8032v2和v1v3对照学习笔记v2篇教学内容.docx
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8032v2和v1v3对照学习笔记v2篇教学内容.docx
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8032v2和v1v3对照学习笔记v2篇教学内容
8032v2和v1,v3对照学习笔记_v2篇
G.8032/Y.13442010/03
Summary
APS
protectionswitchingmechanisms(characteristics,architectures)
ETHlayerEthernetringtopologies
incorporatesAmendment1(2010),
AppendixX(minimizingsegmentationininterconnectedrings)
multiplefaultsthatcouldcausesegmentationinanetworkofinterconnectedrings.
usesadditionalmanagementinformationandconfigurationofMEP
AppendixXI(end-to-endserviceresilience)
ringprotectiontointeractwiththefullserviceprotection
ITU-TG.8031/Y.1342
1Scope
APS
ProtectionswitchingmechanismsforETHlayerEthernetRingtopologies
TheETHlayerringmapstothephysicallayerringstructure.
2References
[ITU-TG.805]
[ITU-TG.806]2009版
[ITU-TG.808.1]
[ITU-TG.809]
[ITU-TG.870]
[ITU-TG.8010]
[ITU-TG.8021]
[ITU-TY.1731]
[IEEE802.1Q]
3Definitions
3.1Termsdefinedelsewhere
和1相比,唯一的区别是G.8021中多定义了一个ETHDi/ETHadaptationfunction(ETHDi/ETH_A)
3.2TermsdefinedinthisRecommendation
3.2.1Ethernetring
由ringnode形成的一个物理上闭合的回路,每个ringnode和邻接的ringnode相连。
注意表述中说的是ethernetring和ethernetringnode,并非erpring或erpringnode,即讨论物理层,Ethernet层面,环的组成和连接,erpring和node映射到该ring物理结构上,实际情况中,如果其中有非支持erp的ringnode,应视为透明的link;由此产生的单通状态【如cc单通,或一侧link单通】按erp单通逻辑处理。
3.2.2Ethernetringnode
Anetworkelementwhichimplementsatleastthefollowingfunctionalities:
ETH_C+ETH_FFforforwardingAPS
Tworingports,includingETHDi/ETHadaptationfunction
ERPcontrolprocesscontrollingtheblockingandunblockingoftrafficovertheringports.
上述几个function在G.8021中定义,需要进一步学习
3.2.3ERPinstance
3.2.4interconnectionnode
表述相当拗口,逻辑还是简单的,简单说互联节点,就是连接多个ring的节点;多个ring中,一个是majorring,每个互联节点有2个ringport参与,其它都是sub-ring,每个互联节点有且只有一个ringport参与.
Becommonto与…共有
互联节点和共享节点不同,共享节点是多个ring共享该节点,各个ring彼此独立,每个ring,有2个ringport参与
在没有定义majorring和subring的时候抛出interconnectionnode的概念,又没有图说明,是不妥当滴。
3.2.5majorring
物理和逻辑上都闭合的环,共享link属于majorring,每个共享节点有2个ringport参与
3.2.6R-APSvirtualchannel
叙述相当稀烂;ERPS中有2种通道,trafficchannel和R-APSchannel,在多环的情况下,子环物理和逻辑上未闭合,v1a1中引入virtualchannel的概念,让subring的R-APSmessage在主环中透传,从而实现子环逻辑上的闭合
3.2.7ringMEL
3.2.8ringprotectionlink(RPL)
3.2.9RPLneighbournode:
逻辑很容易理解,但引入neighbour不过是能blockrpl的另一端,有什么现实意义?
减少无效流量侵占带宽?
3.2.10RPLownernode
Owner如何相应FS/MS请求?
3.2.11sub-ring
3.2.12sub-ringlink
Span这里如何翻译?
node之间的间距?
3.2.13waittoblocktimer
4Abbreviations
新增BPR,FS,MS,ID,TCM,VPLS
5Conventions
5.1Representationofoctets
多个8位元组表达一个2进制数,低位在前,高位在后
BINHEX
00000010011011006C02
8位元组内部,高位在前,低位在后
6Introduction
Mechanisms,APSapplyonETHring
wide-areamultipointconnectivity,moreeconomically(reducednumberoflinks)
highlyreliableandstableprotection,neverformloops
ringprotectionswitchingarchitecture
loopavoidance
atanytime,trafficmayflowonallbutoneoftheringlinks.
Ethernetflowforwardingfunction(ETH_FF)
thisRecommendationshallbeapplicableforamulti-ring/laddernetwork,ifthefollowing
principlesareadheredto:
a)R-APSchannelsarenotsharedacrossEthernetringinterconnections;[独立RAPS通道]
b)Oneachringport,eachtrafficchannelandeachR-APSchannelarecontrolled(e.g.,forblockingorflushing)bytheEthernetringprotectioncontrolprocess(ERPcontrolprocess)ofonlyoneEthernetring;[各环有独立控制的ringport,tc,rc,不共享]
c)Eachmajorringorsub-ringmusthaveitsownRPL.[独立RPL]
7Ringprotectioncharacteristics
7.1Monitoringmethodsandconditions
Switchingtriggercondition:
Condition就是SF,SForOK,其它方式没有定义
SFtriggerswitching
SFdefinedin8021,SFornofailed,notdefinedothercondition,i.e.SD
SFdefinedontransportentityofeachringlink
SF检测有threemonitoringmethods
Inherent---physicallayertrail
Sub-layer---tandemconnectionmonitoring(TCM).
Testtrail---extratesttrail(CCM?
)
对于ERP进程而言,不知道采用的何种defectsmonitoring方式,只知道传输实体(ringlink)SF或OK
7.2Ethernettrafficandbandwidthconsideration
无论ERP出于何种状态,都应该能提供足够的带宽保证业务和RAPS
CareshouldbetakenthatringlinkcapacitycancontinuetosupportallringAPS(R-APS)andservicetrafficthatisprotectedafterprotectionswitching
7.3Ethernetringprotectionswitchingperformance
Singlering(switchcompletiontime=transfertime)<50ms
withoutcongestion
allnodesinidlestatus
<1200kmfibrecircumference,
<16node
singlelinkfailure
所有其它情况不保证倒换时间小于50ms
特别提到子环虚通道场景,性能部分受主环性能影响,如果节点数,距离超过上述标准,则达不到50ms
8Ringprotectionconditionsandcommands
Conditions,这里conditions如何翻译?
条件,状态或其它?
似乎状态比较合理,ring可以出于2种状态,故障和无故障状态,从宏观上说环的状态用idle和protection表述更合适,并且ring也不止idle和protection状态,不知道这里用2种消息来表述环的状态是什么意思,当然另一种理解是,当环上检测到SF,则SF消息在环上传播遍历所有节点,恢复时NR消息传遍所有节点,这是从微观角度看环的状态
Signalfail(SF)
Norequest(NR)
Commands
Forcedswitch(FS)[FS或MS可以同时配多处吗?
假如可以同时多处配FS或MS,那么环上同时多个堵点,从实际工作上说同时配多处没有意义,但又可能不做检查允许这样做]
Manualswitch(MS)
Clear
a)Clearinganactivelocaladministrativecommand(e.g.,forcedswitchormanualswitch).[clear优先级高,假定可以同时多配FS/MS,仍然清除所有FS/MS的配置]
b)TriggeringreversionbeforetheWTRorWTBtimerexpiresincaseofrevertiveoperation.[在WTR或WTR超时前触发恢复]
c)Triggeringreversionincaseofnon-revertiveoperation.
下面3种命令没有实现
Lockoutofprotection–Thiscommanddisablestheprotectiongroup.
ReplacetheRPL–ThiscommandmovestheRPLbyblockingadifferentringlinkandunblockingtheRPLpermanently.
Exercisesignal–ExerciseoftheR-APSprotocol.Thesignalischosensoasnottomodifythepositionoftheblockedringport.
9Ringprotectionarchitectures
9.1Revertiveandnon-revertiveswitching
Switchconditionscleared(SFisremoved,ms/fsiscleared)
Revertive(WTR->switchovertoworkingtransportentity)
Advantage:
workingtransportentitymaybeoptimized
Disadvantage:
theexpenseofanadditionaltrafficinterruption
Non-revertive(noswitch)
Advantage:
nottheexpenseofanadditionaltrafficinterruption
Disadvantage:
mayusethenon-optimizedtransportentity
9.2Protectionswitchingtriggers
3个倒换触发来源,SF,RAPS,operatorcontrol。
ERP控制进程消息输入包括本地消息和外部消息,各种消息优先级不同,任意时候,只响应最高优先级的消息
a.SF,ithasahigherpriority
b.thereceivedR-APSmessagerequeststoswitchandithasahigherprioritythananyotherlocalrequest(i.e.假定故障恢复,wtr超时,某个故障邻接node将收到owner的NRRB消息,此时如果NRRB消息优先级最高,就会触发倒换)
c.initiatedbyoperatorcontrol(e.g.,forcedswitch,manualswitch)ifithasahigherprioritythananyotherlocalrequestorfar-endrequest
9.2.1Signalfaildeclarationconditions
SFisdefinedin8021
9.3ProtectionswitchingmodelsonasingleEthernetring
举了一个4nodes单环的例子,每个环节点抽象为应用了若干function
ETHcharacteristicinformation(ETH_CI)即以太的报文
ETH_FF某个特定的vlan
Ethernetflowpoint(ETH_FP)某个端口
对图中的圆圈可以理解为某个ETH_FF,若干端口加入其中,上面承载的是ETH_CI的业务,ERPProcess控制ETH_FF实现对ring端口block或unblock,flushdb等
图1正常情况
图2SF
图3引入CCM,MEP
图4解释CCM如何工作
IfaMEPdetectsadefect,whichcontributestoanSFdefectcondition,itinformstheERPcontrolprocessthatafailureconditionhasbeendetected.
AnERPcontrolfunctionusestheETH_CI_SSFinformation,forwardedfromtheETHx/ETH-m_A_Sk,toasserttheSFconditionoftheringlink.
R-APSprotocol用R-APSmessage交换消息
ETHDi/ETH_A功能模块负责解析和生成R-APSmessage
ToERPprocess:
R-APStoETH_CI_RAPS,
Toringport:
ETH_CI_RAPStoR-APS
注意:
ERPprocess收到的为ETH_CI_RAPS除了送ERP处理,还会通过RAPS-FF向下游转发
AreceivedR-APSmessageisalsoforwardedtotheETH_FF
9.4Trafficchannelblocking
BlockingtrafficissupportedbyexcludingtheconnectionpointfromtheETH_FFfunctionsfortheoneormoreVLANIDsofthetrafficchannelcontrolledbytheERPInstance
EachERPinstanceshallonlyblockorunblocktheVLANIDsofthetrafficchannelsofthesetofVLANsassignedforprotectionbythatERPinstance.
9.5R-APSchannelblocking
R-APSchannelVLANtrafficforwardingisalwaysblockedatthesameringportswherethetrafficchannelisblocked,exceptonsub-ringswithoutR-APSvirtualchannel
除了子环w/ovc情况下,trafficchannel和rapschannelblock不同以外,其它情况blocking或unblocking都保持一致,并且二者blocking的逻辑相同
但blocking时一些细节不同
对于trafficchannel,承载的是业务数据,若在某个block的端口【ingress:
线路到端口】收到,由于该端口已经从vlan中excluded,所以不会转发,同理试图通过该节点转发的数据【egress:
switch到port】也会被block,不存在进一步处理的可能
对于R-APS,不转发收到的R-APS,但收到的R-APS送ERP处理
即使端口block,但ERP仍可通过block的端口发送自己产生的R-APS
Onsub-ringswithoutR-APSvirtualchannel,theR-APSchannelisneverblockedonanyofitssub-ringnodes.However,inthiscase,theR-APSchannelisterminatedattheinterconnectionnodes.
9.6FDBflush
removingMACaddresses
flushonlytheFDBfortheVLANIDs
9.7Ethernetringprotectionswitchingmodelsforinterconnection
6点双环,很简单
9.7.1RinginterconnectionmodelwithanR-APSvirtualchannel
图9.7是一个subringport,一头连子环,另一侧的network是主环,基本逻辑和单环是一样的,区别在于多了一个topologynotice,即tc,子环发生倒换,通知主环动作;另外子环的RAPS会穿过主环
疑问:
为什么要vc?
interconnectionnode提供了子环到其它网络的连接
AnR-APSvirtualchannelprovidesR-APSconnectivitybetweenthisinterconnectionnodeandtheotherinterconnectionnodeofthesamesub-ring,overthenetwork
CaremustbetakentoensurethatthelocalR-APSmessagesofthesub-ringbeingtransportedovertheR-APSvirtualchannelintotheinterconnectednetworkcanbeuniquelydisambiguatedfromthoseofotherinterconnectedringR-APSmessages.
Thiscanbeachievedby,forexample,usingseparateVIDsfortheR-APSvirtualchannelsof
differentsub-rings.
R-APS在主环通过不同的VID传输
主环R-APS->ETHDi/ETH_A------>ETHDi/ETH_A-----→ERP1
子环R-APS--→ETHDi/ETH_A------>R-APS_2_FF----→ETHDi/ETH_A-----→ERP2
Topology_Changesignal
当子环发生倒换(捕捉条件:
flushDB),子环发送该信号给主环,主环可以选择做相应动作
从图9.8上看,多环的ERPprocess之间只有子环tc的一个单向通讯通道,而子环的RAPS在主环上只是一个普通的vlan
areseparatedinERP1usingdifferentR-APSVIDs应该是areseparatedinERPxusingdifferentR-APSVIDs
9.7.2RinginterconnectionmodelwithoutR-APSvirtualchannel(P.25)
无虚通道的模型,R-APS在
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