1 SV mapping overview ...............................................................................135.3.2 A-Profile ..................................................................................................135.3.3 T-Profile ..................................................................................................135.4 Restrictions .........................................................................................................156 Mapping of IEC 61850-7-2 and IEC 61850-7-3 Data Attributes ......................................167 Mapping of IEC 61850-7-2 classes and services ...........................................................167.1 Classes of SV data sets ....................................................................................... 167.2 Definition of SV data sets.....................................................................................168 Mapping of the model for the transmission of sampled values .......................................168.1 Overview.............................................................................................................168.2 Mapping of the multicast sampled value control block class and services .............168.2.1 Multicast sampled value control block definition .......................................168.2.2 MSV Services...........................................................................................198.3 Mapping of the unicast sampled value control block class and services................198.3.1 Unicast sampled value control block definition..........................................198.3.2 USV Services ...........................................................................................208.4 Mapping of the update of the sampled value buffer ..............................................218.5 Additional definitions for the transmission of sampled values ...............................218.6 Definitions for basic data types ............................................................................239 Conformance................................................................................................................239.1 Notation ..............................................................................................................239.2 PI CS....................................................................................................................239.2.1 Profile conformance .................................................................................239.2.2 SV Services .............................................................................................2410 Substation Configuration language (SCL) .....................................................................25Annex A (informative)ISO/IEC 8802-3 frame format and ASN.1 basic encoding rules..........26A.1 ISO/IEC 8802-3 frame format .......................................................................................26A.2 ASN.1 Basic Encoding Rules (BER)..............................................................................27A.3 Example for an ASN.1 coded APDU frame structure .......................................................28Annex B (informative)Process bus architectures................................................................29Annex C (informative)Multicast address selection..............................................................3161850-9-2IEC:2005(E) 3 57/800/CDFigure 1 OSI reference model and profiles .......................................................................10Figure 2 - Structure of the tag header .................................................................................14Figure 3 Concatenation of several ASDU's into one frame ................................................21Figure A.2 - Basic encoding rules format .............................................................................27Figure A.3 - Format of the tag octets...................................................................................27Figure A.4 - Example for an ASN.1 coded APDU frame structure ..........................................28Figure B.1 - Alternative process bus architectures...............................................................29Table 1 Service requiring client/server communication profile...........................................11Table 2 Service and protocols for client/server communication A-Profile...........................12Table 3 Service and Protocols for Peer TCP/IP T-Profile ..................................................12Table 4 Service requiring SV communication profile..........................................................13Table 5 Service and protocols for SV communication A-Profile..........................................13Table 6 SV T-Profile.........................................................................................................13Table 7 Default Virtual LAN I Ds and priorities ..................................................................14Table 8 Assigned Ethertype values ..................................................................................15Table 9 MMS TypeDescription definition for MSVCB MMS structure ....................................17Table 10 - DstAddress structure.......................................................................................... 18Table 11 Mapping of multicast sampled value services.....................................................19Table 12 MMS TypeDescription definition for USVCB MMS Structure ..................................19Table 13 Mapping of unicast sampled value services .......................................................20Table 14 Encoding for the transmission of the sampled value buffer .................................22Table 15 Encoding for the basic data types ......................................................................23Table 16 PI CS for A-Profile support ..................................................................................24Table 17 PI CS for T-Profile support ..................................................................................24Table 18 SV conformance statement ................................................................................24Table 19 Definitions for SV SCL .......................................................................................25Table C.1 Recommended multicast addressing example ..................................................3161850-9-2IEC:2005(E) 4 57/800/CD INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________COMMUNICATION NETWORKS AND SYSTEMS IN SUBSTATIONS Part 9-2: Specific Communication Service Mapping (SCSM) Sampled values over ISO/IEC 8802-3 FOREWORD1)The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising allnationalelectrotechnicalcommittees(IECNationalCommittees).TheobjectofIECistopromote internationalco-operationonallquestionsconcerningstandardizationin theelectricalandelectronic fields.To thisendandinadditiontootheractivities,IECpublishesInternationalStandards,TechnicalSpecifications, TechnicalReports,PubliclyAvailableSpecifications(PAS)andGuides(hereafterreferredtoasIEC Publication(s)). Their preparation is entrustedto technical committees; any IEC National Committee interested inthesubjectdealtwithmayparticipateinthispreparatorywork.International,governmentalandnon-governmentalorganizationsliaisingwiththeIECalsoparticipateinthispreparation.IECcollaboratesclosely withtheInternationalOrganizationforStandardization(ISO)inaccordancewithconditionsdeterminedby agreement between the two organizations. 2)TheformaldecisionsoragreementsofIEContechnicalmattersexpress,asnearlyaspossible,an internationalconsensusofopinionontherelevantsubjectssinceeachtechnicalcommitteehasrepresentation from all interested IEC National Committees.3)IECPublicationshavetheformofrecommendationsforinternationaluseandareacceptedbyIECNational Committeesinthatsense.WhileallreasonableeffortsaremadetoensurethatthetechnicalcontentofIEC Publicationsisaccurate,IECcannotbeheldresponsibleforthewayinwhichtheyareusedorforany misinterpretation by any end user. 4)Inordertopromoteinternationaluniformity,IECNationalCommitteesundertaketoapplyIECPublications transparentlytothemaximumextentpossibleintheirnationalandregionalpublications.Anydivergence betweenanyIECPublicationandthecorrespondingnationalorregionalpublicationshallbeclearlyindicated in the latter. 5)IECprovidesnomarkingproceduretoindicateitsapprovalandcannotberenderedresponsibleforany equipment declared to be in conformity with an IEC Publication. 6)All users should ensure that they have the latest edition of this publication. 7)NoliabilityshallattachtoIECoritsdirectors,employees,servantsoragentsincludingindividualexpertsand members of its technicalcommittees and IEC National Committees for any personal injury,property damage or otherdamageofanynaturewhatsoever,whetherdirectorindirect,orforcosts(includinglegalfees)and expensesarisingoutofthepublication,useof,orrelianceupon,thisIECPublicationoranyotherIEC Publications.8)AttentionisdrawntotheNormativereferencescitedinthispublication.Useofthereferencedpublicationsis indispensable for the correct application of this publication. 9)AttentionisdrawntothepossibilitythatsomeoftheelementsofthisIECPublicationmaybethesubjectof patent rights. IEC shall not be held responsible for identifying any or all such patent rights. InternationalStandardIEC 61850-9-2hasbeenpreparedbyIEC technicalcommittee57: Power systems management and associated information exchange. The text of this standard is based on the following documents: FDISReport on voting 57/690/FDIS57/709/RVD Fullinformationonthevotingfortheapprovalofthisstandardcanbefoundinthereporton voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. 61850-9-2IEC:2005(E) 5 57/800/CDIEC 61850 consists of the followi ng parts, under the general titl e Communi cation networks and systems in substations: Part 1:Introduction and overviewPart 2:GlossaryPart 3:General requirements Part 4:System and project management Part 5:Communication requirements for functions and device models Part 6:Configurationdescriptionlanguageforcommunicationinelectricalsubstations related to I EDsPart 7-1:BasiccommunicationstructureforsubstationandfeederequipmentPrinciples and modelsPart 7-2:BasiccommunicationstructureforsubstationandfeederequipmentAbstract communication service interface (ACSI )Part 7-3:BasiccommunicationstructureforsubstationandfeederequipmentCommon data classesPart 7-4:BasiccommunicationstructureforsubstationandfeederequipmentCompatible logical node classes and data classesPart 8-1:SpecificCommunicationServiceMapping(SCSM)MappingstoMMS(ISO 9506-1 and ISO 9506-2) and to ISO/IEC 8802-3 Part 9-1: SpecificCommunicationServiceMapping(SCSM)Sampledvaluesoverserial unidirectional multidrop point to point link Part 9-2:SpecificCommunicationServiceMapping(SCSM)Sampledvaluesover ISO/IEC 8802-3 Part 10:Conformance testing 61850-9-2IEC:2005(E) 6 57/800/CD INTRODUCTIONThis part of IEC 61850 defines the SCSM for sampled values over ISO/IEC 8802-3. The intent ofthisSCSMdefinitionistosupplementIEC 61850-9-1toincludethecompletemappingof the sampled value model. ThispartofIEC 61850appliestoelectroniccurrentandvoltagetransformers(ECTandEVThavingadigitaloutput),mergingunits,andintelligentelectronicdevicesforexample protection units, bay controllers and meters. ProcessbuscommunicationstructurescanbearrangedindifferentwaysasdescribedinAnnex BandIEC 61850-1.Inadditiontothetransmissionofsampledvaluedatasets,which aredirectlyconnectedtoISO/IEC 8802-3,aselectionofIEC 61850-8-1servicesare necessarytosupporttheaccesstotheSVcontrolblock.Referencestotherelevant IEC 61850-8-1servicesareprovidedinthisSCSM.Forlesscomplexdevices(forexample merging units)the sampled valuecontrol blockcanbe pre-configured, in which case there is no need to implement IEC 61850-8-1 services based on the MMS-Stack. Thisdocumentdefinesthemappingofsampledvalueclassmodel(IEC 61850-7-2)to ISO/IEC 8802-3.ThisSCSM,incombinationwithIEC 61850-7andIEC 61850-6,allows interoperability between devices from different manufacturers.Thisstandarddoesnotspecifyindividualimplementationsorproducts,nordoesitconstrain theimplementationofentitiesandinterfaceswithinacomputersystem.Thisstandard specifiestheexternallyvisiblefunctionalityofimplementationstogetherwithconformance requirements for such functionalities. Thissecondeditionissolvingtechnicalissuesthathavebeenidentifiedwhileimplementing IEC 61850. Reading Guide This document is an extended mapping specification of IEC 61850-9-1 and IEC 61850-8-1 to cover sampled value transmission over ISO/IEC 8802-3. Thisdocumentcanbestbeunderstoodifthereaderisthoroughlyfamiliarwith IEC 61850-7-1, IEC 61850-7-2, IEC 61850-7-3 and IEC 61850-7-4.The ACSIservices defined in IEC 61850-7-2 are not explained in this part of the standard.61850-9-2IEC:2005(E) 7 57/800/CDCOMMUNICATION NETWORKS AND SYSTEMS IN SUBSTATIONS Part 9-2: Specific Communication Service Mapping (SCSM) Sampled values over ISO/IEC 8802-3 1Scope ThispartofIEC 61850definestheSpecificCommunicationServiceMapping(SCSM)forthe transmission of sampled values according to the abstract specification in IEC 61850-7-2. The mappingisthatoftheabstractmodelonamixedstackusingdirectaccesstoan ISO/IEC 8802-3 link for the transmission of the samples in combination with IEC 61850-8-1. Each SCSM consists of three parts:a specification of the communication stack being used, themappingoftheabstractspecificationsofIEC 61850-7ontherealelementsofthe stack being used, and theimplementationspecificationoffunctionality,thatisnotcoveredbythestackbeing used.2Normative references Thefollowingreferenceddocumentsareindispensablefortheapplicationofthisdocument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60874-10-1,Connectorsfor optical fibres and cables Part 10-1: Detail specification for fibre optic connector type BFOC/2,5 terminated to multimode fibre type A1 IEC 60874-10-2,Connectorsfor optical fibres and cables Part 10-2: Detail specification for fibre optic connector type BFOC/2,5 terminated to single-mode fibre type B1IEC 60874-10-3,Connectorsfor optical fibres and cables Part 10-3: Detail specification for fibre optic adaptor type BFOC/2,5 for single and multimode fibreIEC 61850-7-1,CommunicationnetworksandsystemsinsubstationsPart7-1:Basic communicationstructureforsubstationandfeederequipmentPart7-1:Principlesand modelsIEC 61850-7-2,CommunicationnetworksandsystemsinsubstationsPart7-2:Basic communicationstructureforsubstationandfeederequipmentAbstractcommunication service interface ( )IEC 61850-7-3,CommunicationnetworksandsystemsinsubstationsPart7-3:Basic communication structure for substation and feeder equipment Common data classesIEC 61850-7-4,CommunicationnetworksandsystemsinsubstationsPart7-4:Basic communicationstructureforsubstationandfeederequipmentCompatiblelogicalnode classes and data classesIEC 61850-8-1,CommunicationnetworksandsystemsinsubstationsPart8-1:Specific CommunicationServiceMapping( )Mappingsto(ISO 9506-1andISO9506-2) and to ISO/IEC 8802-361850-9-2IEC:2005(E) 8 57/800/CD IEC 61850-9-1,Communicationnetworksandsystemsinsubstations Part9-1:Specific CommunicationServiceMapping( )Sampledvaluesoverserialunidirectional multidrop point to point linkISO/IEC 7498-1:1994,InformationtechnologyOpenSystemsInterconnectionBasic Reference Model: The Basic ModelISO/IEC 8326:1996,InformationprocessingsystemsOpenSystemsInterconnection Session service definition ISO/IEC 8327-1:1997, Information technology Open Systems Interconnection Connection-oriented session protocols: Protocol specificationISO/IEC 8649:1996,InformationtechnologyOpenSystemsInterconnectionService definition for the Associated Control Service ElementISO/IEC 8650-1:1996, Information technology Open Systems Interconnection Connection-oriented protocol for the Association Control Service Element: Protocol specificationISO/IEC 8802-3:2001,InformationtechnologyTelecommunicationsandinformation exchangebetweensystemsLocalandmetropolitanareanetworksSpecificrequirements Part3:Carriersensemultipleaccesswithcollisiondetection(CSMA/CD)accessmethod and physical layer specifications ISO/IEC 8822:1994,InformationtechnologyOpenSystemsInterconnectionPresentation service definition ISO/IEC 8823-1:1994, Information technology Open Systems Interconnection Connection-oriented presentation protocol: Protocol specificationISO/IEC 8824-1:1999,InformationtechnologyAbstractSyntaxNotationOne(ASN.1): Specification of basic notation Amendment 1 (2000) Amendment 2 (2000) ISO/IEC 8825-1,Informationtechnologyencodingrules:SpecificationofBasic EncodingRules( ),CanonicalEncodingRules(CER)andDistinguishedEncodingRules (DER)ISO 9506-1:2003,IndustrialautomationsystemsManufacturingMessageSpecification Part 1: Service definitionISO 9506-2:2003,IndustrialautomationsystemsManufacturingMessageSpecification Part 2: Protocol specificationIEEE 754:1985, IEEE Standard for Binary Floating-Point ArithmeticIEEE802.1Q:1998,IEEEStandardsforLocalandMetropolitanAreaNetworks:Virtual Bridged Local Area Networks RFC 791, Internet Protocol; IETF, available at RFC 792, Internet Control Message Protocol; IETF, available at RFC 793, Transmission Control Procedure; IETF, available at RFC826,AnEthernetAddressResolutionProtocolorConvertingNetworkProtocol Addressesto48.bitEthernetAddressforTransmissiononEthernetHardware;IETF, available at RFC894,AStandardfortheTransmissionofIPdatagramsoverEthernetNetworks;IETF, available at RFC 919, Broadcasting Internet Datagrams; IETF, available at 61850-9-2IEC:2005(E) 9 57/800/CDRFC1006ISOtransportservicesontopofTCP:Version3;IETF,availableat

RFC 1112, Host Extensions for IP Multicasting; IETF, available at 3Terms and definitions For the purposes of this document, the definitions given in IEC 61850-2 apply.4Abbreviations ACSI Abstract Communication Service Interface ASDU Application Service Data Unit ASN.1 Abstract Syntax Notation number One APCI Application Protocol Control Information APDU Application Protocol Data Unit APPI D Application Identifier AUI Attachment Unit Interface BERASN.1 Basic Encoding Rules BS Bitstring cConditional support. The item shall be implemented if the stated condition existsCFI Canonical Format Identifier CSMA/CD Carrier Sense Multiple Access/Collision Detection DF Data Frame DO Data Object ECT Electronic Current Transformer EVT Electronic Voltage Transformer F/S Functional Standard GOOSE Generic Object Oriented Substation Event GSSE Generic Substation Status Event iOut-of-scope: The implementation of the item is not within the scope of this standardI CDI ED Configuration Description I ED Intelligent Electronic Device LSDU Link Layer Service Data Unit mMandatory support. The item shall be implemented. MAC Media Access Control MAU Medium Attachment Unit MMS Manufacturing Message Specification (ISO 9506) MSVCB Multicast Sampled Value Control Block MU Merging Unit oOptional support. The implementor may decide to implement the item 61850-9-2IEC:2005(E) 10 57/800/CD PDU Protocol Data Unit PI CS Protocol Implementation Conformance Statement SCSM Specific Communication Services Mapping rreadable RI F Routing Information Field (ISO/IEC 8802-5) SV Sampled Value TCI Tag Control Information TPI D Tag Protocol Identifier USVCBUnicast Sampled Value Control Block VI DVLAN Identifier VLAN Virtual Local Area Network VMD Virtual Manufacturing Device w WriteablexExcluded: The implementor shall not implement this item XML Extensible Markup Language 5Communication stack 5.1Overview of the protocol usage TheOSIreferencemodel(ISO/IEC 7498-1)definesamodelbasedupontheconceptof layering of communication functions. The model includes 7 layers and specifies the functional requirementsforeachlayertoachievearobustcommunicationsystem.Themodeldoesnot specifytheprotocolstobeusedtoachievethefunctionality,nordoesitrestrictthesolution to a single set of protocols.Figure 1 OSI reference model and profiles TheuseofISOApplication(A-Profile)andTransport(T-Profile)Profiles(seeFigure1) describesthevariousstackprofiles.AnISOA-Profileisthesetofspecificationsand agreementsrelatingtotheupperthree(3)layersoftheISOOSIreferencemodel(for exampletheapplication,presentation,andsessionlayers).AnISOT-Profileisthesetof specificationsandagreementsrelatingtothelowerfour(4)layersoftheISOOSIreference model (for example the transport, network, datalink and physical layers). TwocombinationsofA-ProfilesandT-Profilesaredefinedinordertosupportthe transmissionofsampledvaluesincludingtheaccesstotheassociatedSVcontrolblock,as specified in IEC 61850-7-2. The two different combinations are used for: ApplicationPresentationSession TransportNetworkDataLinkPhysicalA-ProfileT-ProfileIEC 096/0461850-9-2IEC:2005(E) 11 57/800/CDclient/server services based on MMS in accordance to IEC 61850-8-1; SV services based on data link layer. 5.2Client/server services and communication profiles 5.2.1Client/server services Thisclient/servercommunicationprofileshallbeusedinadditiontotheSVcommunication profile according to5.3ifan access tothesampledvaluecontrol blockvia client isrequired. Thisprofileshallbeusedforanyimplementationclaimingconformancetothisstandardand declaring support for one of the following IEC 61850-7-2 services in Table 1. Table 1 Service requiring client/server communication profile IEC 61850-7-2 modelIEC 61850-7-2 service ServerGetServerDirectory AssociationAssociate Abort Release Logical deviceGetLogicalDeviceDirectory Logical nodeGetLogicalNodeDirectory GetAllDataValuesDataGetDataValues SetDataValues GetDataDirectory GetDataDefinition Data setGetDataSetValues SetDataSetValues CreateDataSet DeleteDataSet GetDataSetDirectory SV class modelGetMSVCBValuesSetMSVCBValuesGetUSVCBValuesSetUSVCBValues61850-9-2IEC:2005(E) 12 57/800/CD 5.2.2A-Profile Table 2 shows services and protocols of the A-Profile client/server. Table 2 Service and protocols for client/server communication A-Profile SpecificationOSI model layer NameService specification Protocolspecificationm/oManufacturingmessagespecificationISO 9506-1:2000ISO 9506-2:2000mApplicationAssociation control service element ISO/IEC 8649:1996ISO/IEC 8650-1:1996m Connection oriented presentationISO/IEC 8822:1994ISO/IEC 8823-1:1994mPresentationAbstract syntaxISO/IEC 8824-1:1999ISO/IEC 8825-1m SessionConnection oriented sessionISO/IEC 8326:1996ISO/IEC 8327-1:1997m There is only one T-Profile (TCP/IP) that may be used by the client/server A-Profile.5.2.3TCP/IP T-Profile Table 3 shows services and protocols of the TCP/IP T-Profile client/server. Table 3 Service and Protocols for Peer TCP/IP T-Profile SpecificationOSI model layer NameService specificationProtocolspecificationm/oISO transport on top of TCPRFC 1006m Internet Control Message Protocol (ICMP)RFC 792m TransportTransmission Control Protocol (TCP)RFC 793m Internet protocolRFC 791 Converting network protocol addressRFC 826 (Address Resolution Protocol: ARP) mBroadcasting internet datagramsRFC 919m Network Host extensions for IP multicastingRFC 1112m Standard for the transmission of IP datagrams over Ethernet networks RFC 894mDataLinkCarrier Sense Multiple Access with Collision Detection (CSMA/CD)ISO/IEC 8802-3:2001m Fibre optic transmission system 100Base-FXISO/IEC 8802-3:2001c1Physical Basic optical fibre connector NOTEThis is the specification for the ST connector.IEC 60874-10-1, IEC 60874-10-2 and IEC 60874-10-3 c1c1 Recommended, but future technology could be used. 61850-9-2IEC:2005(E) 13 57/800/CD5.3 SV service and communication profile 5.3.1 SV mapping overview This SV communication profile shall be used for any implementation claiming conformance to thisstandardanddeclaringsupportforoneofthefollowingIEC 61850-7-2servicesinTable 4.Table 4 Service requiring SV communication profile ModelIEC 61850-7-2 service Multicast sampled value class modelMulticast SV message Unicast sampled value class modelUnicast SV message 5.3.2A-Profile Table 5 shows services and protocols of the A-Profile SV.Table 5 Service and protocols for SV communication A-Profile Specification OSI model layer NameService specificationProtocol specification m/oApplication SV servicem PresentationAbstract syntaxISO/IEC 8824-1:1999ISO/IEC 8825m Session Presentation layer: see additional definitions in 8.5. Application layer: see additional definitions in 8.5. 5.3.3T-Profile The T-Profile for SV Services is shown in Table 6. Table 6 SV T-ProfileSpecificationOSI model layer NameService specificationProtocol specification m/oTransport Network Priority tagging/VLAN IEEE 802.1QmDataLinkCarrier Sense Multiple Access with Collision Detection (CSMA/CD)ISO/IEC 8802-3:2001m Fibre optic transmission system 100Base-FX ISO/IEC 8802-3:2001c1Physical Basic optical fibre connectorNOTEThis is the specification for the ST connector.IEC 60874-10-1, IEC 60874-10-2 and IEC 60874-10-3c1 c1 Recommended, but future technology could be used. 61850-9-2IEC:2005(E) 14 57/800/CD Physical layer: Specifications for the Medium Attachment Unit (MAU)Theopticalfibretransmissionsystem100Base-FXaccordingtoISO/IEC 8802-3is recommendedasindicatedabovebecauseofrequirementsrelatingtotheelectromagnetic environment.Link layer: Ethernet addresses ThedestinationISO/IEC 8802-3multicast/unicastaddresshastobeconfiguredforthe transmissionofsampledvalues.AuniqueISO/IEC 8802-3sourceaddressshallbeused. Recommendations of multicast address range assignments are given in Annex C. Link layer: Priority tagging/virtual LAN PrioritytaggingaccordingtoIEEE802.1Qisusedtoseparatetimecriticalandhighpriority bus traffic for protection relevant applications from low priority busload.See Figure 2 for the structure of the tag header. Octets87654321 0 1TPID0 8100 (as per 802.1Q) 2User priorityCFI VID 3TCIVIDKey TPID (Tag Protocol Identifier) Field: Indicates the Ethernet Type assigned for 802.1Q Ethernet encoded frames. This value shall be 0x8100. TCI (Tag Control Information) Fields: UserPriority:BS3;Userpriorityvalueshallbesetbyconfigurationtoseparatesampledvaluesfromlowpriority busload. If the priority is not configured then the default values of Table 7 shall be used. CFI (Canonical Format Indicator): BS1 [0]; A single bit flag value. For this standard the CGI bit value shall be reset (value = 0). NOTEIfset(value=1),anEmbeddedResourceIdentificationField(E-RIF)followstheLength/Typefieldinthe ISO/IEC 8802-3 tagged frame. VID:VirtualLANsupportisoptional.Ifthismechanismwillbeused,theVLANIdentifier(VID)shallbesetby configuration, if it is not used, it shall be set to zero (0). NOTEAsIEEE802.1Qallowsimplementationwitharestrictedsetofpriorities,thehigherpriorityframesshould haveapriorityof4to7andthelowerpriorityshouldhaveapriorityof1to3.Thevalue1isthepriorityof untagged frames thus 0 should be avoided as it may cause unpredictable delay due to normal traffic. Additionally,sinceSampledValuesneedstohavepotentiallyitsownbandwidthallocation,itsconfiguredVIDwill be different from GOOSE and GSE. The default values for priority and VI D shall be as defined in Table 7.Figure 2 - Structure of the tag header Table 7 Default Virtual LAN I Ds and priorities ServiceDefault VI D Default priority Sampled Values04 The general ISO/IEC 8802-3 frame structure for sampled values can be found in Annex A. IEC 097/04 61850-9-2IEC:2005(E) 15 57/800/CDLink layer: Ethertype and other header information EthertypesbasedonISO/IEC 8802-3MACSublayerareregisteredbytheIEEEauthority registration.GSEmanagement,GOOSEandsamplesvaluesshallbedirectlymappedtothe reserved Ethertype(s) and the Ethertype PDU. The assigned values are found in Table 8. Table 8 Assigned Ethertype values UseEthertype value (hexadecimal)APPI D type IEC 61850-8-1 GOOSE 88-B80 0 IEC 61850-8-1 GSE Management88-B90 0 IEC 61850-9-1 Sampled Values88-BA0 1 IEC 61850-9-2 Sampled Values88-BA0 1 The Ethertype PDU and APDU octets shall be as defined in annex A. NOTEAPPI D:applicationidentifier.TheAPPI DisusedtoselectISO/IEC8802-3framescontainingsampledvalue messages and to distinguish the application association.ThevalueofAPPI DisthecombinationoftheAPPI Dtype,definedasthetwomostsignificantbitsofthevalue(as defined in Table 8), and the actual I D.Thereservedvaluerangeforsampledvaluesis0x4000to0x7FFF.IfnoAPPI Disconfigured,thedefaultvalue shall be 0x4000. The default value is reserved to indicate lack of configuration. It is strongly recommended to have unique,sourceorientatedSV APPI Dwithinasystem,inordertoenableafilteronlinklayer.Theconfigurationof APPID should be enforced by the configuration system. Length:NumberofoctetsincludingtheEthertypePDUheaderstartingatAPPID,andthelengthoftheAPDU (Application Protocol Data Unit). Therefore, the valueof Length shall be 8 + m,where m is the length of the APDU and m is less than 1492. Frames with inconsistent or invalid length field shall be discarded. The Reserved1 and Reserved2 are reserved for future standardized applications and shall be set to 0 as default. 5.4Restrictions ThismappingisrestrictedtothemappingoftheACSI modelforthetransmissionofsampled values.Themodelappliestodatasets.TogetfullbenefitofIEC 61850,additionalACSImodelsneedtobesupportedinaccordanceto IEC 61850-8-1. As anexample,toenablethe transmissionofsampledvaluebuffer,theassociatedcontrolblockattributeSvEnashallbe written. However, if the client will read a list of available data sets or the contents of the data set,furthermodels(forexamplelogicaldevice,logicalnodeordataset)needtobe supported.Thismappingspecifiesthetransmissionofdatasetsrelatedtothesampledvaluemodelin additiontotheuniversaldatasetspecifiedinIEC 61850-9-1ofthisstandard.Thedataset statusindication,whichisalsodefinedinIEC61850-9-1,isnotsupported,becauseother communication methods are available for transmission of binary status indications.DatasetsforsampledvalueswillbespecifiedbyusingtheXMLlanguage(exceptthe universaldatasetwhichisdefinedinIEC61850-9-1)onengineeringlevelinaccordancewith IEC 61850-6 of this standard to ensure interoperability.Forthetransmissionofsampledvaluedatasets,theASN.1BasicEncodingRules(BER)will be usedincombinationwithtagsnotationharmonisedwiththeMMSgrammarusedin IEC 61850-8-1. 61850-9-2IEC:2005(E) 16 57/800/CD 6 Mapping of IEC 61850-7-2 and IEC 61850-7-3 Data Attributes The mapping of attributes and common data attributes to MMS are specified in IEC 61850-8-1.ForthetransmissionofsampledvaluestheASN.1,theBasicEncodingRules(BER)andthe common data classes defined in IEC 61850-7-3 of this standard apply.7Mapping of IEC 61850-7-2 classes and services 7.1Classes of SV data sets If a client/server association based on MMS is used in addition to the transmission of SV data sets, the definitions of IEC 61850-8-1 apply for the following classes: server class model; association model; logical device model; logical node model; data class model; data set class model. 7.2Definition of SV data sets Forthe transmissionofsampledvalues, thedatasets are defined in logical node "LLN0". All sampledvaluedatasetsspecificationarepartoftheI EDConfigurationDescription(I CD),except the universal data set, which is fixed and defined in IEC 61850-9-1 of this standard.NOTEItisassumedthatthedatasetsusedforthetransmissionofsampledvaluesmayincludedataobjects from more than one logical node and are therefore allocated in LLN0. 8Mapping of the model for the transmission of sampled values 8.1Overview To ensure interoperability, the data sets for sampled values are specified in XML according to the definition in clause 6 of this standard.Thesampledvalueclassmodelprovidesreportingofsampledvaluedatasetsinan organisedandtimecontrolledway,sothattransferisveryfastandtimeoftransferiskept constant.Sampledvaluecontrolblockforunicastandmulticastdefinesthetransmission characteristics of the data set they refer to. A detailed description is given in IEC 61850-7-2. 8.2Mapping of the multicast sampled value control block class and services 8.2.1Multicast sampled value control block definition Thesampledvaluecontrolblock,asdefinedinIEC 61850-7-2,shallbepre-definedby configuration orshallbemapped toanMMSMulticast SampledValueControlBlock (MSVCB)as defined in Table 9. All MSVCB components shall be of the functional constraint MS. 61850-9-2IEC:2005(E) 17 57/800/CDTable 9 MMS TypeDescription definition for MSVCB MMS structure MMS component nameMMSTypeDescription r/wm/o Condi-tionCommentsMsvCBNam IdentifierrmMMS Identifier of the structure of the MsvCBName within the MMS object named: LLN0$MV e.g. LLN0$MS$ MsvCBRef Visible-stringrmThe value of this component shall contain the IEC Reference of the MsvCB. e.g./LLN0$MS$SvEnaBooleanr/wmTRUE = transmission of sampled value buffer is activated. FALSE = transmission of sampled value buffer is deactivated. MsvI D Visible-stringrmSystem wide unique identification. DatSet Visible-stringrmThe value of this component shall contain the IEC Reference of the DataSet conveyed by the MsvCB.This ObjectReference shall be limited to VMD or Domain scoped NamedVariableLists.ConfRevIntegerrmCount of configuration changes regard to MSVCB.SmpRateIntegerrmAmount of samples per period. OptFldsBitString refresh-timeBooleanr m TRUE = SV buffer contains the attribute RefrTmFALSE = attribute RefrTm is not available in the SV buffer. sample-synchronisedReservedBooleanrmTRUE = SV buffer contains the attribute SmpSynch.FALSE = attribute SmpSynch is not available in the SV buffer.Reserved to ensure backward compatibility to IEC 61850-9-2 Edition 1.0 (sample synchronised). sample-rateBooleanrmTRUE = SV buffer contains the attribute SmpRate.FALSE = attribute SmpRate is not available in the SV buffer. data-set Boolean r m TRUE = SV buffer contains the attribute DatSet.FALSE = attribute DatSet is not available in the SV buffer. securityBoolean r m Mapping specific attribute. TRUE = SV buffer contains the attribute Security. FALSE = attribute Security is not available in the SV buffer. DstAddress See Table 10m Mapping specific attribute. noASDU Integer r m Mapping specific attribute. Number of ASDU concatenated into one APDU.61850-9-2IEC:2005(E) 18 57/800/CD Table 10 - DstAddress structure MMS component nameMMSTypeDescription r/wm/oCondi-tionCommentsAddr OCTET-STRING r m Length is 6 Octets and contains the value of the destination Media Access Control (MAC) address to which the SV message is to be sent.If DstAddress is member of a MSVCB, the address shall be an Ethernet Address that has the multicast bit set to TRUE. IfDstAddressismemberofaUSVCB,the address shallbe the Ethernet Address of the SV subscriber. SeeAnnexCformulticastaddressing recommendationsPRIORITYUnsigned8 r m Range of values shall be limited from 0 to 7.VID Unsigned16 r/wm Range of values shall be limited from 0 to 4095.APPID Unsigned16 r m As defined in 5.3.3. 61850-9-2IEC:2005(E) 19 57/800/CD8.2.2MSV Services See Table 11. Table 11 Mapping of multicast sampled value services Services of MSVCB ClassService SendMSVMessageTransmission of MSV messages is mapped directly on data link layer as defined in 8.4 and 8.5 GetMSVCBValueMapped to MMS read service SetMSVCBValueMapped to MMS write service 8.3Mapping of the unicast sampled value control block class and services 8.3.1Unicast sampled value control block definition Thesampledvaluecontrolblock,asdefinedinIEC 61850-7-2,shallbepre-definedby configurationorshallbemappedtoanMMSUnicastSampledValueControlBlock(USVCB) as defined in Table 12. All USVCB components shall be of the Functional Constraint US. Table 12 MMS TypeDescription definition for USVCB MMS Structure MMS component nameMMS type descriptionr/wm/o Condi-tionCommentsUsvCBNam IdentifierrmMMS Identifier of the structure of the UsvCBName within the MMS object named: LLN0$MV e.g. LLN0$US$ UsvCBRef Visible-stringrmThe value of this component shall contain the IEC Reference of the UsvCB. e.g./LLN0$US$SvEnaBooleanr/wmTRUE = transmission of sampled value buffer is activated. FALSE = transmission of sampled value buffer is deactivated. ResvBooleanr/wmTRUE = USVCB is exclusively reserved for the client that has set this value to TRUE. UsvI D Visible-stringrmSystem-wide unique identification. DatSet Visible-stringrmThe value of this component shall contain the IEC Reference of the DataSet conveyed by the UsvCB.This ObjectReference shall be limited to VMD or Domain scoped NamedVariableLists.ConfRevIntegerrmCount of configuration changes regard to USVCB.SmpRateIntegerrmAmount of samples per nominal periods. OptFldsBitString refresh-timeBooleanr m TRUE = SV buffer contains the attribute RefrTmFALSE = attribute RefrTm is not available in the SV buffer. sample-synchronisedReservedBooleanrmTRUE = SV buffer contains the attribute SmpSynch.FALSE = attribute SmpSynch is not available in the SV buffer.Reserved to ensure backward compatibility to IEC 61850-9-2 Edition 1.0 (sample synchronised). 61850-9-2IEC:2005(E) 20 57/800/CD sample-rateBooleanrmTRUE = SV buffer contains the attribute SmpRate.FALSE = attribute SmpRate is not available in the SV buffer. data-set Boolean r m TRUE = SV buffer contains the attribute DatSet.FALSE = attribute DatSet is not available in the SV buffer. securityBoolean r m Mapping specific attribute. TRUE = SV buffer contains the attribute Security. FALSE = attribute Security is not available in the SV buffer. DstAddress See Table 10m Mapping specific attribute. noASDU Integer r m Mapping specific attribute. Number of ASDU concatenated into one APDU.8.3.2 USV Services See Table 13. Table 13 Mapping of unicast sampled value services Services of USVCB classService SendUSVMessageTransmission of USV messages is mapped directly on data link layer as defined in 8.4 and 8.5 GetUSVCBValueMapped to MMS read service SetUSVCBValueMapped to MMS write service 61850-9-2IEC:2005(E) 21 57/800/CD8.4Mapping of the update of the sampled value buffer As specified in IEC 61850-7-2, the communication system is responsible to update the buffer of the subscriber. Theupdate isdirectlymappedto an ethertype reserved for IEC 61850 applications based on ISO/IEC 8802-3 MAC Sublayer. The communication stack used does not provide the following functionality: Initiatingandcheckingtheupdateofthesampledvaluebufferoverthecommunication link.Optionallyconcatenating theupdateofmore than one buffer into the same link layer frame. This is an application layer functionality. Encoding the abstract data types. This is a presentation layer functionality. Concatenatingtheupdateofmorethanonetransmissionbufferintothesamelinklayer frameasatransportlayerfunctionalityisnotsupported.Theopposite,tosegmentthe updateofonebuffertoseverallinklayerframesisnotconsidered,sincethemaximum frame length of the link layer protocols is sufficient. Translating the logical address of the subscriber in a physical MAC address. Therefore, the additional definitions of 8.5 apply. 8.5Additional definitions for the transmission of sampled values Application layer functionality ThemappingprovidesthecapabilitytoconcatenatemorethanoneASDUintooneAPDUbeforetheAPDUispostedintothetransmissionbuffer.ThenumbersofASDUswhichwillbe concatenatedintooneAPDUareconfigurableandrelatedtothesamplerate.The concatenation of ASDUs is not dynamically changeable in order to reduce the implementation complexity.WhenconcatenatingseveralASDUsintooneframe,theASDUwiththeoldest samples is the first one in the frame. Details are shown in Figure 3. No. of ASDUs (UI16)APDU (Application Protocol Data Unit)ASDU's (Application Service Data Unit)ASDU 1APCI(Application Protocol Control Information)ASDU 2 ASDU n Length TagFigure 3 Concatenation of several ASDU's into one frame ASN.1grammarinrelationwiththeBasicEncodingRules(BER)isusedtoencodethe sampledvaluemessagesfortransmissiononISO/IEC 8802-3.ToguaranteecompatibilitytoIEC 61850-9-1,thefirstASN.1tag(9-1-Pdu)ofthesampledvaluePDUarereservedforthe universaldataset.TheASN.1grammarforthesampledvaluemessagesaredefinedas follows to ensure data consistency to IEC 61850-9-1 and in combination with further sampled value messages as described in this SCSM.IEC 098/0461850-9-2IEC:2005(E) 22 57/800/CD Presentation layer functionality For the transmission, the sampled value buffer is encoded as specified in the Table 14: Table 14 Encoding for the transmission of the sampled value buffer IEC61850 DEFINITIONS ::= BEGIN IMPORTS Data FROM ISO-IEC-9506-2 IEC 61850-9-2 Specific Protocol ::= CHOICE { 9-1-Pdu[0] IMPLICIT OCTET STRING,-- Reserved for 9-1 APDUsavPdu[APPLICATION 0] IMPLICIT SavPdu,Abstract Buffer Format according to I EC 61850-7-2 Coding in I EC 61850-9-2Comments Attribute nameAttribute typeASN.1 Basic Encoding Rules (BER)SavPdu ::=SEQUENCE { noASDU [0] I MPLI CI T I NTEGER (1..65535),Mapping specific attribute. Number of ASDUs, which will be concatenated into one APDU. Securitysecurity [1] ANY OPTI ONAL,Mapping specific attribute. Reserved for future definition (e.g. digital signature). asdu [2] I MPLI CI T SEQUENCE OF ASDU}1 tonumber of ASDUs as specified before. ASDU ::=SEQUENCE { MsvI D or UsvI DVI SI BLE STRI NGsvI D [0] I MPLI CI T VisibleString,Should be a system-wide unique identification.DatSetObjectReferencedatset [1] I MPLI CI T VisibleString OPTI ONAL,Value from the MSVCB or USVCB SmpCntI NT16UsmpCnt [2] I MPLI CI T OCTET STRI NG (SI ZE(2)),Will be incremented each time a new sampling value is taken. The counter shall be set to zero if the sampling is synchronised by clock signal (SmpSynch = TRUE) and the synchronising signal occurs. See NOTE 2. The OCTET STRI NG is interpreted as I NT16U as defined in Table 15ConfRevI NT32UconfRev [3] I MPLI CI T OCTET STRI NG (SI ZE(4)),Value from the MSVCB or USVCB. The OCTET STRI NG is interpreted as I NT32U as defined in Table 15RefrTmEntryTimerefrTm [4] I MPLI CI T UtcTime OPTI ONAL,RefrTm contains the refresh time of the SV buffer. SmpSynch I NT8U smpSynch [5] I MPLI CI T OCTET STRI NG (SI ZE(1)), 2 = SV are synchronised by a global area clock signal. 1 = SV are synchronised by a local area clock signal. 0 = SV are not synchronised by an external clock signal. SmpRateI NT16UsmpRate [6] I MPLI CI T OCTET STRI NG (SI ZE(2)) OPTI ONAL, Value from the MSVCB or USVCB. The OCTET STRI NG is interpreted as I NT16U as defined in Table 15Sample [1..n]Type depends on the CDC defined in I EC 61850-7-3. sample [7] I MPLI CI T OCTET STRI NG (SI ZE(n))}List of data values related to the data set definition. See NOTE 1. NOTE 1 For the encoding of the Data, the rules for the encoding of the basic data types shall apply as defined in Table 14. The SI ZE(n) is the cumulated size of all the data conveyed as defined in the DataSet. NOTE 2 When sync pulses are used to synchronise merging units, the counter shall be set to zero with every sync pulse. The value 0 shall be given to the data set where the sampling of the primary current coincides with the sync pulse. NOTE 3 The usage of the OptFlds attribute according to I EC 61850-7-2 is not necessary, because the relating attributes RefrTm, SmpSynch, security, SmpRate and DatSet will be signed as optional via the ASN.1 attribute directly. ... } END61850-9-2IEC:2005(E) 23 57/800/CDFor the tag definition of basic data types, see 8.6. 8.6Definitions for basic data types Presentation layer functionality Table 15 shows the encoding for the basic data types used for the Data values referenced by the data set members. Table 15 Encoding for the basic data types Data types according to I EC 61850-7-2 Encoding in data setComments BOOLEAN8 Bit set to 0 FALSE; anything else = TRUE I NT88 Bit Big Endiansigned I NT1616 Bit Big Endiansigned I NT3232 Bit Big Endiansigned I NT128128 Bit Big Endiansigned I NT8U8 Bit Big Endianunsigned I NT16U16 Bit Big Endianunsigned I NT24U24 Bit Big Endianunsigned I NT32U32 Bit Big Endianunsigned FLOAT3232 Bit I EEE Floating Point (I EEE 754) FLOAT6464 Bit I EEE Floating Point (I EEE 754) ENUMERATED32 Bit Big Endian CODED ENUM32 Bit Big Endian OCTET STRI NG20 Bytes ASCI IText, Null terminated VI SI BLE STRI NG35 Bytes ASCI IText, Null terminated UNI CODE STRI NG20 Bytes ASCI IText, Null terminated ObjectName20 Bytes ASCI IText, Null terminated ObjectReference20 Bytes ASCI IText, Null terminated TimeStamp64 Bit Timestamp as defined in I EC 61850-8-1 EntryTime48 Bit Timestamp as defined in I EC 61850-8-1 Data types according to I EC 61850-8-1 Encoding in data setComments BI TSTRI NG32 Bit Big Endian 9Conformance 9.1Notation For the following clause, see the abbreviations given in Clause 4. 9.2 PI CS9.2.1Profile conformance Table 16 and Table 17 define the basic conformance statement. 61850-9-2IEC:2005(E) 24 57/800/CD Table 16 PI CS for A-Profile support Client ServerValue/commentF/ S F/ SA1Client/Server A-Profilec1c1Refer to 5.2 A2 SV A-Profilec2c2Refer to 5.3 c1 Shall be m if support for any service specified in Table 1 are declared within the ACSIbasic conformance statement.c2 Shall be m if support for any service specified in Table 4 are declared within the ACSIbasic conformance statement.Table 17 PI CS for T-Profile support Client ServerValue/commentF/S F/ST1TCP/IP T-Profilec1c1 T2 SV T-Profilec2c2 c1 Shall be m if support for A1 is declared. Otherwise, shall be 'i'c2 Shall be 'm'if support for A2 is declared. Otherwise, shall be 'i' .9.2.2 SV Services ThisclausedescribestheProtocolImplementationConformanceStatementforsampled values services based on the IEC 61850-7-2 basic conformance statement. See Table 18. Table 18 SV conformance statement Services Client/subscriberServer/ publisherValue/commentMulticastSendMSVMessage c1c1 GetMSVCBValues c2c2 SetMSVCBValues c3c3 UnicastSendUSVMessage c1c1 GetUSVCBValues c2c2 SetUSVCBValues c3c3 c1 Shall declare m for at least one (MSV or USV) as declared within ACSIbasic conformance statement. c2 Shall be o as declared within ACSIbasic conformance statement. See IEC 61850-8-1, Table 95 Read Conformance Statement. c3 Shall be o as declared within ACSIbasic conformance statement. See IEC 61850-8-1, Table 96 Write Conformance Statement. 61850-9-2IEC:2005(E) 25 57/800/CD10Substation Configuration language (SCL) Conforming implementations shall support the Substation Configuration Language as defined in IEC 61850-6 for exchange between engineering tools. SCSM specific address element definitions ThisClausedefinesthexs:stringtypesthatareallowedfortheSVaddressingastype parametersofthePelementoftheAddresselement.Thevaluesandcharacterrestrictions are defined in Table 19. Table 19 Definitions for SV SCL P-type designationDescription m/o Restrictions/commentsMAC-Address Media Access Address valuemShall be 6 groups of 2 visible characters separated by hyphens(-). Characters shall be limited to 0-9 and A-F. APPI D Application IdentifieroShall be 4 characters. Characters shall be limited to 0 to 9 and A to F. VLAN-PRIORITYVLAN User Priorityc1Shall be a single character.Characters shall be limited to 0 to 7. VLAN-I D VLAN I D oShall be 3 characters. Characters shall be limited to 0 to 9 and A to F. c1 Shall only be present if VLAN is also present. 61850-9-2IEC:2005(E) 26 57/800/CD Annex A(informative)ISO/IEC 8802-3 frame format and ASN.1 basic encoding rules A.1ISO/IEC 8802-3 frame format See Figure A.1. Octets87654321Notes PreambleStart of frame 0 1 2 3 4 5Destination address 6 7 8 9 10 11HeaderMACSource address Refer to Address Fields section. 12 13TPID14 15Priority taggedTCIRefer to Priority Tagging/VirtualLAN section.16 17 Ethertype18LengthStart19 APPID20 21 Length (m + 8) 22 23 Reserved 1 24 25 Reserved 2 26 . m + 26APDU (of length m) Ethertype PDU Refer to Ethertype and Other Header Informationsection.. .1517(Pad bytes if necessary) . . . .1521Frame check sequence Figure A.1 - ISO/IEC 8802-3 frame format IEC 099/04 61850-9-2IEC:2005(E) 27 57/800/CDA.2 ASN.1 Basic Encoding Rules (BER) ASN.1Basicencodingrules(asspecifiedinISO/IEC 8825-1)willbeusedforencodingand decoding of Sampled Values. The main encoding principles are shown as an overview. TheBERtransfersyntaxhastheformatofatripletTLV(Type,Length,Value)or (Tag, Length, Value) as shown in Figure A.2. Allfields(T,L,V)areseriesofoctets.ThevalueVcanbeatripletTLVitself,ifitis constructed.Thetransfersyntaxisoctet-basedandbigendian-oriented.ThelengthfieldLdefinesthe length of each TLV triplet.Tag Length Value Triplet TLVTag Length ValueTag Length ValueTriplet TLVTriplet TLVFigure A.2 - Basic encoding rules format The tag octets correspond to the encoding of the tag of the value type. Figure A.3 shows the two formats of the tag octets T class P/CTag octetBit 7 Bit 0 Bit 6 Bit 5Bit 7 Class Bit 60011UNIVERSALAPPLICATIONcontext-specificPRIVATE0101Bit 5 Format01PrimitiveConstructedFigure A.3 - Format of the tag octets IEC 100/04IEC 101/04 61850-9-2IEC:2005(E) 28 57/800/CD A.3Example for an ASN.1 coded APDU frame structureThe example in Figure A.4 shows the APDU frame structure with 4 concatenated ASDUs. savPdu 60L noASDU 80L4 security81L Sequence of ASDU A2L 30L svI D 80Lvaluesdatset81LvaluessmpCnt82LvaluesconfRev83LvaluesrefrTm84LvaluessmpSynch85LvaluessmpRate86LvaluesSequence of Data87L valuesvaluesvaluesvaluesvaluesvalues DataSetvalues30L ASDU 2 30L ASDU 3 30L ASDU 4 ASN.1 TagL = Length Figure A.4 - Example for an ASN.1 coded APDU frame structure IEC 102/0461850-9-2IEC:2005(E) 29 57/800/CDAnnex B(informative)Process bus architectures Thecommunicationbuscanbearrangedinseveraldifferentways,dependingondataflow requirements, reliability requirements or practicalities during installation.Figure B.1 shows four alternative solutions of the process bus architectures. RRRRR1342Figure B.1 - Alternative process bus architectures Alternative1indicatesacommunicationbusstructurewhereeachbay(installationunit)has itsownprocessbussegment.Toallowforprotectionandcontrolequipmentthatrequires datafrommorethanonesegment,aseparatestation-widecommunicationbusisinstalled, with switches or routers to each bay segment to transmit the required data streams. Alternative2indicatesasimilarstructurebuteachbaysegmentcoversmorethanonebay. Data streams required by more than one segment are transferred by switches or routers. The exampleshowsdatafromthebusbarvoltagetransformerbeingusedbydirectionalearth-fault relays on all bays. Alternative3indicatesasinglestation-widecommunicationsbus,towhichalldevicesare connected.Thisrequiresaveryhighdatarateonthebus,buteliminatestheneedfor routers.Alternative4indicatesafunctionorientedbusstructure.Inthiscasethebussegmentsare set up to correspond to protection zones. Although routers are required, the segments can be arranged to minimize the data to be transferred between segments. Theprocessbushastobeconsideredasasubstationentitywithdefinedinterfaces.The processbusmaythereforehavepropertiessuchasreliabilityandperformancethatare reflectedontheinterfacecharacteristics.Thepropertieswillbeincludedinthesubstation design/integration,forexampleinreliabilityandperformancecalculations,asanyother entity.The processbusentitymay,andwill,compriseseveralpartsthatvarybyvendorand implementation.IEC 103/04 61850-9-2IEC:2005(E) 30 57/800/CD Asaconsequenceofthismodel,theprocessbusmaybeasingle'entity'ordividedinto several'entities'thatmaybeinterconnectedorchained.Thecharacteristicsoftheprocess bus 'entity' will depend on the realization (one or many process busses, etc.). 61850-9-2IEC:2005(E) 31 57/800/CDAnnex C(informative)Multicast address selection Inordertoincreasetheoverallperformanceofmulticastmessagereception(forexample GOOSE, GSSE,andSampledValues),itispreferabletohavetheMediaAccessController (MAC)hardwareperformthefiltering.Thehashalgorithmsinthevariousintegratedcircuits dovary.Itisrecommended,asasystemintegrator,toevaluatetheimpactofthese algorithms when assigning destination multicast addresses. VendorsofIEC 61850-8-1orIEC 61850-9-2implementationsthatsendthesetypesof messagesshouldproviderecommendationsofaddressingbasedupontheMACICshash algorithms. One such recommendation might appear as follows: Themulticastaddresses(octetstringofsize6)usedwithinthisstandardwillhavethe structure: The first three octets are assigned by IEEE with 01-0C-CD. The fourth octet will be 01 for GOOSE, 02 for GSSE, and 04 for multicast sampled values. Thelasttwooctetswillbeusedasindividualaddressesassignedbyrangedefinedin Table C.1. Table C.1 Recommended multicast addressing example Recommended address range assignments Service Starting address(hexadecimal)Ending address (hexadecimal)GOOSE 01-0C-CD-01-00-0001-0C-CD-01-01-FF GSSE 01-0C-CD-02-00-0001-0C-CD-02-01-FF Multicast sampled values01-0C-CD-04-00-0001-0C-CD-04-01-FF ___________