ZXR10-II級(jí)技能認(rèn)證備考試題庫(kù)大全-4簡(jiǎn)答題匯總

PAGEPAGE1ZXR10-II級(jí)技能認(rèn)證備考試題庫(kù)大全-4簡(jiǎn)答題匯總簡(jiǎn)答題1.WhatisthedifferenceofnetworkmandsinBGPandOSPF?答案：InBGP,networkmandenablesBGPtoannouncenetwork.InsteadofinitiatingBGPprocessoninterface,itonlypointsoutthenetworkBGPshouldannounce;whileinOSPF,networkmandnotonlycanannouceroute,butalsocaninitiateOSPFroutingprotocoloninterface.2.WhenexecutingmandshowipbgproutetoviewBGProute,ifthenexthopis,howdoesthisroutegenerate?Pleasegivetheprobablecases.答案：1.GeneratedviaredistributingIGProuteslocally;

2.Routeaggregationisadoptedbythisroutertogenerateaaggregatedroute.3.Whenlinkisdown,thetopologywillchange,thenewconfigurationmessagewillarrivetowholenetworkafteraperiodoftime,inwhatcondition,thenetworkwillformtermporaryloop?答案：Intheoldertopology,portsintheforwardingstateshouldbeblockedinthenewtopology,butitselfcannotfindthechangeoftopology,itwillcausethetermporaryloop.4.你負(fù)責(zé)一個(gè)中小型的辦公網(wǎng)的規(guī)劃和組建，該公司的辦公地點(diǎn)分布在某一辦公大樓的17~18層，每層人數(shù)在50~80人，公司已經(jīng)租用了某運(yùn)營(yíng)商的2M的E1線路（但是沒(méi)有申請(qǐng)多余的IP地址，只有一個(gè)接入地址）只有公司高層領(lǐng)導(dǎo)（10人以下）允許通過(guò)該線路上INTERNET。用戶要求整網(wǎng)采用自動(dòng)分配IP地址的方式接入用戶，根據(jù)公司的的不同部門劃分VLAN，有些部門是跨樓層分布的，需要控制各個(gè)部門相互訪問(wèn)的數(shù)據(jù)流，根據(jù)前期的了解，你發(fā)現(xiàn)部門內(nèi)部互訪流量較大，部門間互訪的流量較小，比例符合傳統(tǒng)的8:2原則。請(qǐng)你為該公司選擇合適的中興數(shù)據(jù)設(shè)備，并給出你的方案和理由。假設(shè)可供選擇的設(shè)備即可能的價(jià)格如下（在完成相同的功能時(shí)，注意控制成本）：

T64E（50萬(wàn)左右）,ZSR3884（1萬(wàn)~4萬(wàn)），T64G（20萬(wàn)左右）,ZXR103952（7千左右）,ZXR103928（5千左右）,ZXR102826S（1.5千左右）,ZXR102852S（2.5千左右）答案：選擇T64E以及T64G的不給分。選擇ZSR3884一臺(tái)＋2852S四臺(tái)或者ZSR3884一臺(tái)＋3952四臺(tái)均為較好的選擇。

理由需要考慮到設(shè)備對(duì)DHCPSERVER功能的支持，NAT功能的支持，E1接口的支持，設(shè)備端口數(shù)的選擇，成本的控制等。

回答合理均可給分。5.Iftwohostscanmunicatewitheachotherintwocases.

Notice：twoportsofSwitch1areinVLAN2,twoportsofSwitch2areinVLAN3

Case1：Pleaseseethefollowingfigure.

Case2：Pleaseseethefollowingfigure.

『圖片』答案：Case1：No。ThepacketsentfromPC-Awillbeaddedtag2viaTrunk-link,switch-2cannottransferittoPC-BbecausetheportthatPC-Bconnectstoisnotinthesamevlan.

Case2：Yes。ThepacketsentfromPC-Awillnotbeaddedtagviaaccess-linkbetweent9

ZXR10(config)#interfacefei_1/4

ZXR10(config-if)#ipaddress52

ZXR10(config)#interfacefei_1/2.30

ZXR6.ConfigureoneVPLSVPNbetweentwoPEs.AssumethatthebasicconfigurationofMPLSlabel-switchedpathhasbeenpleted.PleasegivethebasicVPLSconfigurationsontwoPEs.ThenameofVPNisTEST;

LOOPBACK1addressofPE1is;

LOOPBACK1addressofPE2is;

AccessportofPE1isfei_1/1,anduserVLANis50;

AccessportofPE2isfei_2/1,anduserVLANis80;答案：PE1：

VfiTEST

Vcid100

Pwtypeethernet-vlan

Peer

Interfacefei_1/1.50

Encapsulationdot1Q50

XconnectvfiTEST

Mplsldptarget-session

================

PE2：

VfiTEST

Vcid100

Pwtypeethernet-vlan

Peer

Interfacefei_2/1.80

Encapsulationdot1Q80

XconnectvfiTEST

Mplsldptarget-session7.OSPF重分發(fā)外部路由時(shí)，ext-1和ext-2的區(qū)別是什么？答案："第一類（ext-1）是指引入的是IGP路由（例如RIP，STATIC），由于這類路由的可信程度高一些，所以計(jì)算出的外部路由的花費(fèi)與自治系統(tǒng)內(nèi)部的路由花費(fèi)的數(shù)量級(jí)是相同的，即到第一類外部路由的花費(fèi)值=本路由器到相應(yīng)的ASBR的花費(fèi)值+ASBR到該路由目的地址的花費(fèi)值。

對(duì)于第二類（ext-2）外部路由是指引入的是BGP路由，由于這類路由的可信度比較低，所以O(shè)SPF協(xié)議認(rèn)為從ASBR到自治系統(tǒng)之外的花費(fèi)遠(yuǎn)遠(yuǎn)大于在自治系統(tǒng)之內(nèi)到達(dá)ASBR的花費(fèi)。所以計(jì)算路由花費(fèi)時(shí)將主要考慮前者，即到第二類外部路由的花費(fèi)值=ASBR到該路由目的地址的花費(fèi)值。如果該值相等，再考慮本路由器到相應(yīng)的ASBR的花費(fèi)值。"8.在哪些情況下，IGP-TE會(huì)洪泛鏈路信息？答案：IGP在如下情況下會(huì)洪泛TE信息。

■Linkstatuschange

■Configurationchange

■Periodicflooding

■Changesinthereservedbandwidth

■Afteratunnelsetupfailure9.BrieflydescribePPPpartsandtheirfunctions.答案：1、LCP(LinkControlProtocol)takeschargeofestablishing,maintenantingandterminatingaphysical-link

2、NCP（NetworkControlProtocol）isafamilyprotocol,takechargeofseeingwhatnetworkprotocolisrunonphysical-linkandsolvingtheproblemshappenedonsupernetworkprotocol

3、authenticationprotocolcontainsPAP（PasswordAuthentication

Protocol）CHAP（Challenge-HandshakeAuthenticationProtocol）10.Pleaselist4pointsontheprotocolthatmayusedforprotocolfailuredetectionwhenL3MPLSVPNbrokendown(nosequencerequirement)答案：對(duì).checkifMP-BGPneighborcanbeinitiatedorcreatednormally;2.Checkifinnerlabelcanworknormally;3.Checkifoutlabelcanworknormally;4.Checkifroutecanimplementnormallearningfunction;5.Checkiflabelforwardingtableworksnormally,etc.11.BGP消息有哪幾種類型,請(qǐng)闡述各自的作用.答案：

BGP共有4種類型的消息,分別是OPEN，UPDATE，NOTIFICATION和KEEPALIVE，分別用于建立BGP連接，更新路由信息，差錯(cuò)控制和檢測(cè)可到達(dá)性。12.MSTP中，交換機(jī)如何判斷鄰居和自己是否位于同一區(qū)域?答案：交換機(jī)會(huì)發(fā)送一份VLAN—實(shí)例映射表摘要，以及版本號(hào)和名稱，當(dāng)交換機(jī)接收到BPDU后，會(huì)提取摘要，并將其與自身的計(jì)算結(jié)果進(jìn)行比較，如果兩臺(tái)交換機(jī)在BPDU中所接收的參數(shù)不一致，負(fù)責(zé)接收BPDU的端口就會(huì)被宣布為邊界端口。13.在MPLSVPN網(wǎng)絡(luò)中，現(xiàn)有兩個(gè)VPN，VPNA與VPNB，VPNA中的主機(jī)1需要與VPNB中的主機(jī)2通訊，其他的用戶不可以跨VPN互通，請(qǐng)給出你的解決方案。答案：可通過(guò)VRF的EXPORTMAP以及IMPORTMAP來(lái)配置策略，匹配需要通訊的主機(jī)地址，然后將這兩條主機(jī)路由設(shè)置特定的RT值，在兩個(gè)VPN中互導(dǎo)。由于VPN的其他路由條目使用不同的RT，這個(gè)RT在兩個(gè)VPN中不進(jìn)行互相導(dǎo)入，這樣就可以做到其他用戶的隔離。14.請(qǐng)簡(jiǎn)述BGP建立鄰居的過(guò)程。答案：

（1）在要建立BGP會(huì)話的路由器之間建立TCP會(huì)話連接；（2）通過(guò)交換OPEN信息來(lái)確定連接參數(shù)（3）建立對(duì)等體連接關(guān)系后，最開(kāi)始的路由信息交換將包括所有的BGP路由，也就是交換BGP表中所有的條目（4）初始化交換完成以后，只有當(dāng)路由條目發(fā)生改變或者失效的時(shí)候，才會(huì)發(fā)出增量的觸發(fā)性的路由更新。15.簡(jiǎn)述RSVP-TEHotstandby的概念和工作原理？答案：RSVP-TEHotstandby功能是一種端到端的保護(hù)技術(shù)，采用一條隧道建立時(shí)直接建立2條路徑不同的LSP（另外一種方法是采用2個(gè)隧道來(lái)進(jìn)行端到端的保護(hù)），2個(gè)LSP擁有各自獨(dú)立的標(biāo)簽轉(zhuǎn)發(fā)條目，在頭節(jié)點(diǎn)一般表現(xiàn)有不同的出接口，下一跳地址；出標(biāo)簽可能相同，也可能不相同。通常會(huì)指定其中一個(gè)LSP為主LSP（Primarylsp），另一個(gè)為備份LSP（Secondlsp

實(shí)際上在轉(zhuǎn)發(fā)層面會(huì)同時(shí)寫(xiě)有兩個(gè)LSP的轉(zhuǎn)發(fā)條目并綁定，在正常情況下，使用主LSP的轉(zhuǎn)發(fā)條目用于轉(zhuǎn)發(fā)，一旦主LSP的出接口故障、主LSP的BFD檢測(cè)到故障、或者主LSP的協(xié)議層面檢測(cè)到故障，就會(huì)通知轉(zhuǎn)發(fā)層面將轉(zhuǎn)發(fā)切換到備份LSP的轉(zhuǎn)發(fā)條目上，以實(shí)現(xiàn)熱備份的快速切換。

在切換后，RSVP-TE協(xié)議會(huì)試圖重建主LSP，如果主LSP建立成功，重新寫(xiě)入主LSP的轉(zhuǎn)發(fā)條目后，又可以使得轉(zhuǎn)發(fā)層面將將轉(zhuǎn)發(fā)切換到主LSP的轉(zhuǎn)發(fā)條目上，恢復(fù)轉(zhuǎn)發(fā)。16.PleasebrieflystatethedifferencesbetweenInServmodelandDiffServmodelinQos.答案：InServmodel:ServiceappliesforspecificQoSserviceviasignaling.Thenetworkpreservesresourcestomatchthedemand.DiffServmodel:whennetworkcongestionoccurs,servicesareclassifiedintodifferentservcielevelstoavoidnetworkcongestionbycarryingoutdifferentiatedtrafficcontrolandforwarding.17.路徑回環(huán)是怎么樣產(chǎn)生的？Howispathloopbackcaused答案：如果網(wǎng)橋收到的是廣播幀，也要把該幀從除接收端口以外的所有其他端口轉(zhuǎn)發(fā)出去。但問(wèn)題是“透明”網(wǎng)橋畢竟不是路由器，它不會(huì)對(duì)報(bào)文做任何修改的，報(bào)文中不會(huì)記錄到底經(jīng)過(guò)了幾個(gè)交換機(jī)，如果網(wǎng)絡(luò)中存在環(huán)路，報(bào)文有可能在環(huán)路中不斷循環(huán)和增生，造成網(wǎng)絡(luò)的塞，因而導(dǎo)致了網(wǎng)絡(luò)中“路徑回環(huán)”問(wèn)題的產(chǎn)生。18.PleasebrieflydescribethedifferencebetweenOSPFandIS-ISfromtheareadivisionpointofview.答案：OSPFareadivisionisinterface-based,andeachinterfacebelongstoaspecificarea,theboundaryofareaisinsidetheboundaryrouter;IS-ISisdividedatrouter'slevelthatmeansonerouterbelongstoonearea,andtheboundaryisbetweentwobackbonerouters.19.請(qǐng)描述UAS中靜態(tài)綁定和動(dòng)態(tài)綁定的區(qū)別。答案：靜態(tài)綁定綁定接口interface實(shí)現(xiàn)固定ip地址的綁定，如專線用戶

動(dòng)態(tài)綁定綁定封裝類型，實(shí)現(xiàn)ip地址的動(dòng)態(tài)分配如pppoe撥號(hào)用戶。20.在跨域的BGPMPLSVPN配置中，如果采用OPTIONA的方式，即VRF-VRF直連的方式時(shí)，在兩個(gè)跨域的PE上，同一VPN的RT策略是否需要匹配，為什么？如果是采用OPTIONB的方式（通過(guò)EBGP的方式）情況又如何？答案：在OPTIONA的情況下兩PE上同一VPN的RT策略可以不匹配。在OPTIONB的方式下，配置的RT策略必須匹配。

因?yàn)椋涸贠PTIONA的方式下出了一個(gè)AS的時(shí)候RT屬性就已經(jīng)沒(méi)有了，兩臺(tái)跨域的PE設(shè)備只需要把對(duì)端看作自己的CE進(jìn)行配置即可，不需要RT的匹配。

而在OPTIONB的方式下：跨域的兩PE需要保存所有VPNv4路由信息，以通告給對(duì)端ASBR-PE。這種情況下，兩邊的VRF的RT策略需要匹配，否則不能正確導(dǎo)入到VRF路由表中。21.TheMANofacarrierhasthreeClassBaddresssegments,wherethereareseveraladdressesavailable.CarrierplanstoenableBGPforconnectionwithprovincenetwork,andthethreeClassBaddresssegmentswillbeadvertisedtoprovincenetworkafteraggregationtoavoidinfluencetoprovincenetworkduetorouteflappingwithinMAN.Torealizethisaim,whatshallwenoteinconfiguration?答案：It’snecessarytoconfigureBlackHoleRouting(BHR)onMANegressrouteronwhichBGPisenabledandpointthenexthopofthreeClassBaddressestoNULL0interfaceorLOOPBACKaddress(LOOPBACKaddressisremendedfordeviceofourpany)topreventhackerattackandtoavoidroutelooponuplinkofMANegressdevicewhentheaddresssegmentsarenotusedinMAN.22.DuringthedynamicVPDNuseraccessprocessauthenticatedviaRADIUS,usernameandpassworderrorappearsinuserdial-inprocess.Pleaseanalyzethereasonsforthiskindofproblem.答案：TunnelaccessattributesofVPDNuserunderRadiusauthenticationaredistributedbyradiusserver.BrasestablishesatunnelconnectiontopeerInsdeviceaccordingtoVPDNattributesinradiusattributes.Vpdnattributesinclude:IPaddressofIns,tunnelnameofInsandtunnelpasswordetc.Thereasonsforappearanceofusernameandpassworderrorinuserdial-inprocessare:

1）Theaccountinformationusedinuserdial-iniswrong(wrongusername,passwordordomainname).

2）Vpdnattributesdistributedbyradiusarewrong,whichleadstothefailureoftunnelconnectionestablishedbybras.

3）ItisabnormalforbrasdevicetoextractVPDNattributesofradius,whichleadstotheinpletenessoftunnelattributesandthefailureoftunnelestablishment.23.Considerthefollowingfigure.R1andR2runVRRP.VirtualIPaddressofVRRPistheinterfaceIPaddressofR1-，R1isthemaster.Requirements：R1bethemaster，priorityis200，VRRPadvertisementtimeis2s，pleasewritetheconfiguration:SupposethereareonlydefaultroutesonR1,R2，iftheuplinkinterfaceonR1getsdownandtheequipmentisinnormalconditionthenisitpossiblefortheusertorunproperly?Ifnotthenwhatkindofmeasureswillbetaken?

『圖片』答案：R1configuration：

ZXR10_R1(config)#interfacefei_1/1

ZXR10_R1(config-if)#ipaddress

ZXR10_R1(config-if)#vrrp1ip

ZXR10_R1(config-if)#vrrp1priority200

ZXR10_R1(config-if)#vrrp1advertise2

R2configuration：

ZXR10_R2(config)#interfacefei_1/1

ZXR10_R2(config-if)#ipaddress

ZXR10_R2(config-if)#vrrp1ip

ZXR10_R2(config-if)#vrrp1advertise2

Usercannotworkproperly，becauseR1isstillthemaster，whentheuplinkgetsdown,thereisnodefaultroute.WecanconfigureanotherdefaultrouterwithlowerprioritypointedtoR2onR1,orrundynamicroutingprotocolsbetweenthetworouterstomakesurethatthereisrouteonR1whentheexitisdown.24.如何控制VPLS的VFI中的用戶行為對(duì)ZXUAS設(shè)備的影響？答案：Vpls為不同vlan用戶提供了二層互通的轉(zhuǎn)發(fā)平臺(tái)，vfi與vlan進(jìn)行綁定，容易出現(xiàn)vlan中的用戶終端病毒大范圍的廣播包，可以qos來(lái)限制vfi中vlan資源的帶寬大小，同時(shí)通過(guò)vfi中的mac地址限制來(lái)控制用戶終端行為。25.TherequirementstoservicesunderUAS10600areasfollows:

1）Usersareaccessedtothesameoneradiusserverviadifferentdomainsforauthenticationandaccounting;

2）UsersareassignedwithdifferentIPaddressesanddataofusersaretransmittedthroughdifferentnetworkegresses;

Pleasedesigntherequirementstothiskindofservicetorealizethemappingbetweenuseraccountanddomain,andthemappingbetweendifferentIPaddressesandegresses.答案：UsersaccessdifferentdomainsviaSALandeachuserisassignedwithaIPaddressinhisdomain.ThususersobtainIPaddressesofdifferentvbuiinterfaces.

SincevbuiinterfaceofUAS10600doesn’tsupportpolicyrouting,it’simpossibletoforwarddatatodesignatedegressviasourceIPaddressoftheuser.

VRFmodeisadoptedonUAS10600toassociatedomain,authenticationgroup/accountinggroup,vbui,network-sideegressandroutewithcorrespondingVRF.26.描述ARP的工作過(guò)程。答案：ARP工作過(guò)程：首先源設(shè)備廣播帶有目的設(shè)備IP地址的ARP請(qǐng)求，這個(gè)網(wǎng)絡(luò)上的所有設(shè)備都會(huì)收到這個(gè)ARP請(qǐng)求。如果一臺(tái)設(shè)備發(fā)現(xiàn)請(qǐng)求中的IP地址與自己的匹配，則向源設(shè)備發(fā)送一個(gè)包含MAC地址的應(yīng)答。源設(shè)備通過(guò)這個(gè)應(yīng)答獲得目的設(shè)備的MAC地址。27.ThereisanideathataroutecanbeadvertisedtoBGPneighboraslongasthisrouteisadvertisedwithmandnetworkinBGPconfiguration.Isitright?Why?答案：Itiswrong.mandNETWORKinBGPconfigurationonlyspecifiesarangeforadvertisedroutes.Onlyrouteentrieswithinthisrange,recordedintheroutingtableandlearnedviatheotherroutingprotocols(includingdirect-connectandIGPetc.)canbeadvertisedtoitsBGPneighbors(Note:excludedefaultroute).28.請(qǐng)列舉出至少三種兩臺(tái)設(shè)備光口對(duì)接不通可能出現(xiàn)的情況及解決辦法；答案：對(duì):工作狀態(tài)不匹配，可以修改配置，使兩邊都工作在強(qiáng)制或全雙工狀態(tài)；2:光功率過(guò)強(qiáng)，在鏈路中間增加光衰；3:尾纖接錯(cuò)，收發(fā)不對(duì)應(yīng)，鴛鴦纖，可以排查線路連接；4:光模塊損壞，不發(fā)光，更換光模塊；5:端口損壞，更換端口；6:中間經(jīng)過(guò)傳輸，傳輸存在問(wèn)題，排查傳輸問(wèn)題；7:可能是軟件問(wèn)題8：可能是單板問(wèn)題29.請(qǐng)問(wèn)在BGP路由發(fā)布中，是否只要是用network命令發(fā)布的路由就一定能夠發(fā)布給BGP鄰居？答案：不是的，希望路由發(fā)布出去，首先得保證發(fā)布的路由本身存在于自己的IGP路由表中，否則不會(huì)對(duì)外宣告；30.個(gè)別撥號(hào)軟件在接入寬帶接入服務(wù)器設(shè)備進(jìn)行撥號(hào)時(shí)，其撥號(hào)進(jìn)程在PPPOE的發(fā)現(xiàn)階段被終止，可能存在哪些原因？答案：用戶的pppoe發(fā)現(xiàn)階段主要包括4個(gè)狀態(tài)：padipadopadrpads

Padi/padr由用戶發(fā)起，pado/pads由bras設(shè)備發(fā)起。

在發(fā)現(xiàn)階段的報(bào)文交互過(guò)程中,用戶與BRAS之間會(huì)交互host-uniq/ac-cookie等唯一性的標(biāo)識(shí)代碼，這些代碼在此用戶以后的pppoe發(fā)現(xiàn)和會(huì)話中作為該用戶身份的標(biāo)識(shí)別，客戶端與bras在發(fā)現(xiàn)過(guò)程中只能提取該類參數(shù)，不能修改。若撥號(hào)軟件或bras對(duì)此類參數(shù)進(jìn)行提取和修改，則會(huì)被對(duì)方認(rèn)為是非法接入，終止后期的LCP協(xié)商過(guò)程。31.請(qǐng)簡(jiǎn)述網(wǎng)絡(luò)冗余配置帶來(lái)的不利影響。Pleasebrieflydescribethedisadvangeofredundantconfigurationofnetwork答案：

A、會(huì)給網(wǎng)絡(luò)拓?fù)湓黾雍艽蟮膹?fù)雜性

A,increasetheplexityofnetworktopology

B、不能提供容錯(cuò)通信can'tprovidefault-tolerancemunication

C、成本太高，承擔(dān)不起thecostishightoafford32.Whatisthefunctionofpolicyroute?Describetheconfigurationstepsofpolicyroutebriefly.答案：policyrouteistoforwordpacketnotbasedonroutingtablebutaccordingtoadministrativestrategy.Configsteps

1）defineanACL

2）associatetheACLandIPpolicy

3）applythepolicytoaninterface33.Twodifferentdial-inuserprocesseswiththesamesessionidarepresentonRADIUSserver.Pleaseanalyzethereason.答案：Brasdeviceidentifiesthecallingaccessofeachuserviasessionidresource.Sessionidofeachon-lineuserisdifferentfromeachother,andthisparameterissenttoradiusserverasidentifierforeachuserforextractionbyradiusserver.

Sessionidisdeterminedaccordingtosystemcapacity,butthisresourceislimited,sowherethereisnotenoughidlesessionidresourceinthesystem,systemwillcallsessionidresourcebeinginusetoredistributeittoanewuser,whichmayleadtotheoccurrenceofphenomenonthattwodifferentuserswiththesamesessionidareon-lineatthesametime.Thereasonforthiskindofproblem:Largequantitiesofaccountingmessagesbeingcachedleadstocircuitresourcedistributableinsysteminadequate,sooccupycachedcircuitresource.

Thereasonforaccountingbeingcached:Poornetworkperformancecausesthataccountingmessagescan’tbeprocessedtimely;theprocessingcapabilityofradiusserver.34.請(qǐng)?jiān)敿?xì)描述OSPF的鄰居狀態(tài)及相互間的轉(zhuǎn)換過(guò)程。答案：Init：在該狀態(tài)時(shí)，OSPF路由器已經(jīng)接收到相鄰路由器發(fā)送來(lái)的Hello數(shù)據(jù)包，但自身的IP地址并沒(méi)有出現(xiàn)在該Hello數(shù)據(jù)包內(nèi)，也就是說(shuō)，雙方的雙向通信還沒(méi)有建立起來(lái)。

2-Way：這個(gè)狀態(tài)是建立交互方式真正的開(kāi)始步驟。在這個(gè)狀態(tài)，路由器看到自身已經(jīng)處于相鄰路由器的Hello數(shù)據(jù)包內(nèi)，雙向通信已經(jīng)建立。DR和BDR的選擇完成。

Exstart：這個(gè)狀態(tài)是建立交互狀態(tài)的第一個(gè)步驟。在這個(gè)狀態(tài)，路由器要決定用于數(shù)據(jù)交換的初始的數(shù)據(jù)庫(kù)描述數(shù)據(jù)包的序列號(hào)，以保證路由器得到的永遠(yuǎn)是最新的鏈路狀態(tài)信息。同時(shí)，在這個(gè)狀態(tài)路由器還必須決定路由器之間的主備關(guān)系，處于主控地位的路由器會(huì)向處于備份地位的路由器請(qǐng)求鏈路狀態(tài)信息。

Exchange：在這個(gè)狀態(tài)，路由器向相鄰的OSPF路由器發(fā)送數(shù)據(jù)庫(kù)描述數(shù)據(jù)包來(lái)交換鏈路狀態(tài)信息，每一個(gè)數(shù)據(jù)包都有一個(gè)數(shù)據(jù)包序列號(hào)。

Loading：在loading狀態(tài)，OSPF路由器會(huì)就其發(fā)現(xiàn)的相鄰路由器的新的鏈路狀態(tài)數(shù)據(jù)及自身的已經(jīng)過(guò)期的數(shù)據(jù)向相鄰路由器提出請(qǐng)求，并等待相鄰路由器的回答。

Full：這是兩個(gè)OSPF路由器建立交互關(guān)系的最后一個(gè)狀態(tài)，在這時(shí)，建立起交互關(guān)系的路由器之間已經(jīng)完成了數(shù)據(jù)庫(kù)同步的工作，它們的鏈路狀態(tài)數(shù)據(jù)庫(kù)已經(jīng)一致。35.簡(jiǎn)述MPLSTEFRR產(chǎn)生的背景?答案：FRR（FastRerouting）快速重路由是MPLS流量工程的一個(gè)重要功能，是對(duì)RSVPTE子系統(tǒng)的功能增強(qiáng)。對(duì)于復(fù)雜的網(wǎng)絡(luò)，經(jīng)常會(huì)出現(xiàn)鏈路或者節(jié)點(diǎn)的失效。傳統(tǒng)的處理方法是由IGP處理，對(duì)網(wǎng)絡(luò)拓?fù)溥M(jìn)行重新匯聚，快速產(chǎn)生路由。對(duì)于大型網(wǎng)絡(luò)來(lái)說(shuō)，拓?fù)涞膮R聚需要相當(dāng)長(zhǎng)的時(shí)間，一般為秒級(jí)，用戶數(shù)據(jù)丟失比較嚴(yán)重。

對(duì)于這種情況，我們可以通過(guò)MPLSTE的FRR功能最大限度地減少分組丟失，F(xiàn)RR功能可以在幾十毫秒時(shí)間內(nèi)，將分組從失效鏈路切換到備份鏈路，大大減少分組的丟失。同時(shí)滿足一定的資源要求。36.Howdodifferentusersinthesamedomainhavedifferentbandwidthratelimit?Pleasegivesomedetailedmethods.答案：1）Whenuserdialsandaccessesradiusserverforauthenticationandaccountingwithoutdomainname,brascansetdomainwithdifferentbandwidthsandspecifydifferentbandwidthlimitstousersindifferentdomains.

2）Whenuserdialsupforauthenticationwithdomainname,radiusservercansetdifferentratesfordifferentaccounts.

3）DSLAMlimitsratesontheportfordifferentusers.37.InIS-IS,circuitIDis0000.0c76.5b7c.02.Whatareitscontents?答案：systemIDis0000.0c76.5b7c

PseudonodeIDis02,interfaceisinabroadcastsubnetworkorNBMAsubnetwork.38.如圖所示，T160G-1，T160G-2，T64G組成的網(wǎng)絡(luò)如下，現(xiàn)要求在T64G上實(shí)現(xiàn)上行鏈路的備份，即T160G-1和T64G的鏈路發(fā)生故障，需要切換到T160-2和T64G的鏈路上，反之亦然。請(qǐng)問(wèn)如何通過(guò)ZESR來(lái)實(shí)現(xiàn)此功能？答案：將T160G-1，T160G-2，T64G規(guī)劃成一個(gè)分段，即從環(huán)，將T64G規(guī)劃成master節(jié)點(diǎn)即可。這樣，正常情況下，會(huì)阻塞T64G和T160G-1或者T160G-2之間的鏈路，當(dāng)鏈路出現(xiàn)linkdown或者通過(guò)link-hello檢測(cè)超時(shí)，則會(huì)觸發(fā)ZESR切換，從而業(yè)務(wù)也切換到另外一條鏈路。39.請(qǐng)簡(jiǎn)述二層網(wǎng)絡(luò)冗余配置帶來(lái)的不利影響。答案："1、會(huì)給網(wǎng)絡(luò)拓?fù)湓黾雍艽蟮膹?fù)雜性

2、容易造成二層環(huán)路

3、成本太高，承擔(dān)不起"40.TellRIPprotocolversionsandwhataretheirdifferences?答案：1.RIPv1,RIPv2;

2.V2deliverspacketsbywayofmulticast;

3.V2supportsvlsm;

4.AuthenticationisaddedtoV241.AssumethatthereisaClassCaddress/24fornetworkofapany.Atfirstthereareonlytwodepartmentsusingofficenetworkofthepany,wherefinancialdepartmentAhas50hostsandPRdepartmentBhas60hosts.panyusesZXR103928asroutingswitch,plansIPaddress/26fordepartment

A,correspondingtoVLAN-100withgatewaytobe,andplansIPaddress00/26fordepartment

B,correspondingtoVLAN101withgatewaytobe93.Nowanothertwodepartments(HRdepartmentCandmarketingdepartmentD)needtobeaccessedintheofficenetwork,wheredepartmentChas40hostsanddepartmentDhas80hosts.Toensurenetworksecurity,eachdepartmentshallcorrespondtooneVLAN,wheredepartmentCcorrespondstoVLAN102anddepartmentDcorrespondstoVLAN103.Thequestionishowtorealizethisconfigurationon3928.Pleasegiveyourideasandtheconfigurationon3928.答案：Enablesupervlanon3928.CandDdepartmentsusetheaddressofSUPERVLANasgatewayaddress,andtheSUPERVLANcorrespondstoIPnetworksegment:4/25,with126hostaddressesavailableintotalandgatewayaddresstobe5/25.Forthis,theconfigurationisasfollows:

ZXR10_A(config)#interfacesupervlan1

ZXR10_A(config-int)#ipaddress528

ZXR10_A(config-int)#exit

/*把SubVLAN加入到SuperVLAN*/

ZXR10_A(config)#vlan102

ZXR10_A(config-vlan)#supervlan1

ZXR10_A(config-vlan)#exit

ZXR10_A(config)#vlan103

ZXR10_A(config-vlan)#supervlan1

ZXR10_A(config-vlan)#exit

/*SetthatdepartmentCaccesses3928viaFEI_1/5anddepartmentDaccesses3928viaFEI_1/6*/

ZXR10_A(config)#interfacefei_1/5

ZXR10_A(config-int)#switchmodetrunk

ZXR10_A(config-int)#switchtrunkvlan102

ZXR10_A(config)#interfacefei_1/6

ZXR10_A(config-int)#switchmodetrunk

ZXR10_A(config-int)#switchtrunkvlan10342.Pleaselistatleastthreeprobabiliteswhentwoequiomentcannotinterconnectwitheachtoherviaopticalinterfaes,andthenpleasegivesolutionsrespectively:答案：對(duì).theworkingstatusisnotmatch,theconfigurationcanbechanged,sothebothendscanworkinforceortheirconfigurationscanbechangedtofullduplexmodes;2Theopticalpoweristoolarge.addopticalattenuatorinthelink;3.Thetailfiberisinstalledinawrongwaywhichcausesdisorderedinfosendingandreception.A-Wirecontactsearth,B-Wirecontactsbattery,socheckthecabling4.Theopticalmoduleisdamaged.Changetheopticalmodule;5.Theportisdamaged.changetheport.6.Thetransmissionsectionhasproblems.checkthetransimissionsection;7.Thesoftwaremayhaveproblems.8.Themodulemayhaveproblems43.點(diǎn)到多點(diǎn)網(wǎng)絡(luò)與NBMA網(wǎng)絡(luò)在ospf有關(guān)DR和BDR選舉方面最本質(zhì)的區(qū)別是什么？答案：在點(diǎn)到多點(diǎn)的網(wǎng)絡(luò)中不選舉DR、BDR。44.組網(wǎng)：R1--R2--R3--R4；R1,R2,R3運(yùn)行在MPLS域中，R4不運(yùn)行MPLS，請(qǐng)問(wèn)在R3上查看標(biāo)簽表時(shí)候，對(duì)于R4的loopback地址()，R3的出標(biāo)簽是3嗎？如果不是，請(qǐng)問(wèn)如何使該標(biāo)簽為3？答案：R3給R4的loopback地址分配的標(biāo)簽不是3，因?yàn)槿笔∏闆r下，LDP只為直連網(wǎng)段分配彈出標(biāo)簽，并向?qū)Φ萀SR通告；如果希望分配的標(biāo)簽為3，可以在R3上配置如下：R3(config)#ipaccess-liststandard1

R3(config-std-nacl)#permit

R3(config-std-nacl)#exit

R3(config)#mplsldpegressnexthop145.簡(jiǎn)述建立生成樹(shù)的幾個(gè)步驟。BrieflydescribethestepstoconfigurateSTP答案：

A、選擇根網(wǎng)橋toelectrootbridge

B、選擇根端口toelectrootport

C、選擇指定端口toelectdesignatedport

D、改變端口狀態(tài)tochangeportstate46.簡(jiǎn)述以下在VRF下做策略路由的簡(jiǎn)要步驟。答案：1.配置ACL匹配需要做策略路由的數(shù)據(jù)包

2.配置ROUTER-MAP對(duì)于匹配的數(shù)據(jù)包設(shè)置有效的下一跳

3.將該策略路由應(yīng)用到VRF接口上47.一個(gè)MPLSBGP/VPN的組網(wǎng)：PEAPEBPEC；目的，PEB可以和PEA,PEC業(yè)務(wù)互通，PEA和PEC之間不能互通，那么該如何設(shè)置RT，請(qǐng)舉例說(shuō)明答案：舉例：RB的importRT：200:1exportRT：100:1；RA和RC的importRT：100:1exportRT：200:1；即可48.ZXUAS系列對(duì)限制用戶帳號(hào)訪問(wèn)網(wǎng)站，有幾種實(shí)現(xiàn)方式？分別如何實(shí)現(xiàn)？答案：對(duì)）對(duì)domain中應(yīng)用ACL，控制該domain下的所有撥號(hào)用戶訪問(wèn)的目的IP；

2）在網(wǎng)絡(luò)層接口應(yīng)用ACL，對(duì)用戶訪問(wèn)的目的IP進(jìn)行控制；

3）在vbui接口下應(yīng)用ACL，對(duì)此vbui下的網(wǎng)段用戶訪問(wèn)進(jìn)行限制；

4）Radius服務(wù)器下對(duì)撥號(hào)用戶下發(fā)ACL的服務(wù)等級(jí)，限制用戶訪問(wèn)49.在做NAT轉(zhuǎn)換的時(shí)候，如果公網(wǎng)的IP地址很少，那么應(yīng)該啟用NAT還是PAT?答案：應(yīng)該啟用PAT50.請(qǐng)問(wèn)下面的這個(gè)as－pathlist是什么含義：ipas-pathaccess-list10permit^$？答案：通過(guò)as－path屬性來(lái)過(guò)濾路由，只允許通告自己AS發(fā)布的路由51.列舉OSPF協(xié)議的報(bào)文類型。答案：HELLO報(bào)文、DD報(bào)文、LSR報(bào)文、LSU報(bào)文、LSACK報(bào)文。52.23portof2826Sisaddedtovlan100bywayofuntagandconnectedtooneserver;24portisanuplinkport,connectedtoT64Gandaddedtomultiplevlans(includingvlan100)bywayoftag.Requirements:

1.Seton2826Sthatvlan100hasthehighestpriority.Pleasetelltheconfigurationof2826S;

2.IfitcansetonT64Gtoothatvlan100hasthehighestprioritywithoutadditionalconfiguration?Ifisnotfeasible,pleasetelltheconfigurationmustbeadded;ifitisfeasible,pleasetellthereason.答案：1.setport24vlan-priorityenable，setvlan100priorityon7

2.Yes,itcan.Since24portisatagportofvlan100,priorityofthemessageinvlan100sentoutfromthisporthasbeenspecifiedinpriorityfieldofvlantag.Thisprioritywillapplyifnootherspecialconfigurationisgiven.53.Whenaccessingbroadbandaccessserverdevicefordialup,thedialingprocessofindividualdial-upsoftwareisterminatedatPPPOEdiscoverystage.Pleaseanalyzeprobablereasons.答案：TherearefourstatesatPPPOEdiscoverystage:padipadopadrpads

Padi/padrisestablishedbyuserandpado/padsisestablishedbybrasdevice.

AfterBrasreceivesdial-inrequestfromauser,uniqueidentifiercodessuchashost-uniq/ac-cookiewillbeassignedtothisuserinpado.Thesecodeswillactasuseridentifiersinthefollowingpppoediscoveryandsessionofthisuser.Clientandbrascanonlyextractthiskindofparametersduringthediscoveryprocesswithoutmodification.Ifdial-upsoftwareorbrasextractsandmodifiesthiskindofparameters,itwillberegardedasunauthorizedaccessandthefollowingLCPnegotiationprocesswillbeterminated.54.ZXUAS系列設(shè)備下二層接入設(shè)備的網(wǎng)管可以由幾種接入方式？請(qǐng)簡(jiǎn)述這幾種接入方式的區(qū)別。答案：分為固定IP（iphost）方式和路由方式接入。Iphost方式接入時(shí)，BRAS對(duì)此類用戶管理類似于supervlan，各個(gè)網(wǎng)管IP之間缺省隔離。路由方式接入需要浪費(fèi)多個(gè)IP作為網(wǎng)段地址和廣播地址，各個(gè)網(wǎng)管IP之間可通過(guò)路由轉(zhuǎn)發(fā)方式進(jìn)行訪問(wèn)。55.TransmitIGPcostvalueinner-ASasBGPMEDvaluesoastoinfluenceroutingwithinneighboringASs.Pleaseanalyzestrengthandshortingofthisroutingpolicy.答案：Strength:Itcanensurethatthedirectedtrafficcanbetransmittedviatheshortestpathinner-ASonthedevicewhichisdeployedwiththispolicy.

Shorting:Thetopologychangesinner-ASwillaffecttheIGPcostsoastoaffectroutingonthedeviceinpeerAS.56.說(shuō)明SVLANvfp添加外層標(biāo)簽的過(guò)程答案：首先，數(shù)據(jù)包進(jìn)入custoemr端口，根據(jù)nativevlan添加外層標(biāo)簽，然后再在customer接口根據(jù)vfpsession去匹配，如果匹配上，則替換成對(duì)應(yīng)的外層標(biāo)簽。57.ZXR10中LDPFRR在IGP為OSPF環(huán)境下計(jì)算備份路徑的方式？答案：ZXR10提供兩種備份路由計(jì)算策略：1，滿足基本鏈路保護(hù)類型的一種路由備份方式，即備份節(jié)點(diǎn)到達(dá)源節(jié)點(diǎn)的距離與源節(jié)點(diǎn)到達(dá)目的節(jié)點(diǎn)的距離之和必須大于該備份節(jié)點(diǎn)到達(dá)目的節(jié)點(diǎn)的距離。2，滿足更為嚴(yán)格的Down-streamPath的路由備份方式，其要求備份下一跳到達(dá)目的節(jié)點(diǎn)的距離必須小于源節(jié)點(diǎn)到達(dá)目的節(jié)點(diǎn)的距離。58.簡(jiǎn)述UAS中L2TP方式的VPN處理流程。答案：Vpn用戶發(fā)起請(qǐng)求，LAC（UAS）將請(qǐng)求發(fā)送到radius上認(rèn)證，認(rèn)證成功與LNS建立L2TP隧道，之后進(jìn)入會(huì)話流程。59.在MPLSVPN網(wǎng)絡(luò)中，現(xiàn)要實(shí)現(xiàn)對(duì)VPNA的某一條路由設(shè)置其export的RT屬性為100:100，該VPN的其他路由使用100:200的路由屬性，請(qǐng)問(wèn)該如何配置？給出配置思路即可答案：1.首先需要配置一條ACL來(lái)匹配這條路由條目：

Aclstandardnumber1

Permitx.x.x.xx.x.x.x

2.配置route-map，設(shè)置與該ACL匹配的路由前綴的RT值為100:100

Route-mapvpnexportpermit10

Matchipaddress1

Setextmunityrt100:100

3.配置該VPN對(duì)應(yīng)的VRF，設(shè)置該VRF的EXPORTRT為100:200，同時(shí)通過(guò)使用exportmapvpnexport來(lái)對(duì)特定的路由實(shí)現(xiàn)EXPORTRT的設(shè)置。

IpvrfVPNA

Rd100:200

Route-targetimport100:200

Route-targetexport100:200

Exportmapvpnexport60.GiveabriefintroductionthathowBGPprotocolavoidsloopviaAS_PATHattribute.答案：WhenarouterrunningBGPestablishesarouteandadvertisesitwithinlocalAS,itwilladditsASnumbertoAS_Path.Whenadvertisingroutestoexternalpeers,thesesubsequentBGPswilladdtheirASnumberstotheirAS_Pathattributes.Thus,AS_PathgivestheinformationaboutASthatwillbepassedthroughforreachingNLRI.IfaBGProuterreceivesaroutefromexternalpeerwithitsownASnumberencapsulatedintheAS_Pathattributeofthisroute,thisBGProuterwillknowthatitisalooproute,andwilldroptheroutetoavoidloop.61.Ifbothlayer2VPNandlayer3VPNcansatisfythedemandsofuser,whichVPNisremendedforlargecarriercross-cityapplication?Why?答案：Layer3VPNisremendedforusersinusualcases,sincelayer3VPNcarrierhasastrongercapabilityincontrollingandmanagingVPN,layer3VPNhasabetterscalability,andtheremaybeproblemsfordeviceofadifferentmanufacturertointerconnectwithlayer2VPN,afterallthereisnoRFCspecificationforlayer2VPNanddifferentmanufacturershavedifferentrealizingmechanisms,whichleadtorelativelyhighrisksfordevelopingservices.62.HowtofilterCISCOPVATpacketonZXR10T64GandZXR103900seriesswitches.答案：(1)DefineL2ACL:

Acllinknumber201

Rule1denyanyingressanyegress0100.0ccc.cccd0000.0000.0000

Rule2permitanyingressanyegressany

!

(2)ApplyACLtocorrespondinginterfaces63.當(dāng)鏈路發(fā)生故障，網(wǎng)絡(luò)的拓?fù)浒l(fā)生改變，新的配置消息總要經(jīng)過(guò)一定的時(shí)延才能傳遍整個(gè)網(wǎng)絡(luò)，在什么情況下會(huì)造成網(wǎng)絡(luò)暫時(shí)失去連通性?When答案：在舊的拓?fù)渲斜蛔枞亩丝趹?yīng)該在新的拓?fù)渲袇⑴c數(shù)據(jù)轉(zhuǎn)發(fā)，如果它自己不知道，則會(huì)造成網(wǎng)絡(luò)暫時(shí)失去連通性。64.一個(gè)MPLSBGP/VPN的組網(wǎng)：PEAPEBPEC；目的，PEB可以和PEA,PEC業(yè)務(wù)互通，PEA和PEC之間不能互通，那么該如何設(shè)置RT，請(qǐng)舉例說(shuō)明；答案：舉例：RB的importRT：200:1exportRT：100:1；RA和RC的importRT：100:1exportRT：200:1；即可65.簡(jiǎn)述路由反射器的運(yùn)作原理。答案：反射體Reflector接受到來(lái)自終端clients和非終端nonclients的更新updates

如果更新update是來(lái)自終端—反射到終端和非終端(除去產(chǎn)生者)

如果更新update是來(lái)自非終端—反射到終端

如果更新update是來(lái)自EBGPpeer—反射到所有的終端和非終端66.請(qǐng)問(wèn)高端路由器V2821版本之后，BGP中使用network命令通告路由的規(guī)則是怎樣的？答案：network命令通告路由時(shí)，采用精確匹配的原則，只有和配置的地址，掩碼完全相同才認(rèn)為是匹配上從而向鄰居通告。67.Pleasedescribethedifferencebetweenstaticbindinganddynamicbinding.答案：Staticbindingwillbindinterfacewithstaticipaddress,suchasfixed-linesubscribers.Dynamicbiddingwillassignipaddressdynamicly,suchaspppoedialupsubscribers.68.試分析設(shè)備上出現(xiàn)如下告警的可能原因是什么？應(yīng)該如何排查問(wèn)題？

Analarm17419level6occurredat00:39:1403/02/2007UTCsentbyMEC1%OSPF%anOSPFpackethasbeenretransmittedonanonvirtualinterfaceretransmitpktonintf2答案：這種告警說(shuō)明OSPF報(bào)文存在重傳的情況；可能的情況有：

1、IP層以下存在丟包情況；

2、對(duì)端設(shè)備對(duì)于OSPF報(bào)文處理不過(guò)來(lái)。排查和解決辦法：

1、重點(diǎn)檢查鏈路層的狀態(tài)是否正常，端口有無(wú)CRC錯(cuò)誤等，也可以通過(guò)PING大包觀察；

2、對(duì)端設(shè)備是否CPU高，導(dǎo)致報(bào)文處理不過(guò)來(lái)，也可以了解對(duì)端設(shè)備性能是否能支持該網(wǎng)絡(luò)中的路由條目，如果不支持則需要升級(jí)或替換設(shè)備解決。69.STP的保護(hù)功能包括哪些內(nèi)容？答案：STP的保護(hù)功能包括了端口的BPDU保護(hù)、根交換機(jī)保護(hù)以及環(huán)路保護(hù)。70.Followingnetworkdevicescanbefoundinanetwork:twosetsofT64G,twofirewalls,andtwosetsofserverfarm.Takingstability,safeguard,andefficiencyofnetworkintoaccount,pleasedesignnetworkingdiagramandconfigurationdraftwithrequirementsasfollows:1.Forserverfarm1,thetotaltrafficissmallbutitrequiresafairlyhighsafety;

2.Forserverfarm2,thetrafficislarge,eachservershallbeconfiguredwitha1000Mnetworkinterface,andthebuilt-inserverfirewallisabletomeetrequirementsinsafety;

3.Firewallisofmaster-slaveconfiguration,withfloatingaddressofinsideinterfaceasthegatewayofupstreamdeviceandonlyonegatewayisneededforoutsideinterface.答案：Serverfarm1requiresafairlyhighsafety,soaprofessionalfirewallisneededforsafeguard,i.e.serverfarm1reachesexternalnetworkafterpassingthroughfirewall;serverfarm2hasnospecialrequirementstosafetyanditrequiresalargetraffic,soweonlyneedtoconnectittoT64Gdirectly,thentoexternalnetwork;topulsorilyrequirethatserverfarm1reachesexternalnetworkafterpassingthroughfirewall,dataofserverfarm1shallbedeliveredto內(nèi)口offirewallvialayer2transparenttransmissionwithfloatingaddressofinsideinterfaceasthegateway.Meanwhilesincefirewallifofmaster/slaveconfiguration,thegatewayofitsoutsideinterfacecanonlybeanIPaddress,therefore,VRRPneedstobeenabledbetweenT64Gs.ToimproveinterconnectionstabilityofT64G,smartgroupshallbeconfiguredforatleasttwoportinterconnectionsbetweenT64Gs.Itisoktoenablemonlayer3onserverfarm2.71.Brieflydescribetheformationprocessoflabelswitchingpath(LSP)inMPLSnetwork.答案：Eachnodecreatesitsownroutingtableunderthefunctionofroutingprotocols(e.g.BGP,OSPF,IS-ISetc.)afternetworklaunching;Eachnodecreateslabelinformationbase(LIB)underthecontrolofLDPaccordingtoroutingtable;MapandbineiningandoutgoinglabelsoninletLSR,middleLSRandoutletLSR,thusformingaLSP.72.Asshowninthefigure,ZXR10GERinterfacefei_1/3isconnectedtoBASUNI,interfacefei_1/4isconnectedtoBASNNI.,PPPoEusersareconnectedtoZXR10GERinterfacefei_1/1，leased-lineusersareconnectedtointerfacefei_1/2.PPPoEusersareinVLAN10～19，BASUNIVLANIDrangeis20～29；leased-lineusersareinVLAN30～31。PleasewriteGERconfiguration.

『圖片』答案：ZXR10(config)#interfacefei_1/3

ZXR10(config-if)#ipforwarding-modevlan-switch

ZXR10(config)#interfacefei_1/1

ZXR10(config-if)#ipforwarding-modevlan-switch

ZXR10(config)#vlan-forwardingingressfei_1/110egressfei_1/320

ZXR10(config)#vlan-forwardingingressfei_1/111egressfei_1/321

ZXR10(config)#vlan-forwardingingressfei_1/112egressfei_1/322

ZXR10(config)#vlan-forwardingingressfei_1/113egressfei_1/323

ZXR10(config)#vlan-forwardingingressfei_1/114egressfei_1/324

ZXR10(config)#vlan-forwardingingressfei_1/115egressfei_1/325

ZXR10(config)#vlan-forwardingingressfei_1/116egressfei_1/326

ZXR10(config)#vlan-forwardingingressfei_1/117egressfei_1/327

ZXR10(config)#vlan-forwardingingressfei_1/118egressfei_1/328

ZXR10(config)#vlan-forwardingingressfei_1/119egressfei_1/329

ZXR10(config)#interfacefei_1/4

ZXR10(config-if)#ipaddress52

ZXR10(config)#interfacefei_1/2.30

ZXR10(config-subif)#encapsulationdot1q30

ZXR10(config-subif)#ipaddress92

ZXR10(config)#interfacefei_1/2.31

ZXR10(config-subif)#encapsulationdot1q31

ZXR10(config-subif)#ipaddress59273.AfteratypicalIPnetworkissetupandconfigured,usersreflectthattheyfailtoopenpartsofwebpagesonawebsiteanddownloadlargesizedocumentsfromthiswebsiteinwayofFTP;weknowthattheaddressofthiswebsiteis,wecanpingthewebsitefromuserPCsuccessfullybyexecutingmandping,butfailtopingthewebsitebyexecutingmandping–11500-f.Pleaseanalyzethereason.答案：TheMTUofalinktotheserveristoosmall,andlargesizepacketswithoutfragmentationcan’tpassthrough.OnPC,smallsizepacketof64bytesisdefaultforpingaction,andpingactionissuccessfulaslongthesizeofpacketissmallerthanMTUvalueofthislink.Inthiscase,thepacketsareof1500bytesspecifiedby-1andfragmentationisforbiddenspecifiedby–f,sowecan’tpingthewebsitesuccessfully.74.DescribetheestablishmentofLDPsessionanditsmaintenanceprocess.答案：1.BeforetheestablishmentofLDPsession,routerwillsendmulticasthellomessagestoitsinterfaceswhereLDPisenabled,andmeanwhiletheseinterfaceswilllistenLDPhellomessagesinrealtimetodiscoverneighbors;

2.Afterreceivinghellomessages,routerwilljudgeifsessionhasbeenestablishedwithpeer;ifthesessionhasn’tbeenestablished,itwillstartsessionconnectionpreparationprocess.Atfirst,routerselectsMaterinitiatoraccordingtoIPaddressesofinterfaces,wheretheinterfacewithalargerIPaddresswillbeselectedasinitiatortoestablishTCPconnection;

3.Theinitiatorsendsinitmessagetoestablishthesessionwithnegotiationparameteretc.carriedinthemessage;

4.Afterreceivinginitmessagesentformtheinitiator,thepassivesidewillcheckthenego