以太网OAM协议解析及测试关注点

1、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 OAI介 32以太网 OAMfc 网络上的应用 33OAMPDU 文解析及工作原理 43.1报文解析 43.2几种最常见的 OAMPDU 法：73.2.1InformationOAMPDU73.2.2EventNotificationOAMPDU73.2.3LoopbackControlOAMPDU83.3以太网 OAMT 作原理：83.3.1建立以太网 OAM1 接：83.3.2链路监控 103.3.3远端故障

2、检测 113.3.4远端环回 124Featurelist134.1主要功能 134.2工作原理 134.3EventNotification 的处理 144.4OAMPDU 文 164.5LocalInformationTLVs174.6RemoteInformationTLVs184.7LinkEventTLVs184.8VariablesDescriptorsandContainers195测试关注点：205.1概述：205.2具体测试点：211 以太网 OA 晌介以太网OAM（Operations,AdministrationandMaintenance,操作、管理和维护）是一种监控网

3、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。2 以太网 OAMfc 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SDHt目比，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。802.3ah的以太网OAMfc要是链路方面的监测和维护，是一种偏物理层的OAM它主要应用

4、在网络的边缘设备上（接入层），且OAMPD报文只能转发一跳，主要用来监测链路质量、收集链路告警等。 而802.1ag的以太网OA娓偏网络和应用的OAM主要用在汇聚层和核心层上， 它的OAMPDU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MPLSOA则部分参考了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OAMft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

5、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OAM3OAMPDU 文解析及工作原理4.3 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0 x8809。Common,fixedh已日forallOAMPDUs。Subtype:以太网

6、OAM报文的协议子类型，为0 x03。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。0 x00表示InformationOAMPDU、0 x01表示EventNotificationOAMPDU、0 x04表示LoopbackControlOAMPDUFlags域：主要用来标示链路的故障信息:Table57-3FlagsfieldBir(ONameDescription15:7ReseiTedbitshallbejettozeioLliensendinzanOAMPDU.nndshouldb*ignoredoureceptionfor

7、canapatibilirrwithfiitureuseofrtn-edbits6RemoteStableWhenremoterate_valtdissettoTRUE,theRemoteStableandRemoteEvaluatingvaluershUbeicopyoftheLastreceivedLocalStableandLocalEraluatiiigvaluesbcuitheremoteOAMpeer.Othervise,thRemoteStableandRemoteEaluafingbits511MlbetoQ.5RemoteEaluarinE4LocalStableLocalS

8、tableandLocalE.alustingformatwo-bitenccdiusbelow:4:3CixO=LocalDTEUnsatisfied.Diacovet-;cannotccmplele0 x1=LocalDTEDiscoveivptoces购占norcompleted0 x2=LocalDTEDiscoveryproceBascompkTed0 x3-Resened.Tbisvalweshallnotbesent.Ifthevalue0 x3isteceived.itshouldbeignoredaudnotchangetheJa$treceivedvalue3LocalEv

9、aluating2CnticalEeut1=Aciiticdleventhasoccurred.0=AciiticaleventLuaoccurred.1DyingGaspI=Anuniecc/eiablelocalfailureccnditicnhasotciuTed.0=Anumecoeiablelocalfailureconditioahasuotocculted0LiukFaultIliePHAha&detectednfrmlroccutiedinthereceiveduechonofthelocalDTE(e.f.link.Physicallaver).1=Localcl&a

10、mp;vacesreceivepathhas.derctedafault.0=Localdevicereceivepathhasnotdetectedafault.NOTE-Thedeflmti0nofthespecificfaultscomptisiiigtheCriticalEvent.DVIHMGaip.andLinkFaultflag;:jiuipkcienTationspecificnadbeyondrhescopeofrhisuudtd.值得注意白是对于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

11、。这可能要厂家根据需要自行定义。4.4 几种最常见的 OAMPDU 用法:InformationOAMPDUEventNotificalionOAMPDULcwpbackcontrolOAMPDU在ETHOAW最常见的三种OAMPDU文分另I是InformationOAMPDU、EventNotificationOAMPDU和LoopbackControlOAMPDU，下面将分别加以介绍：4InformationOAMPDU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：OctetsLocallnfom

12、)at)onTLVefdsOrtels6DestinationAddress*InformationType16SourceAddress事/InformationLength12Length/TypeOctets-InfomattonTLV侍)z/1OAMVersion11SubtypeJ11/16|LocalInformationTLVRom泊InformationTLVRevision22Flagsi卜T、State11Code=0 x00/161OAMConfiguration142-1496Data/Pad卜1hfomatfon4IlOAMPDUConfiguration24FCS、

13、n|LTLV#31JIOUI3VendorSpecificInfo44EventNotificationOAMPDUCodeLocalInfoTLVRemoteinfoTLVCodeseqLinkeventTLVCodeOAMRemoteLoopbackcommandDestaddr SourceaddrType SubtypeFlagsCodeData/PadCRC61442-1496（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：Octets66212142-14964DestinationAddressSource

14、AddressLength-TypeSubtype二网 8Code=0 x01Data/PadFCSOctets1=-I/2SequenceNumbe1r,sLinkEventTLVLinkEventTLVEventTypeOctets1EventLength1EventTimeStamp2Window8Threshold8Errors8ErrorRunningTotal8EventRunningTotal4LinkEvent)SnoredSymbolPeriodEvent3.2.3LoopbackControlOAMPDU（环路控制OAMPDU）报文主要用于远端环回控制。环回控制OAMPDU

15、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：Octets662I2I1414DestinationAddressSourceAddressLength/TypeSubtypeFlagsCode=0 x040cte忸Data1OAMRemoteLoopbackcommandPadFCS3.3 以太网 OAM 工作原理:建立以太网 OAM 连接：deriveactivepassiveIhfninationOAMPDUABInfoiikMTioriOAMPCU|establish以太网OAM连接过程也称作Discov

16、ery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InformationOAMPD晌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OA睡接，如果两端的以太网OAMLoopback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

17、过程可以不口以对以太网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LoopbackControlOAMPDUJ可以不口以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可以不口以发送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

18、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。3.3.2 链路监控ErrorOccmedleblish链路监控用于检测和发现链路层的故障。以太网OAM禾1J用EventNotificationOAMPDU勺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

19、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）3.3.3 远端故障检测UhidirectioikdllinkfailestablishOAMPDU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(D

20、yingGasp):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AWB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文通过另一条链路发送给Ao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。3.3.4 远端

21、环回01npthickCoiflIo|l(JAMPDUCAMPDUe$nbli3hLoopbackOAMPDU的底层转发流程:MediunrFigure57-4OAMremoteloopback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艮文以外的所有报文都将按照原路返回，而OAMPDU文将继续上送至被环回设备的CPUS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。4Featurelist4.1 主要功能ItemF

22、eaturSubclauseValue/CommentSupportOMOAMobjectclass30.3.6MustCSIOAMclientservice57.2.5MustISIInternalserviceinterfaces57.2.8Must*ACTVActivemode57.2.9Must*PASSPassivemode57.2.9Must*LBOAMremoteloopback57.2.11,TohloMustUNIUnidirectionaloperationiable57.2.12,TableRequiressupportforunidirectionalMust*EVNT

23、LinkEvents57.4.3.2,57.5.3Must*VARVariableRetrieval57.4.3.3,57.4.3.4May*OSPOrganizationSpecificOAMPDU57.4.3.6May*OSEOrganizationSpecificEvents57.5.3.5MayOSIOrganizationSpecificInformationTLV57.5.2.3May4.2 工作原理ItemFeatureSubclauseValue/CommentSupportOFS1Passivemodelimitedtransmission57.2.9.2Cannotsend

24、VariableRequestorMustOFS2Discoverystatediagram57.3.2.1ImplementedasdefinedinFigureMustOFS3Transmitstatediagram57.3.2.2ImplementedasdefinedinFigureMustOFS4OAMPDUtransmissionwhenlocal_pduissettoLFINFO57.3.2.2.6OnlyInformationOAMPDUswithLinkFaultbitofFlagsfieldandMustOFS5OAMPDUtransmissionwhenlocalpdui

25、ssetto57.3.2.2.6NoOAMPDUtransmissionallowedMustOFS6OAMPDUtransmissionwhenlocal_pduissetto1hl匚 c57.3.2.2.6OnlyInformationOAMPDUscanbeMustOFS7OFS8INIOOAMPDUtransmissionwhenlocal_pduissettoANY:OAM_CTL.requestserviceprimitivewithoneormore57.3.2.2.6Reqsm盛dransmissionofInformationOAMPDUwithappropriatebits

26、ofFlagsfieldsetMustOFS9criticallinkeventOAMPDUFlagsfieldreservedencodingsRemoteStableandRemoteEvaluatingbitsTable573RequeststransmissionofEncodingof0 x3isnottransmittedEncodingof0 x3isnottransmittedMustOFS11 ReservedbitsTable573ReservedbitsareMustOFS12 OAMPDUCodefield57.4.2.2zeroonOnlydefinedCodefie

27、ldvaluesarepermittedinMustOFS13 OAMPDUreceptionwhen57.3.2.3OnlyInformationMustOFS14local_pduisnotsettoANYOAMPDUreceptionwhenlocal_pduissettoANY57.3.2.3OAMPDUsaresenttoAllOAMPDUsaresenttoOAMcliententityMustOFS15 Multiplexerstatediagram57.3.3ImplementedasdefinedinFigureMustOFS16Multiplexertransparentp

28、ass-through57.3.3.2Providetransparentpass-throughofframesfromsuperiorsublayertosubordinatesublayerMustOFS17EffectofOAMPDUonaframealreadysubmitted57.3.3.2HasnoeffectMustOFS18 Parserstatediagram57.3.4ImplementedasdefinedinFigureMustEventNotification 的处理ItemFeatureSubclauseValue/CommentSupportEV1Respon

29、setoCriticalEvents57.2.10.3Set/clearFlagbitsbasedonOAM_CTL.requestMustEV2CriticalEventreception57.2.10.4IndicatedviaFlagsfieldofOAMPDU.indicationMustEV3LinkEventreception57.2.10.4IndicatedviaOAMPDU.indicationserviceprimitivewithallreceivedEventNotificationOAMPDUsMustOAMPDU 报文ItemFeaturSubclauseValue

30、/CommentSupportPDU1Tagging57.4.2OAMPDUscannotbetaggedMustPDU2OAMPDUstructure57.4.2AsdefinedinFigure57电andfielddefinitionsMustPDU3MinimumOAMPDUsize57.4.2SupportOAMPDUsminFrame-SizeinlengthMustPDU4InformationOAMPDUframestructure57.4.3.1ShowninFigure5710MustPDU5InformationOAMPDUwhenlocal_pdusettoLF_INF

31、O57.4.3.1DatafieldcontainszeroInformationTLVsMustPDU6InformationOAMPDUwhenlocal_pdunotsettoLF_INFOremote_state_valid=FALSE57.4.3.1DatafieldcontainsLocalInformationTLVDatafieldcontainsLocalandRemoteInformationTLVsMustPDU8Typevalues0 x03-0 xFDTable574NottobesentMustPDU9Typevalue0 xFFTable574Nottobesen

32、tMustPDU10EventNotificationOAMPDUframestructure57.4.3.2ShowninFigure5711MustPDU11EventNotificationOAMPDUSequenceNumber57.4.3.2ThefirsttwobytesoftheDatafieldcontainaSequenceNumberencodedMustPDU12EventNotificationOAMPDUEvent(s)57.4.3.2DatafieldcontainingoneormoreLinkEventTLVsMustPDU13VariableRequestOA

33、MPDUframestructure57.4.3.3ShowninFigure5712MayPDU14VariableRequestOAMPDUDatafield57.4.3.3DatafieldcontainsoneormoreMayPDU15VariableResponseOAMPDUframestructure57.4.3.4ShowninFigure5713MayPDU16VariableResponseOAMPDUDatafield57.4.3.4DatafieldcontainsoneormoreMayPDU17LoopbackControlOAMPDUframestructure

34、57.4.3.5ShowninFigure5714MustPDU18LoopbackControlOAMPDUDatafield57.4.3.5DatafieldcontainsasingleOAMRemoteMustPDU19Commandvalue0 x00Table575NottobesentMustPDU20Commandvalues0 x03-0 xFFTable575NottobesentMustPDU21OrganizationSpecificOAMPDUframestructure57.4.3.6ShowninFigure5715MayPDU22OrganizationSpec

35、ificOAMPDU57.4.3.6Contains24-bitOrganizationallyMayLocalInformationTLVsItemFeaturSubclauseValue/CommentSupportLIT1LocalInformationTLV57.5.2.1Containsthefollowingfields:InformationType,InformationLength,OAMVersion,Revision,State,OAMConfiguration,MustLIT2LocalInformationTLVOAMVersionfield57.5.2.1Conta

36、ins0 x01toclaimcompliancetoMustLIT3LocalInformationTLVRevi-sionField57.5.2.1StartsatzeroandincrementedeachtimeaMustLIT4LocalInformationTLVStatefield57.5.2.1AsdefinedinTable577MustLIT5LocalInformationTLVStatefieldParserAction0 x3value57.5.2.1IsnottransmittedMustLIT6ReservedbitsTable577Reservedbitsare

37、zeroontransmissionMustLIT7LocalInformationTLVOAMConfigurationfield57.5.2.1AsdefinedinTable57勺MustLIT8ReservedbitsTable578ReservedbitsarezeroontransmissionMustLIT9LocalInformationTLVOAMPDUConfiguration57.5.2.1AsdefinedinTable57MustLIT10LocalInformationTLVOUIfield57.5.2.1AsdefinedinTable5710MustLIT11R

38、eservedbitsTable57PReservedbitsarezeroontransmissionMustLIT12LocalInformationTLVVendorSpecificInformationfield57.5.2.1AsdefinedinTable5711MustRemoteInformationTLVsItemFeaturSubclauseValue/CommentSupportRIT1RemoteInformationTLV57.5.2.2ContainstheInformationTypefieldspecifyingtheRemoteInformationTLVTy

39、pevalueandallremainingfieldsarecopiedfromthelastreceivedLocalInformationTLVfromremoteOAMpeerMustLinkEventTLVsItemFeaturSubclauseValue/CommentSupportET1ErroredSymbolPeriodEventTLVstructure57.5.3.1Containsthefollowingfields:EventType,EventLength,EventTimeStamp,ErroredSymbolWindow,ErroredSymbolThreshol

40、d,ErroredSymbols,ErrorRunningTotal,EventPimninnTctalMustET2ErroredFrameEventTLVstructure57.5.3.2Containsthefollowingfields:EventType,EventLength,EventTimeStamp,ErroredFrameWindow,ErroredFrameThreshold,ErroredFrames,ErrorMustET3ErroredFramePeriodEventTLVstructure57.5.3.3RunningTotal,EventContainsthef

41、ollowingfields:EventType,EventLength,EventTimeStamp,ErroredFrameWindow,ErroredFrameThreshold,ErroredFrames,ErrorMustRunningTotal,EventET4ErroredFrameSecondsSummaryEventTLVstructure57.5.3.4Containsthefollowingfields:EventType,EventLength,EventTimeStamp,ErroredFrameSecondsSummaryWindow,ErroredFrameSec

42、ondsSummaryThreshold,ErroredFrameSecondsSummary,ErrorMustET5OrganizationSpecificEventTLVstructure57.5.3.5Containsthefollowingfields:EventType,EventLength,OrganizationallyUniqueIdentifier,OrganizationSpecificValueMustET6OrganizationSpecificEventOrganizationally57.5.3.5Contains24-bitOrganizationallyMu

43、stET7Typevalues0 x05-0 xFDTable5712NottobesentMustET8Typevalue0 xFFTable5712NottobesentMustVariablesDescriptorsandContainers（主要用于 mib 管理）ItemFeaturSubclauseValue/CommentSupportVAR1VariableDescriptorstructure57.6.1AsdefinedinTable5713MayVAR2VAR3VariableDescriptor/VariableBranchreferencesattributesdoe

44、snotreferenceactions57.6.157.6.1Ifanobjectorpackageisreferenced,onlyattributescanbefoundwithinVariableContainerActionsarenotfoundinVariableContainersMayVAR4VariableContainer57.6.2AsdefinedinTable5714MaystructurefoianattributeVAR5VAR6VariableContainer/VariableBranchreferencesattributes57.6.257.6.2Ifa

45、nobjectorpackageisreferenced,onlyattributescanbefoundwithinVariableContainerActionsarenotfoundinVariableContainersMaydoes notreferenceactionsVAR7Type value0 x00Table5716NottobesentMayVAR8Type values0 x02-0 x1FTable5716NottobesentMayVAR9Type values0 x25-0 x2FTable5716NottobesentMayVAR10Type values0 x

46、45-0 x5FTable5716NottobesentMayVAR11Type values0 x65-0 x7FTable5716NottobesentMay5 测试关注点：概述：由于ETHOA睡TN70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：（一）协议一致性测试：OAMP兆文一致性测试协议状态机测试（二）功能测试：故障监测链路监测远端环回（三）功能组合测试：与macl1的组合测试与lacp的组合测试与流控的组合测试（四）性能规格测试：多端口同时启用大流量情况测试（五）组网应用测试复杂流量测试长时

47、间老化测试（六）异常及攻击测试异常操作异常攻击具体测试点:NumberAssertionReferenceSetup/VerificationTests1.1OAMPDUstraverseasinglelink,beingpassedbetweenpeerOAMentities,andassuch,arenotforwardedbyMACclients(e.g.,bridgesorswitches).IEEEStd802.3ah-2004Section57.1.1,1.2Amechanismisprovidedtoindicatetoapeerthatthereceivepathofthelo

48、calDTEisnon-operational.IEEEStd802.3ah-2004Section57.1.2,SummaryofObjectivesandMajorConcepts.1.3OAMremoteloopbackisanintrusiveoperationthatpreventsalinkfrompassingframesbetweentheMACclientofthelocalDTEandtheMACclientoftheremoteDTE.IEEEStd802.3ah-2004Section57.1.5.5,FrameLossDuringOAMRemoteLoopback.1

49、.4TheOAMclientdoesnotrespondtoillegalrequestssuchasVariableRequestandLoopbackControlOAMPDUsfromPassiveDTEs.(Note:DUTasactiveshouldnotrespondtoVariableRequestOAMPDUsfrompassiveANVL).IEEEStd802.3ah-2004Section57.2.4,Page188,ResponsibilitiesofOAMClient.1.5TheOAMclientdoesnotrespondtoillegalrequestssuch

50、asVariableRequestandLoopbackControlOAMPDUsfromPassiveDTEs.(Note:DUTasactiveshouldnotrespondtoLoopbackControlIEEEStd802.3ah-2004Section57.2.4,Page188,ResponsibilitiesofOAMClient.1.6DTEsconfiguredinActivemodeinitiatetheexchangeofInformationOAMPDUs.IEEEStd802.3ah-2004Section57.2.9.1,Page195,ActiveMode.

51、1.7DTEsconfiguredinPassivemodedonotinitiatetheDiscoveryprocess.IEEEStd802.3ah-2004Section57.2.9.2,Page195,PassiveMode.1.8PassiveDTEsshallnotsendVariableRequestorLoopbackControlOAMPDUs.(Note:DUTaspassiveshouldnotsendLoopbackControlOAMPDUstoactiveANVL).IEEEStd802.3ah-2004Section57.2.9.2,Page195,Passiv

52、eMode.1.9PassiveDTEsshallnotsendVariableRequestorLoopbackControlOAMPDUs.(Note:DUTaspassiveshouldnotsendVariableRequestOAMPDUstoactiveANVL).IEEEStd802.3ah-2004Section57.2.9.2,Page195,PassiveMode.FunctionalSpecifications2.1StatisticsfromboththelocalandremoteDTEcanbequeriedandcomparedatanytimewhiletheI

53、EEEStd802.3ah-2004Section57.2.11,Page196,OAMRemoteLoopback.2.2remoteDTEisinOAMremoteloopbackmode.Thesequeriescantakeplacebefore,duringorafterloopbackframeshavebeensenttotheremoteIEEEStd802.3ah-2004Section57.2.11,Page196,OAMRemoteLoopback.DTE.2.3AfterreceivingtheLoopbackControlOAMPDU,theremoteOAMclie

54、ntfirstsetsitslocal_par_actionparametertoLBanditslocal_mux_actionparametertoDISCARDviatheOAM_CTL.requestserviceprimitive,andthensendsanInformationOAMPDUwithupdatedstateinformationreflectingitslocal_par_actionsettoLBanditslocal_mux_actionparametersettoDISCARD.IEEEStd802.3ah-2004Section57.2.11.1,Page1

55、96,InitiatingOAMRemoteLoopback.2.4IfanOAMclienthassentaLoopbackControlOAMPDUandiswaitingforthepeerDTEtorespondwithanInformationOAMPDUthatindicatesitisinOAMremoteloopbackmode,andthatOAMclientreceivesanOAMremoteloopbackcommandfromthepeerdevice,thefollowingproceduresarerecommended:a)IfthelocalDTEhasahi

56、ghersource_addressthanthepeer,itshouldenterOAMremoteloopbackmodeatthecommandofitspeer.IEEEStd802.3ah-2004Section57.2.11.1,Page196,InitiatingOAMRemoteLoopback.2.5IfanOAMclienthassentaLoopbackControlOAMPDUandiswaitingforthepeerDTEtorespondwithanInformationOAMPDUthatindicatesitisinOAMremoteloopbackmode

57、,andthatOAMclientreceivesanOAMremoteloopbackcom-mandfromthepeerdevice,thefollowingproce-duresarerecommended:b)IfthelocalDTEhasalowersource_addressthanthepeer,itshouldignoretheOAMremoteloopbackcommandfromitspeerandcontinueasifitwereneverIEEEStd802.3ah-2004Section57.2.11.1,Page196,InitiatingOAMRemoteL

58、oopback.2.6received.WithintheremoteOAMsublayerentity,everynon-OAMPDU,includingotherSlowProtocolframes,isloopedbackwithoutalteringanyfieldoftheframe.IEEEStd802.3ah-2004Section57.2.11.2,Page196,DuringOAMRemoteLoopback.2.7AfterreceivingaLoopbackControlOAMPDUwiththeDisableOAMRemoteLoopbackcommand,therem

59、oteOAMclientfirstsetsthelocal_par_actionandlocal_mux_actionparameterstoFWDviatheOAM_CTLrequestserviceprimitiveandthensendsanInformationOAMPDUwithupdatedstateinformationreflectingthelocal_par_actionandlocal_mux_actionparameterssettoFWD.IEEEStd802.3ah-2004Section57.2.11.3,Page196,ExitingOAMRemoteLoopb

60、ack.2.8Toensurecorrectoperation,theOAMclientneedsto,withinonesecondofreceivingaLoopbackCon-trolOAMPDUwiththeEnableOAMRemoteLoop-backcommand:a)Setitslocal_par_actionparametertoLBandthelocal_mux_actiontoDISCARDviatheOAM_CTLrequestserviceprimi-tive.b)SendanInformationOAMPDU.IEEEStd802.3ah-2004Section57.2.11.6,