【英文标准名称】:Copper-Zinc-Lead(LeadedRedBrassorHardwareBronze)Rod,BarsandShapes
【原文标准名称】:铜锌铅合金(含铅红铜或器具青铜)条材、棒材和型材
【标准号】:ASTMB140-1992
【标准状态】:作废
【国别】:美国
【发布日期】:1992
【实施或试行日期】:
【发布单位】:美国材料与试验协会(ASTM)
【起草单位】:ASTM
【标准类型】:()
【标准水平】:()
【中文主题词】:条材;合金;棒材;配件;铅;铜;黄铜;有色金属;有色金属;锌;铜合金;青铜
【英文主题词】:copper;alloys;copperalloys;zinc;rods;lead;bronzes;bars(materials);brass;non-ferrousmetals;fittings;nonferrousmetals
【摘要】:
【中国标准分类号】:H62
【国际标准分类号】:77_120_30
【页数】:2P;A4
【正文语种】:英语


【英文标准名称】:Informationtechnology-FibreDistributedDataInterface(FDDI)-Part8:MediaAccessControl-2(MAC-2)
【原文标准名称】:信息技术.光纤分布式数据接口(FDDI).第8部分:媒体访问控制-2(MAC-2)
【标准号】:ISO/IEC9314-8-1998
【标准状态】:现行
【国别】:国际
【发布日期】:1998-08
【实施或试行日期】:
【发布单位】:国际标准化组织(ISO)
【起草单位】:ISO/IECJTC1
【标准类型】:()
【标准水平】:()
【中文主题词】:光波导;界面;数据传输;光学纤维;信息技术;网络互连;定义;数据处理;通信规程;光纤分布数据接口(FIBERDISTRIBUTEDDATAINTERFACE);信息交换;数据接口;令牌环;控制规程;接口(数据处理);多路存取计算机
【英文主题词】:
【摘要】:ThispartofISO/IEC9314specifiestheMediaAccessControl(MAC),themiddlesublayeroftheDataLinkLayer(DLL),forFibreDistributedDataInterface(FDDI).FDDI(ISO/IEC9314)providesahigh-bandwidth(100Mbit/s),general-purposeinterconnectionamonginformationprocessingsystems,subsystemsandperipheralequipment,usingfibreopticsorothertransmissionmedia.FDDIcanbeconfiguredtosupportasustaineddatatransferrateofatleast80Mbit/s(10Mbyte/s).FDDIprovidesconnectivityformanynodesdistributedoverdistancesofmanykilometresinextent.CertaindefaultparametervaluesforFDDI(e.g.timersettings)arecalculatedonthebasisofupto1000transmissionlinksorupto200kmtotalfibrepathlength(typicallycorrespondingto500nodesand100kmofdualfibrecable,respectively);however,theFDDIprotocolscansupportmuchlargernetworksbyincreasingtheseparametervalues.Asshowninfigure1,ISO/IEC9314consistsofa)APhysicalLayer(PL),whichisdividedintotwosublayers:1)APhysicalMediumDependent(PMD),whichprovidesthedigitalbasebandpoint-to-pointcommunicationbetweennodesintheFDDInetwork.ThePMDprovidesallservicesnecessarytotransportasuitablycodeddigitalbitstreamfromnodetonode.ThePMDdefinesandcharacterizesthefibre-opticdriversandreceivers,medium-dependentcoderequirements,cables,connectors,powerbudgets,opticalbypassprovisions,andphysical-hardware-relatedcharacteristics.ItspecifiesthepointofinterconnectabilityforconformingFDDIattachments.TheinitialPMDstandard,ISO/IEC9314-3,definesattachmenttomulti-modefibre.AdditionalPMDsublayerstandardsarebeingdevelopedforattachmenttosingle-modefibreandSONET.2)APhysicalLayerProtocol(PHY),whichprovidesconnectionbetweenthePMDandtheDataLinkLayer.PHYestablishesclocksynchronizationwiththeupstreamcode-bitdatastreamanddecodesthisincomingcode-bitstreamintoanequivalentsymbolstreamforusebythehigherlayers.PHYprovidesencodinganddecodingbetweendataandcontrolindicatorsymbolsandcodebits,mediumconditioningandinitializing,thesynchronizationofincomingandoutgoingcode-bitclocks,andthedelineationofoctetboundariesasrequiredforthetransmissionofinformationtoorfromhigherlayers.InformationtobetransmittedonthemediumisencodedbythePHYusingagrouptransmissioncode.b)ADataLinkLayer(DLL),whichisdividedintotwoormoresublayers:1)AnoptionalHybridRingControl(HRC),whichprovidesmultiplexingofpacketandcircuitswitcheddataonthesharedFDDImedium.HRCcomprisestwointernalcomponents,aHybridMultiplexer(H-MUX)andanisochronousMAC(I-MAC).H-MUXmaintainsasynchronous125uscyclestructureandmultiplexesthepacketandcircuitswitcheddatastreams,andI-MACprovidesaccesstocircuitswitchedchannels.2)AMediaAccessControl(MAC),whichprovidesfairanddeterministicaccesstothemedium,addressrecognition,andgenerationandverificationofframechecksequences.Itsprimaryfunctionisthedeliveryofpacketdata,includingframegeneration,repetition,andremoval.ThedefinitionofMACiscontainedinthispartofISO/IEC9314.3)AnoptionalLogicalLinkControl(LLC),whichprovidesacommonprotocolforanyrequiredpacketdataadaptationservicesbetweenMACandtheNetworkLayer.LLCisnotspecifiedbyFDDI.4)AnoptionalCircuitSwitchingMultiplexer(CS-MUX),whichprovidesacommonprotocolforanyrequiredcircuitdataadaptationservicesbetweenI-MACandtheNetworkLayer.CS-MUXisnotspecifiedbyFDDI.c)AStationManagement(SMT),whichprovidesthecontrolnecessaryatthenodeleveltomanagetheprocessesunderwayinthevariousFDDIlayerssuchthatanodemayworkcooperativelyonaring.SMTprovidesservicessuchascontrolofconfigurationmanagement,faultisolationandrecovery,andscheduling
【中国标准分类号】:M33
【国际标准分类号】:33_180_01;35_110
【页数】:98P;A4
【正文语种】:英语