以太网OAM协议解析及测试关注点

以太网OAM（802.3ah）协议分析及测试关注点DOCUMENTID:PRODUCT:RELEASE:2.0FEATURE:SUBSYSTEM:DISTRIBUTETO:1 以太网OAM简介 22 以太网OAM在网络上的应用 23 OAMPDU报文解析及工作原理 2 报文解析 2 几种最常见的OAMPDU用法： 2 InformationOAMPDU 2 EventNotificationOAMPDU 2 LoopbackControlOAMPDU 2 以太网OAM工作原理： 2 建立以太网OAM连接： 2 链路监控 2 远端故障检测 2 远端环回 24 Featurelist 2 主要功能 2 工作原理 2 EventNotification的处理 2 OAMPDU报文 2 LocalInformationTLVs 2 RemoteInformationTLVs 2 LinkEventTLVs 2 VariablesDescriptorsandContainers 25 测试关注点： 2 概述： 2 具体测试点： 2

以太网OAM简介以太网OAM（Operations,AdministrationandMaintenance，操作、管理和维护）是一种监控网络问题的工具。它工作在数据链路层，利用设备之间定时交互OAMPDU（OAMProtocolDataUnits，OAM协议数据单元）来报告网络的状态，使网络管理员能够更有效地管理网络。以太网OAM在网络上的应用随着数据业务的广泛应用，以太网在通信网络中扮演着越来越重要的作用，但是以太网与传统的SDH相比，在网络故障告警、链路质量、维护手段等方面都略逊一筹。于是国际标准化组织IEEE，先后推出了802.3ah(2004)和802.1ag(2007)两个标准化协议来强化以太网在维护、告警方面的能力。是偏网络和应用的OAM，主要用在汇聚层和核心层上，它的OAMPDU报文能够传输多跳。它不仅能够监测链路质量、收集告警，还能够实现电信级快速倒换以及traceroute、ping等功能。在TN705/725上的MPLSOAM就部分参考了802.1ag的协议，大家有兴趣可以仔细研究下。由于TN703产品主要定位于接入网络边缘，因而目前只要求支持802.3ah的以太网OAM即可。802.3ah以太网OAM最主要的功能主要有三个方面，分别是：1、链路性能监测：可以对链路故障进行检测；2、故障侦测和告警：可以在链路出现故障时及时通知网络管理员；3、环路测试：通过将非OAMPDU环回来检测链路故障。注：下文中“以太网OAM”如未特殊标明，均指802.3ah的以太网OAM。OAMPDU报文解析及工作原理报文解析几个重要字段的含义如下：。Destaddr：以太网OAM报文的目的MAC地址，为组播MAC地址0180c2000002。。Sourceaddr：以太网OAM报文的源MAC地址，为发送端的桥MAC地址，该地址是一个单播MAC地址。。Type：以太网OAM报文的协议类型，为0x8809。。Subtype：以太网OAM报文的协议子类型，为0x03。。Flags：Flags域，包含了以太网OAM实体的状态信息。。Code：本字段指明了OAMPDU的报文类型。0x00表示InformationOAMPDU、0x01表示EventNotificationOAMPDU、0x04表示LoopbackControlOAMPDU

Flags域：主要用来标示链路的故障信息：值得注意的是对于CriticalEvent,DyingGasp,andLinkFault这些链路告警的具体定义，在802.3ah协议中是没有注明的。这可能要厂家根据需要自行定义。几种最常见的OAMPDU用法：在ETHOAM中最常见的三种OAMPDU报文分别是InformationOAMPDU、EventNotificationOAMPDU和LoopbackControlOAMPDU，下面将分别加以介绍：InformationOAMPDU用于将以太网OAM实体的状态信息（包括本地信息、远端信息和自定义信息）发给远端的以太网OAM实体，保持以太网OAM连接。具体的报文结构形式：EventNotificationOAMPDU（事件通知OAMPDU）一般用于链路监控，是用于对连接本端和远端以太网OAM实体的链路发生的故障进行告警。具体的报文格式：LoopbackControlOAMPDU（环路控制OAMPDU）报文主要用于远端环回控制。环回控制OAMPDU报文用来控制远端设备的OAM环回状态，该报文中带有使能或去使能环回功能的信息，根据该信息开启或关闭远端环回功能。具体的报文格式：以太网OAM工作原理：建立以太网OAM连接：以太网OAM连接过程也称作Discovery阶段，本阶段是OAM实体发现远端设备的OAM实体，并与之建立稳定对话的过程。在这个阶段中，相连的以太网OAM实体（即使能OAM功能的端口）通过交互InformationOAMPDU向对端通报各自的以太网OAM配置信息及本地节点支持的以太网OAM能力信息。OAM实体收到对端配置参数后，决定是否同意建立OAM连接，如果两端的以太网OAM对Loopback功能、单向链路检测及链路事件的配置都通过检查时，以太网OAM协议将在链路层开始正常工作。我们可以选择两种模式来进行以太网OAM的连接：主动模式和被动模式两种模式下的设备处理能力如下表所示：处理能力主动模式被动模式初始化以太网OAMDiscovery过程可以不可以对以太网OAMDiscovery初始化过程的响应可以可以发送InformationOAMPDU可以可以发送EventNotificationOAMPDU可以可以发送不携带TLV的InformationOAMPDU可以可以发送LoopbackControlOAMPDU可以不可以对LoopbackControlOAMPDU的响应可以，但需要对端也处于主动模式下可以发送组织指定的OAMPDU可以可以发送VariableRequestOAMPDUs可以不可以发送VariableResponseOAMPDUs可以可以发送带团队属性的特殊OAMPDUs可以可以当然在两个peertopeer的端口上，都配置成active端口也是可以的。以太网OAM连接建立后，两端的OAM实体通过发送InformationOAMPDU保持连接。若在5秒钟内没有收到对端OAM实体的InformationOAMPDU，则认为连接超时，需要重新建立OAM连接。链路监控链路监控用于检测和发现链路层的故障。以太网OAM利用EventNotificationOAMPDU的交互来进行链路监控。当链路故障发生时，本地链路监控到故障后，将向对端以太网OAM实体发送EventNotificationOAMPDU，通报一般链路事件。我们可以通过观察日志信息动态地掌握网络的状况。一般链路事件的定义如下：一般链路事件定义错误信号事件单位时间内的错误信号数量超过定义的阈值错误帧事件单位时间内的错误帧数量超过定义的阈值错误帧周期事件指定帧数N为周期，在收到N个帧的周期内错误帧数超过定义的阈值错误帧秒数事件指定M秒数下有错误帧的秒数超过了定义的阈值（错误帧秒的定义：在某一秒内发生了错误帧，则该秒为错误帧秒）

远端故障检测OAMPDU定义了一个标志（Flag域）允许以太网OAM实体把该故障信息传送给对端。该标志可以表示下列紧急链路事件：.链路故障（LinkFault）：对端链路信号丢失。.致命故障（DyingGasp）：不可预知的状态发生，比如电源中断。.紧急事件（CriticalEvent）：不能确定的紧急事件发生。以太网OAM连接过程中是不断的发送InformationOAMPDU的，本端OAM实体可以将本端发生的紧急链路事件信息通过InformationOAMPDU告诉远端OAM实体。当A与B之间的链路有一条发生故障时，B设备就会立即将含有链路故障信息的OAMPDU报文通过另一条链路发送给A。这样，可以通过观察日志信息动态地了解链路的状态，对相应的错误及时进行处理。需要注意的是远端的故障监测只能工作在双发双收的链路上，即双向链路中有一条失效，另一条还继续工作的那种情况。

远端环回LoopbackOAMPDU的底层转发流程：远端环回只有在以太网OAM连接建立完成后才能实现。在连接建立的情况下，主动模式的OAM实体发起远端环回命令，对端实体对该命令进行响应。当远端处于环回模式下，除了OAMPDU报文以外的所有报文都将按照原路返回，而OAMPDU报文将继续上送至被环回设备的CPU进行处理。通过进行环回检测可以及时发现网络故障，并通过分段环回检测来帮助定位故障发生的具体区域。Featurelist主要功能tmeaueSublaselu/CmmntSppotOOAMobetcas036MustCSIOAMcinterieitracs725MustSnenalsevcenefae72MustACAtvemo72MustASasiemod72MustLOAMremteopba721ble7–8MustUNIUiieconloprton7212,ble7–8ReqiesupprtforundrcioalpeainasdeiednCluse6.MustEVNTinkEens743.,75MustARaraleRtival743.,743.MayOOgaiatonSeciOAMPDU743.MayOEOgaiatonSecicEens753.5MayOIOgaiatonSecicnomtonT752.May工作原理ItemFeatureSubclausealue/CommentSupportOFS1Passivemodelimitedtransmission57CannotsendariableRequestorLoopbackControlOAMPDUsMustOFS2Discoverystatediagram57ImplementedasdefinedinFigure57–5MustOFS3ransmitstatediagram57ImplementedasdefinedinFigure57–6MustOFS4OAMPDUtransmissionwhenlocal_pduissettoLF_INFO57OnlyInformationOAMPDUswithLinkFaultbitofFlagsfieldandwithoutInformationTVscanbetransmittedMustOFS5OAMPDUtransmissionwhenlocal_pduissettoRX_INFO57NoOAMPDUtransmissionallowedMustOFS6OAMPDUtransmissionwhenlocal_pduissettoINFO57OnlyInformationOAMPDUscanbetransmittedMustOFS7OFS8OAMPDUtransmissionwhenlocal_pduissettoAN:OAequestserviceprimitivewithoneormorecriticallinkeventparametersOAquestserviceprimitive5757RequeststransmissionofInformationOAMPDUwithappropriatebitsofFlagsfieldsetRequeststransmissionofOAMPDUMustOFS9OFS10OAMPDUFlagsfieldreservedencodingsRemotetableandRemoteEvaluatingbitsLocaltableandLocalEval-uatingbitsable57–3able57–3Encodingof0x3isnottransmittedEncodingof0x3isnottransmittedMustOFS1Reservedbitsable57–3ReservedbitsarezeroontransmissionMustOFS12OAMPDUCodefield57OnlydefinedCodefieldvaluesarepermittedintransmittedOAMP-DUsMustOFS13OAMPDUreceptionwhenlocal_pduisnotsettoANY57OnlyInformationOAMPDUsaresenttoOAMcliententityMustOFS14OAMPDUreceptionwhenlocal_pduissettoANY57AllOAMPDUsaresenttoOAMcliententityMustOFS15Multiplexerstatediagram57ImplementedasdefinedinFigure57–7MustOFS16Multiplexertransparentpass-through57Providetransparentpass-throughofframesfromsuperiorsublayertosubordinatesublayerMustOFS17EffectofOAMPDUonaframealreadysubmittedtosubordinatesublayer57HasnoeffectMustOFS18Parserstatediagram57ImplementedasdefinedinFigure57–8MustEventNotification的处理ItemFeatureSubclauseValue/CommentSupportEV1ResponsetoCriticalEventsSet/clearFlagbitsbasedonOAM_CTL.requestserviceprimitiveMustEV2CriticalEventreceptionIndicatedviaFlagsfieldofOAMPDU.indicationserviceprimitiveMustEV3LinkEventreceptionIndicatedviaOAMPDU.indicationserviceprimitivewithallreceivedEventNotificationOAMPDUsMust

OAMPDU报文ItemFeatureSubclausealue/CommentSupportPDU1TaggingOAMPDUscannotbetaggedMustPDU2OAMPDUstructureAsdefinedinFigure57–9andfielddefinitionsMustPDU3MinimumOAMPDUsizeSupportOAMPDUsminFrame-SizeinlengthMustPDU4InformationOAMPDUframestructureShowninFigure57–10MustPDU5InformationOAMPDUwhenlocal_pdusettoLF_INFODatafieldcontainszeroInformationTLVsMustPDU6PDU7InformationOAMPDUwhenlocal_pdunotsettoLF_INFOremote_state_valid=FALSEremote_state_valid=TRUEDatafieldcontainsLocalInformationTLVDatafieldcontainsLocalandRemoteInformationTLVsMustPDU8Typevalues0x03-0xFDTable57–6NottobesentMustPDU9Typevalue0xFFTable57–6NottobesentMustPDU10EventNotificationOAMPDUframestructureShowninFigure57–11MustPDU11EventNotificationOAMPDUSequenceNumberThefirsttwobytesoftheDatafieldcontainaSequenceNumberencodedasanunsigned16-bitintegerMustPDU12EventNotificationOAMPDUEvent(s)DatafieldcontainingoneormoreLinkEventTLVsfollowingtheSequenceNumberMustPDU13VariableRequestOAMPDUframestructureShowninFigure57–12MayPDU14VariableRequestOAMPDUDatafieldDatafieldcontainsoneormoreVariableDescriptorsMayPDU15VariableResponseOAMPDUframestructureShowninFigure57–13MayPDU16VariableResponseOAMPDUDatafieldDatafieldcontainsoneormoreVariableContainersMayPDU17LoopbackControlOAMPDUframestructureShowninFigure57–14MustPDU18LoopbackControlOAMPDUDatafieldDatafieldcontainsasingleOAMRemoteLoopbackcommandfromTable57–5.MustPDU19Commandvalue0x00Table57–5NottobesentMustPDU20Commandvalues0x03-0xFFTable57–5NottobesentMustPDU21OrganizationSpecificOAMPDUframestructureShowninFigure57–15MayPDU22OrganizationSpecificOAMPDUOrganizationallyUniqueIdentifierfieldContains24-bitOrganizationallyUniqueIdentifierMayLocalInformationTLVstemFetueSubluselu/CmmntSupprtLTLcalInomaionT5...Cotistefoowigfedsnormtonyp,normtonLngh,OAMeson,Rviin,ae,OAMCofguaon,OAMPDUCofguaon,OU,ndorSecicnfrmaonMustLT2LcalInomaionTVOAMrine5...1Cotis0x01ocamompinceotipeiiainMustLT3LcalInomaionTVRev-inil5...1atstzroadinrmenedachimeaLcalInomaionTVedhage.MustLT4LcalIn5...1Asefndinabe5–7MustLT5LcalInomaionTVSaeild5...1snottanmitdMustLT6Rsevdbisale5–7RsevdisaezroonrnsmsiMustLT7LcalInomaionTVOAMCnfguaonfed5...1Asefndinabe5–8MustLT8Rsevdbisale5–8RsevdisaezroonrnsmsiMustLT9LcalInomaionTVOAMPDUConiurtonild5...1Asefndinabe5–9MustLT10LcalInomaionTVOUIil5...1Asefndinabe5–10MustLT1Rsevdbisale5–9RsevdisaezroonrnsmsiMustLT12LcalnfrmaonVndrSecicInfrmtoned5...1Asefndinabe5–1Must

RemoteInformationTLVstemFetueSubluselu/CmmntSupprtRT1RmtenormtonTV5...2CotisteIfomainpeildpeiyngteRemoenormtonTVyevauendalrmanngfedsreopedromtelsteevedLcalInomaionTVfomemoeOAMper LinkEventTLVsIemFetueSubluselu/CmmntSppotET1EroedymbolPeidEvntTVsucue57531Conansheolowngild:Evntyp,EvntLngh,Evntmetmp,ErreSymblndo,ErredSymblThehod,ErrdSymbl,ErorRunnngoa,EvntRunigtlMustET2EroedFameEvntTVsrctre57532Conansheolowngild:Evntyp,EvntLngh,Evntmetmp,ErreFrmeido,EroedFameThesod,Errdrms,ErorRnnngoa,EvntRuningoalMustET3EroedFamePeodEvntTVsucue57533Conansheolowngild:Evntyp,Evntngh,Evntmetmp,ErreFrmeido,EroedameThesod,ErrdFrm,ErorRnnngoa,EvntRuningoalMustET4EroedFameSeonsSummayEvetTVsrctre57534Conansheolowngild:Evntyp,EvntLngh,Evntmetmp,ErreFrmeSeondsSummayido,EroedFameSeondsSummayThrsol,EroedFameSconsSumma,ErrRnnngoa,EvntRunigtlMustET5OgniainSpeiicventTVsucue57535Conansheolowngild:Evntyp,EvntLngh,OgniainalyUiqeIenii,OgniainSecfcauMustET6OgniainpeiicventOgniainalyUiqeIeniirie57535Conans2-itOgniainalyUiqeIeniirMustET7pevles0050xFDbe57–2NotobesntMustET8pevle0xFFbe57–2NotobesntMustVariablesDescriptorsandContainers（主要用于mib管理）tmFaueSubluseaueCommentSppotAR1araleDscptrsrcure5761Asdeiedinale7–13MayARARaraleDscptr/rabeBacheeenestrbueoesoteeeneacins57615761Ifnbectorpckgesreeene,onyatbuescanbeondwihnaibleConanerAtosaenotoudinaialeCnaiesMayAR4araleCntiertucueornatiut5762Asdeiedinale7–14MayARARaraleCntier/aralBacheeenestrbueoesoteeeneacins57625762Ifnbectorpckgesreeene,onyatbuescanbeondwihnaibleConanerAtosaenotoudinaialeCnaiesMayAR7yevauex00abe5716NtoesntMayAR8yevaus0x0-x1Fabe5716NtoesntMayAR9yevaus0x2-x2Fabe5716NtoesntMayAR0yevaus0x4-x5Fabe5716NtoesntMayAR1yevaus0x6-x7Fabe5716NtoesntMay测试关注点：概述：由于ETHOAM是TN703产品新增的协议模块，有关协议一致性的测试将通过IXIA的协议测试套来进行，以保证和标准协议的一致性。测试这边将从以下几个部分进行测试：协议一致性测试：OAMPDU报文一致性测试协议状态机测试功能测试：故障监测链路监测远端环回功能组合测试：与mac层的组合测试与lacp的组合测试与流控的组合测试性能规格测试：多端口同时启用大流量情况测试组网应用测试复杂流量测试长时间老化测试异常及攻击测试异常操作异常攻击具体测试点：NmberAssrtionReferenceSetup/rificationss11AMPDUsraerseasilelik,bigssdbetweenpeerOAMentities,andassuch,arentforwardedbyMACcliens(e.g.,bridgesorswitches).IEEE004Section57.1.1,12AmechanismisprovidedtoindicatetoapeerthatthereceiveathofthelocalDTEisnon-opera-iaIEEE004Section57.1.2,SummaryofObjectivesandarne13AMremoteloopbackisanintrusiveoperationthatprevensalinkfromssingfraesbetweentheMACclientofthelocalDTEandtheMACclientoftheremoteDTE.IEEESection,FrameLossDuringOAMRemoteLoopback.14heOAMclientdoesnotrespondtoilleglrequesssuchasariableRequestandLoopbackControlOAMPDUsfromPassiveDTEs.(Note:DUTasactiveshouldnotrespondtoriableRequestOAMPDUsfromssiveANVL).IEEE004Section57.2.4,Page188,ResponsiilitiesofOAMClien.IEEEStd802.3ah-2004Section57.2.4,Page188,ResponsibilitiesofOAMClient.IEEEStd802.3ah-2004Section,Page195,ActiveMode.IEEEStd802.3ah-2004Section,Page195,PassiveMode.IEEEStd802.3ah-2004Section,Page195,PassiveMode.IEEEStd802.3ah-2004Section,Page195,PassiveMode.Fntoalpcfitins21tisticsfromboththelocalandremoteDTEcanbequeriedandcomaredataytimewhiletheremoteDTEisinOAMremoteloopbackode.IEEESection57.2.1,Page196,OAMRemoteLoopback.22hsequeriscankeplacebefore,duringoraterloopbackfraeshavebeensenttotheremoteDTE.IEEESection57.2.1,Page196,OAMRemoteLoopback.23AterreceivingtheLoopbackControlOAMPDU,theremoteAMclientfirstsesislocal_ar_actionrametertoLBandislocal_mux_actionrametertoDISCARDviatheOAuestserviceprimitive,andthensendsanInformaionOAMPDUwithupdatedsateinformationrefletingislocal_a_actionsettoLBandislocal_mux_ationrametersettoDSCARD.IEEESection,Page196,InitiatingOAMRemoteLoop-back.24fanOAMclienthassentaLoopbackConrolOAMPDUandiswaitingforthepeerDTEtorespondwithanInformationOAMPDUthatindi-catesitisinAMremoteloopbackmod,andthatOAMclientreceivesanOAMremoteloopbackcom-mandfromthepeerdevice,thefollowingproce-duresarerecommended:a)IfthelcalDTEhsahighersource_addresthanthepee,itshouldenterOAMremoteloopbackmodeatthecommandofispee.IEEESection,Page196,InitiatingOAMRemoteLoop-back.IEEEStd802.3ah-2004Section,Page196,InitiatingOAMRemoteLoop-back.IEEEStd802.3ah-2004Section,Page196,DuringOAMRemoteLoopback.IEEEStd802.3ah-2004Section,Page196,ExitingOAMRemoteLoopback.IEEEStd802.3ah-2004Section,Page198,TimingConsiderationsforOAMRemoteLoopback.IEEEStd802.3ah-2004Section,Page198,TimingConsiderationsforOAMRemoteLoopback.IEEEStd802.3ah-2004Section,Page198,TimingConsiderationsforOAMRemoteLoopback.IEEEStd802.3ah-2004Section57.2.12,Page198,UnidirectionalOAMOperation.DiledFunctiosandateDiagrams31nethelcalDTEhasreceivedanInformationOAMPDUwiththeLocalInformationTVfromtheremoteDTE,thelcalDTEeinssnigIfrm-tionOAMPDUsthatconainboththeLocalandtenoainIEEESection,Page203,OAMDisco32fheAMlclDTEisinfultsaeaditiscni-uredasactiveentit,itwillsendiformationOAMP-DUsthatonlyconainLocalInformationT.IEEESection,Page203,OAMDisco33fheAMlclDTEisinfultsaeaditiscni-uredasssiveentit,itwillwaitforiformationOAMPDUsthatolyconainLocalInformationT.Withotwhichitcannotcompletediscoveryprocess.IEEESection,Page203,OAMDisco34hileintheAIT_FOR_Xsae,ifthepdu_timerexpiresandoneormoreOAMPDUshavebeensentwithinthelastseond,theransmitprocesstransitionstotheRESETsate.(Note:Checkingtrasitiontriggeredbypdu_timer_done*pdu_cnt!=10).IEEESection,Page205,ransmitateDiagram.35f,howeve,inheAI_OR_TXsate,thepdu_timerexpiresandnoOAMPDUshavebeensentwithinthelastseondandthereisnovalidrequesttosendanOAMPDUpresent,theasmitprocesstransiionstotheTX_OAMPDUsaesend-inganInformationOAMPDU.ThisprevensheDis-coveryprocessfromresarting.IEEEd802.3ah-2004Section,Page205,ransmitateDiagram.36fintheAIT_FOR_TXsate,local_pduissettoLF_INFO,theransmitprocessesurestheInfor-mationOAMPDUhastheLinkFaultbitoftheFlagsfieldsetandhasnoInformationTVsintheDaaiIEEESection,Page205,ransmitateDiagramIEEEahection.6,Page206asmitRules.37fintheAIT_FOR_TXsate,howee,theOAMsublayeretityisconfiguedtonotsendanyOAMPDUs,asindicatedbythelocal_pduvariablesettoRX_INO,theransmitfunctionwillsimplyresartthepdu_timerbyreturningtotheRESETsae.(Note:Checkingtransitiontriggeredbypdu_timer_done*lcal_pdu=RX_INF).IEEESection,Page205,ransmitateDiagram.41Reservedbis(157)shallbesettozerowhensend-inganOAMPDU,andshouldbeignoredonrecep-tionforcomaiilitywithfutureuseofreservedsoe:ecigtDUTshouldnotsendFlagswiththereservedbisseswithDUTactingasPassiveOAMDTE).IEEESection,Page210,FlagsField.Reservedbits(15:7)shallbesettozerowhensend-inganOAMPDU,andshouldbeignoredonrecep-tionforcompatibilitywithfutureuseofreservedbits.(Note:CheckingthatDUTshouldnotsendFlagswiththereservedbitsset,withDUTactingasActiveOAMDTE).IEEEStd802.3ah-2004Section,Page210,FlagsField.LocalStableandLocalEvaluatingformatwo-bit(4:3)encodingshownbelow:0x1=LocalDTEDis-coveryprocesshasnotcompleted.0x2=LocalDTEDiscoveryprocesshascompleted.0x3=Reserved.Thisvalueshallnotbesent.Ifthevalue0x3isreceived,itshouldbeignoredandnotchangethelastreceivedvalue.IEEEStd802.3ah-2004Section,Page211,FlagsField.CriticalEventbitsofFlagfieldsencodingshownbelow:1=Acriticaleventhasoccurred.0=Acriticaleventhasnotoccurred.IEEEStd802.3ah-2004Section,Page211,FlagsField.DyingGaspbitofflagfieldencodingshownbelow:1=Anunrecoverablelocalfailureconditionhasoccurred.0=Anunrecoverablelocalfailurecondi-tionhasnotoccurred.IEEEStd802.3ah-2004Section,Page211,FlagsField.LinkFaultbitofflagfieldencodingshownbelow:1=Localdevice'sreceivepathhasnotdetectedafault.IEEEStd802.3ah-2004Section,Page211,FlagsField.TheoptionalEventNotificationOAMPDU,identifiedwiththeCodefieldsetto0x01,isusedtoalerttheremoteDTEoflinkevents.IEEEStd802.3ah-2004Section,Page212,EventNotificationOAMPDU.AparticularEventNotificationOAMPDUmaybesentmultipletimeswiththesamesequencenum-ber.ANDAnyduplicateEventNotificationOAMP-DUsfollowitsoriginalwithoutadifferent,interveningEventNotificationOAMPDU.IEEEStd802.3ah-2004Section,Page213,EventNotificationOAMPDU.TheOAMclientincrementstheSequenceNumberforeachuniqueEventNotificationOAMPDUformedbytheOAMclient.IEEEStd802.3ah-2004Section,Page212,EventNotificationOAMPDU.TheoptionalVariableResponseOAMPDU,identi-fiedwiththeCodefieldof0x03,isusedtoreturnoneormoreMIBvariables.IEEEStd802.3ah-2004Section,Page214,VariableResponseOAMPDU.AVariableResponseOAMPDUneedstobesentbytheOAMclientwithinonesecondofreceiptofaVariableRequestOAMPDU.IEEEStd802.3ah-2004Section,Page214,VariableResponseOAMPDU.IfaDTEisunabletoretrieveoneormorevariables,itneedstorespondwithinonesecondandindicatetheappropriateerror(s).(Note:ANVLisrequestingaOAMRemoteStatebeforediscovery).IEEEStd802.3ah-2004Section,Page214,VariableResponseOAMPDU.IfaDTEisunabletoretrieveoneormoreattributeswithinapackageorobject,itneedstoeither:a)returntheappropriateVariableIndicationforthepar-ticular attribute(s)andreturnallotherrequestedvariablesorb)returnaVariableIndicationfortheentirepackageorobject.ANDAttributeswithinpackagesandobjectsarereturnedintheorderthoseattributesarelisted.IEEEStd802.3ah-2004Section,Page214,VariableResponseOAMPDUIEEEStd802.3ah-2004Section,Page226,FormatofVariableContainersWhenReturningPackagesandObjects.TheoptionalLoopbackControlOAMPDU,identifiedwiththeCodefieldsetto0x04,isusedtocontroltheremoteDTE'sOAMremoteloopbackstate.IEEEStd802.3ah-2004Section,Page214,LoopbackControlOAMPDU.Value0x00forLoopbackControlOAMPDUcom-mandisreserved-shallnotbetransmitted,shouldbeignoredonreceptionbyOAMclient.(Note:TestforDUTshouldnottransmitLoopbackControlOAMPDUCommandwithValue0x00).IEEEStd802.3ah-2004Section,Page215,LoopbackControlOAMPDU.Value0x03-0xFFforLoopbackControlOAMPDUcommandisreserved-shallnotbetransmitted,shouldbeignoredonreceptionbyOAMclient.(Note:TestforDUTshouldnottransmitLoopbackControlOAMPDUCommandwithvaluesgreaterthan0x02).IEEEStd802.3ah-2004Section,Page215,LoopbackControlOAMPDU.Value0x00forLoopbackControlOAMPDUcom-mandisreserved-shallnotbetransmitted,shouldbeignoredonreceptionbyOAMclient.(Note:TestforDUTshouldignoreLoopbackControlOAMPDUCommandwithValue0x00).IEEEStd802.3ah-2004Section,Page215,LoopbackControlOAMPDU.Value0x03-0xFFforLoopbackControlOAMPDUcommandisreserved-shallnotbetransmitted,shouldbeignoredonreceptionbyOAMclient.(Note:TestforDUTshouldignoreLoopbackControlOAMPDUCommandwithValue0x04).IEEEStd802.3ah-2004Section,Page215,LoopbackControlOAMPDU.AMT51nLinkEventTVs,values0x05-0xFDforypefieldisreserved-shallnotbetrasmitted,shouldbeignoredonreceptionbyOAMclien.(Note:DUTshouldntsendLinkEventTVwithtypefield0x05-0xFD).IEEE004Section57.5.3,Page219,LinkEvetTVs.52DetectionofaTVtype0x00sholdindicatetherearenomoreTVstoprocess(thelengthandvalueoftheype0x00TVcanbeignored).IEEE004Section57.5.1,Page215,Parsing.53Vswithlenths0x00or0x01sholdbeconsid-eredinvalid,andtheOAMPDUsholdbeconsi-eredtohavenomoreTVs.IEEE004Section57.5.1,Page215,Parsing.54Vswithunknownorunexpectedtypesshouldbeignred.IEEE004Section57.5.1,Page215,Parsing.IEEEStd802.3ah-2004Section57.5.1,Page215,Parsing.IEEEStd802.3ah-2004Section57.5.1,Page215,Parsing.IEEEStd802.3ah-2004Table57-7Section,Page217,LocalInformationTLV.NEGATIVEIEEEStd802.3ah-2004Sec-tion,Page216,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page216,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page216,LocalInformationTLV.IEEEStd802.3ah-2004Section57.5.2,Page216,InformationTLVs.IEEEStd802.3ah-2004Section57.5.2,Page216,InformationTLVs.IEEEStd802.3ah-2004Table57-8Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Table57-8Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page216,LocalInformationTLV.IEEEStd802.3ah-2004Section57.5.2,Page216,InformationTLVs.IEEEStd802.3ah-2004Section57.5.2,Page216,InformationTLVs.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page217,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page218,LocalInformationTLV.IEEEStd802.3ah-2004Section,Page218,LocalInformationTLV.OAMTso61nLocalInformationTVs,reservedbis(15:)shallbesettozerowhensendinganOAMPDU,andshouldbeignredonrecepionforcomatibilitywithfutureuseofreservedbis.(Note:stforDUTshouldignrereservedOAMPDUConfigurationBis).IEEESection,Page218,LcalInformaionT.62nclfrmtionVs,MaximumOAMPDUsizeis-bitfieldwhichrepresensthelrgestOAMPDU,inoctes,supportedbytheDTE.Thisvleiscmardoteremote'sMaximumPDUSizeandthesmallrofthetwoisused.IEEESection,Page218,LcalInformaionT.63heRemoteInformationTVshallbeacopyofthelastreceivedLocalInformationTVfomthereoeOAMpee,withtheexcepionoftheInformationypefield.(Noe:ithDUTasActiveAMDE).IEEESection,Page219,RemoteInformationT.64heRemoteInformationTVshallbeacopyofthelastreceivedLocalInformationTVfomthereoeOAMpee,withtheexcepionoftheInformationypefield.(Noe:WithDUTasPassiveOAMDTE).IEEESection,Page219,RemoteInformationT.65nLinkEventTVs,value0xFFforypefieldisreserved-shallntbetransmitte,sholdbeignredonreceptionbyOAMclien.(Note:DUTshouldnotsendanyLinkEvetTVwithtypefield0xFF).IEEE004Section57.5.3,Page219,LinkEvetTVs.66hiseventisgeneraedifthesymblerrorcountisequaltoorgreaterthanthespeiiedthresholdforhtpdIEEESection,Page220,ErroredSymbolPeriodEvet67ErroredSymbolPeriodEventusesalengthvalueof40(0x28).IEEESection.section(b),Page220,EventLength.68hiseventisgeneratediftheeroredframecountisequaltoorgreaterthanthespecifiedthresholdforthatpriod.IEEESection,Page221,ErroredFrameEventT.69ErroredFraeEventusesalenthvalueof26(0x1A).IEEESection,Page221,ErroredFrameEventT.610Thiseventisgeneratediftheeroredframecountisgreaterthanorequaltothespeiiedthresholdforthatpriod(forexample,iftheeroredfraecoutisgreaterthanorequalto10forthelast1,000,000raesrceiv).IEEESection,Page221,ErroredFramePeriodEvent61ErroredFraePeriodEventusesalengthvalueof28(0x1C).IEEESection,Page222,ErroredFramePeriodEvent612Thiseventisgeneraedifthenumberoferroredfraesecondsisequaltoorgreaterthanthespeci-fiedthresholdforthatperiod.IEEESection,Page222,ErroredFrameSecondsSum-ayntErroredFrameSecondsSummaryEventusesalengthvalueof18(0x12).IEEEStd802.3ah-2004Section,Page223,ErroredFrameSecondsSum-maryEventTLV.ribe71MIBvariablesarequeriedthroughtheuseofri-ableRequestOAMPDUsandreturnedthroughtheuseofariableRsponseOAMPDUs.IEEEdSection57.6,Page224,riables.72AnOAMclientmayrequestoneormorevariablesineachrialeRequestOAMPDU.IEEEdSection57.6,Page224,riables.73AnOAMclientmayrequestoneormorevariablesineachrialeRequestOAMDU.EachreturnedriableConainerresideswithinasingleariableResposeOAMPDU.IEEEdSection57.6,Page224,riables.74alue0x25-3FforcodingfieldisreservedforAttribueIndications-shallnotbetrasmitted,shouldbeignredonreceptionbyOAMclien.(Note:DUTsholdnotsendvariableindicationwithcode53IEEE004Section57.6.5,Page227,riableIndications.75DetectionofaariableBrachfieldequalto0x00shouldindicatethereaenomoreariableDscrip-torstoprocess(subsequentfieldscanbeignore).IEEE004Section57.6.3,Page226,Parsing.76DetectionofaariableBrachfieldequalto0x00shouldindicatetherearenomoreariableConain-erstoproess(subsequentfieldscanbeignred).IEEE004Section57.6.3,Page226,Parsing.77nrialeIndicatios,value0x00forcodingfieldisreserved-shallnotbetransmitte,shouldbeignoredonreceptionbyOAMclien.(Note:DUTshouldnotse