Encor new questions考試認證題庫

Question1

AfteraredundantrouteprocessorfailureoccursonaLayer3device,whichmechanismallowsforpacketstobeforwardedfromaneighboringrouterbasedonthemostrecenttables?

A.RPVST+

B.RPfailover

C.BFD

D.NSF

Answer:

D

Question2

WhatisthedifferencesbetweenTCAMandtheMACaddresstable?

A.RouterprefixlookupshappensinCAM.MACaddresstablelookupshappeninTCAM

B.TheMACaddresstablesupportspartialmatches.TCAMrequiresanexactmatch

C.TheMACaddresstableiscontainedinCAM.ACLandQoSinformationisstoredinTCAM

D.TCAMisusedtomakeLayer2forwardingdecisions.CAMisusedtobuildroutingtables

Answer:

C

Explanation

Whenusing

TernaryContentAddressableMemory

(TCAM)insideroutersit’susedforfasteraddresslookupthatenablesfastrouting.

Inswitches

ContentAddressableMemory

(CAM)isusedforbuildingandlookupofmacaddresstablethatenablesL2forwardingdecisions.

BesidesLongest-PrefixMatching,TCAMintoday’sroutersandmultilayerSwitchdevicesareusedtostoreACL,QoSandotherthingsfromupper-layerprocessing.

Question3

WhichtwosouthboundinterfacesoriginatefromCiscoDNACenterandterminateatfabricunderlayswitches?(Choosetwo)

A.UDP67:DHCP

B.ICMP:Discovery

C.TCP23:Telnet

D.UDP162:SNMP

E.UDP6007:NetFlow

Answer:

BD

Explanation

Inthefigurebelow,wecanseeICMP&SNMPcanreachtounderlayswitches.

Question4

Whatisthefunctionofacontrol-planenodeinaCiscoSD-Accesssolution?

A.toconnectAPsandwirelessendpointstotheSD-Accessfabric

B.toconnectexternalLayer3networkstotheSDAccessfabric

C.toimplementpoliciesandcommunicatewithnetworksoutsidethefabric

D.torunamappingsystemthatmanagesendpointtonetworkdevicerelationships

Answer:

D

Explanation

Control-PlaneNodes

–MapSystemthatmanagesEndpointtoDevicerelationships

FabricBorderNodes–AFabricdevice(e.g.Core)thatconnectsExternalL3network(s)totheSDAFabric

FabricEdgeNodes–AFabricdevice(e.g.AccessorDistribution)thatconnectsWiredEndpointstotheSDAFabric

FabricWirelessController–AFabricdevice(WLC)thatconnectsAPsandWirelessEndpointstotheSDAFabric

Reference:

/c/dam/m/hr_hr/training-events/2019/cisco-connect/pdf/VH-Cisco-SD-Access-Connecting.pdf

Question5

Refertotheexhibit.WhatistheresultwhenaswitchthatisrunningPVST+isaddedtothisnetwork?

A.Spanningtreeisdisabledautomaticallyonthenetwork

B.DSW2operatesinRapidPVST+andthenewswitchoperatesinPVST+

C.BothswitchesoperateinthePVST+mode

D.BothswitchesoperateintheRapidPVST+mode

Answer:

B

Explanation

FromtheoutputweseeDSW2isrunninginRSTPmode(infactRapidPVST+modeasCiscodoesnotsupportRSTPalone).WhenanewswitchrunningPVST+modeisaddedtothetopology,theykeeprunningtheoldSTPinstancesasRSTP(infactRapidPVST+)iscompatiblewithPVST+.

Question6

Whatisacharacteristicofanext-generationfirewall?

A.requiredineachlayerofthenetwork

B.filterstrafficusingLayer3andLayer4informationonly

C.onlyrequiredatthenetworkperimeter

D.providesintrusionprevention

Answer:

D

Explanation

Anextgenerationfirewalladdsadditionalfeaturessuchasapplicationcontrol,integrated

intrusionprevention

(IPS)andoftenmoreadvancedthreatpreventioncapabilitieslikesandboxing.

Question7

WhichmeasureisusedbyanNTPservertoindicateitsclosenesstotheauthoritativetimesource?

A.stratum

B.hopcount

C.timezone

D.latency

Answer:

A

Explanation

Thestratumlevelsdefinethedistancefromthereferenceclock.Areferenceclockisastratum0devicethatisassumedtobeaccurateandhaslittleornodelayassociatedwithit.Stratum0serverscannotbeusedonthenetworkbuttheyaredirectlyconnectedtocomputerswhichthenoperateasstratum-1servers.Astratum1timeserveractsasaprimarynetworktimestandard.

Astratum2serverisconnectedtothestratum1server;thenastratum3serverisconnectedtothestratum2serverandsoon.Astratum2servergetsitstimeviaNTPpacketrequestsfromastratum1server.Astratum3servergetsitstimeviaNTPpacketrequestsfromastratum-2server…

Question8

WhichtworesultsoccurifCiscoDNACenterlosesconnectivitytodevicesintheSD-Accessfabric?(Choosetwo)

A.AlldevicesreloadafterdetectinglossofconnectiontoCiscoDNACenter

B.Alreadyconnectedusersareunaffected,butnewuserscannotconnect

C.Usersloseconnectivity

D.CiscoDNACenterisunabletocollectmonitoringdatainAssurance

E.Userconnectivityisunaffected

Answer:

DE

Explanation

IfyouhaveCiscoSD-AccessimplementedandDNACenterbecomesunreachablethenthewiredandwirelessnetworkwillcontinuetoforwardpacketsasusual.Therewillbenoimpacttonetworkperformanceorbehavior.YesyouwillbeabletoSSH/telnet/consoleintoswitchesandwirelessnetworkinfrastructureasusual.FortheperiodDNACenterisunreachable,Assurancedatawillbelost,andyouwillnotbeabletomakeconfigurationchangestotheCiscoSD-Accessnetwork.

Question9

WhichtwocomponentsaresupportedbyLISP?(Choosetwo)

A.proxyETR

B.HMACalgorithm

C.routereflector

D.egresstunnelrouter

E.spoke

Answer:

AD

Explanation

AnEgressTunnelRouter(ETR)connectsasitetotheLISP-capablepartofacorenetwork(suchastheInternet),publishesEID-to-RLOCmappingsforthesite,respondstoMap-Requestmessages,anddecapsulatesanddeliversLISP-encapsulateduserdatatoendsystemsatthesite.

ALISPproxyETR(PETR)implementsETRfunctionsonbehalfofnon-LISPsites.APETRistypicallyusedwhenaLISPsiteneedstosendtraffictonon-LISPsitesbuttheLISPsiteisconnectedthroughaserviceproviderthatdoesnotacceptnonroutableEIDsaspacketsources.PETRsactjustlikeETRsbutforEIDsthatsendtraffictodestinationsatnon-LISPsites.

Question10

Draganddropthevirtualcomponentfromtheleftontotheirdescriptionsontheright.

Answer:

+configurationfilecontainingsettingsforavirtualmachinesuchasguestOS:VMX

+componentofavirtualmachineresponsibleforsendingpacketstothehypervisor:vNIC

+zipfilecontainingavirtualmachineconfigurationfileandavirtualdisk:OVA

+filecontainingavirtualmachinediskdrive:VMDK

Explanation

TheVMXfilesimplyholdsthevirtualmachineconfiguration.

VMDK(shortforVirtualMachineDisk)isafileformatthatdescribescontainersforvirtualharddiskdrivestobeusedinvirtualmachineslikeVMwareWorkstationorVirtualBox.

AnOVAfileisanOpenVirtualizationAppliancethatcontainsacompressed,“installable”versionofavirtualmachine.WhenyouopenanOVAfileitextractstheVMandimportsitintowhatevervirtualizationsoftwareyouhaveinstalledonyourcomputer.

Question11

HowdoesEIGRPdifferfromOSPF?

A.EIGRPismorepronetoroutingloopsthanOSPF

B.EIGRPsupportsequalorunequalpathcost,andOSPFsupportsonlyequalpathcost.

C.EIGRPhasafullmapofthetopology,andOSPFonlyknowsdirectlyconnectedneighbors

D.EIGRPusesmoreCPUandmemorythanOSPF

Answer:

B

Explanation

BothEIGRPandOSPFisnotsusceptibletoroutingloopsandEIGRPisnotmorepronetoroutingloopsthanOSPF->AnswerAisnotcorrect.

BothEIGRPandOSPFhasafullmapofthetopology->AnswerCisnotcorrect.

OSPFmaintainsinformationaboutallthenetworksandrunningroutersinitsarea.Eachtimethereisachangewithinthearea,allroutersneedtore-synctheirdatabaseandthenrunSPFagain.ThisprocessmakesitmoreCPUintensive.EIGRP,ontheotherhand,hastriggeredandincrementalupdates.ThereforeEIGRPismoreefficientintermsofCPUusageandmemory.

Question12

Refertotheexhibit.

Whatdoestheoutputconfirmabouttheswitch’sspanningtreeconfiguration?

A.Thespanning-treemodestpieeecommandwasenteredonthisswitch

B.Thespanning-treeoperationmodeforthisswitchisPVST

C.Thespanning-treeoperationmodeforthisswitchisIEEE

D.Thespanning-treeoperationmodeforthisswitchisPVST+

Answer:

D

Explanation

Thedefaultspanning-treemodeinCiscoswitchisPVST+.Thisspanning-treemodeisbasedontheIEEE802.1DstandardandCiscoproprietaryextensions.PVST+issameasstandardIEEE802.1DbutitrunsoneachVLAN.Intheoutputweseetheline“Spanningtreeenabledprotocolieee”under“VLAN20”soitcansaytheswitchisrunninginPVST+mode.

Question13

AcustomerhasrecentlyimplementedanewwirelessinfrastructureusingWLC-5520SatasitedirectlynexttoalargecommercialairportUsersreportthattheyintermittentlyloseWi-Ficonnectivity,andtroubleshootingrevealsitisduetofrequentchannelchanges.Whichtwoactionsfixthisissue?(Choosetwo)

A.RemoveUNII-2andExtendedUNII-2channelsfromthe5GHzchannellist

B.RestoretheDCAdefaultsettingsbecausethisautomaticallyavoidschannelinterference

C.DisableDFSchannelstopreventinterferencewithDopplerradar

D.EnableDFSchannelsbecausetheyareimmunetoradarinterference

E.ConfigurechannelsontheUNII-2andtheExtendedUNII-2sub-bandsofthe5GHzbandonly

Answer:

AC

Explanation

Inthe5GHzspectrumsomeofthechannelsusedby802.11aresubjecttoDynamicFrequencySelection(DFS)requirements.ThisisduetoourclientscoexistencewithotherRFtechnologiessuchasMaritime,AviationandWeatherRADAR.

DynamicFrequencySelection(DFS)istheprocessofdetectingradarsignalsthatmustbeprotectedagainstinterferencefrom5.0GHz(802.11a/h)radios,andupondetectionswitchingtheoperatingfrequencyofthe5.0GHz(802.11a/h)radiotoonethatisnotinterferingwiththeradarsystems.

Reference:

/en/US/docs/routers/access/wireless/software/guide/RadioChannelDFS.pdf

AlthoughDFShelpsreduceinterferencewithradarsystemsbut“DFSchannels”refertothe5GHzchannelsthatrequireDFScheck.Inotherwords,DFSchannelsarechannelsthatmayinterferewithradarsignal.ThereforeweshoulddisabletheseDFSchannels->AnswerCiscorrect.

UNII-2(5.250-5.350GHzand5.470-5.725GHz)whichcontainschannels52,56,60,64,100,104,108,112,116,120,124,128,132,136,and140arepermittedintheUnitedStates,butsharedwithradarsystems.Therefore,APsoperatingonUNII-2channelsarerequiredtouseDynamicFrequencySelection(DFS)toavoidinterferingwithradarsignals.IfanAPdetectsaradarsignal,itmustimmediatelystopusingthatchannelandrandomlypickanewchannel.

Reference:

/MR/WiFi_Basics_and_Best_Practices/Channel_Planning_Best_Practices

->ThereforeweshouldremoveUNII-2channelsfrom5GHzchannellist.

Question14

Whatisacharacteristicofpara-virtualization?

A.Para-virtualizationguestserversareunawareofoneanother

B.Para-virtualizationallowsdirectaccessbetweentheguestOSandthehypervisor

C.Para-virtualizationlackssupportforcontainers

D.Para-virtualizationallowsthehosthardwaretobedirectlyaccessed

Answer:

C

Explanation

Paravirtualizationworksdifferentlyfromthefullvirtualization.Itdoesn’tneedtosimulatethehardwareforthevirtualmachines.Thehypervisorisinstalledonaphysicalserver(host)andaguestOSisinstalledintotheenvironment.Virtualguestsawarethatithasbeenvirtualized,unlikethefullvirtualization(wheretheguestdoesn’tknowthatithasbeenvirtualized)totakeadvantageofthefunctions.

Infullvirtualization,guestswillissueahardwarecallsbutinparavirtualization,guestswilldirectlycommunicatewiththehost(hypervisor)usingdrivers.

Question15

DraganddropthecharacteristicsfromtheleftontotheQoScomponentstheydescribeontheright.

Answer:

+marking:appliedontraffictoconveyinformationtoadownstreamdevice

+shaping:processusedtobuffertrafficthatexceedsapredefinedrate

+classification:distinguishestraffictypes

+trust:permitstraffictopassthroughthedevicewhileretainingDSCP/COSvalue

Question16

Acustomerrequestsanetworkdesignthatsupportstheserequirements:

*FHRPredundancy

*multivendorrouterenvironment

*IPv4andIPv6hosts

Whichprotocoldoesthedesigninclude?

A.GLBP

B.VRRPversion2

C.VRRPversion3

D.HSRPversion2

Answer:

C

Explanation

UnlikeHSRPorGLBP,VRPPisanopenstandard.OnlyVRRPv3supportsbothIPv4andIPv6.

Question17

Refertotheexhibit.

vlan222

remote-span

!

vlan223

remote-span

!

monitorsession1sourceinterfaceFastEthernet0/1tx

monitorsession1sourceinterfaceFastEthernet0/2rx

monitorsession1sourceinterfaceport-channel5

monitorsession1destinationremotevlan222

WhathappenstoaccessinterfaceswhereVLAN222isassigned?

A.Theyareplacedintoaninactivestate

B.Adescription“RSPAN”isadded

C.STPBPDUguardisenabled

D.TheycannotprovidePoE

Answer:

A

Explanation

Accessports(includingvoiceVLANports)ontheRSPANVLANareputintheinactivestate.

Reference:

/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_55_se/configuration/guide/3750xscg/swspan.html

Question18

WhichsolutiondoIaaSserviceprovidersusetoextendaLayer2segmentacrossaLayer3network?

A.VXLAN

B.VTEP

C.VLAN

D.VRF

Answer:

A

Question19

WhatisacharacteristicofMACsec?

A.802.1AEprovidesencryptionandauthenticationservices

B.802.1AEisbuiltbetweenthehostandswitchusingtheMKAprotocol,whichnegotiatesencryptionkeysbasedonthemastersessionkeyfromasuccessful802.1Xsession

C.802.1AEisbuiltbetweenthehostandswitchusingtheMKAprotocolusingkeysgeneratedviatheDiffie-Hellmanalgorithm(anonymousencryptionmode)

D.802.1AEisnegotiatedusingCiscoAnyConnectNAMandtheSAPprotocol

Answer:

A

Explanation

MACsec,definedin802.1AE,providesMAC-layerencryptionoverwirednetwor