思科网络学院CCNA4练习题和答案EnglishFormDEWANv4.docx

思科网络学院CCNA4练习题和答案EnglishFormDEWANv4.docx

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思科网络学院CCNA4练习题和答案EnglishFormDEWANv4

思科网络学院CCNA4练习题和答案EnglishFormDEWANChapter1

.WANSwitchingConcepts

AssessmentItem:

Whatisanadvantageofpacket-switchedtechnologyovercircuit-switchedtechnology?

Packet-switchednetworksarelesssusceptibletojitterthancircuit-switchednetworksare.

Packet-switchednetworkscanefficientlyusemultipleroutesinsideaserviceprovidernetwork.

Packet-switchednetworksdonotrequireanexpensivepermanentconnectiontoeachendpoint.

Packet-switchednetworksusuallyexperiencelowerlatencythancircuit-switchednetworksexperience.

ResetViewLearnerResponse

ScoringRulefor:

correctnessofresponse

2pointsforOption2

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.2.3WANDataLinkLayerConcepts

AssessmentItem:

WhichstatementaboutWANprotocolsiscorrect?

ATMdiffersfromotherWANprotocolsinthatitusesvariablysizedpackets.

MostWANprotocolsuseHDLCoravariantofHDLCasaframingmechanism.

Theframeheaderconsistsoftheframechecksequenceandcyclicredundancycheck.

ISDNdiffersfromFrameRelay,HDLC,andATMinthatitispacket-switchedratherthancircuit-switchedtechnology.

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption2

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.2.4WANSwitchingConcepts

AssessmentItem:

Whyisthecallsetuptimeofacircuit-switchedWANimplementationconsideredadrawback?

Routingprotocolsareincompatiblewiththisfunction.

Itrestrictsthecommunicationsenttovoicetrafficonly.

Atelephonemustbeusedtoinitiallystarttransferringdata.

Datacannotbetransferreduntilacircuithasbeenestablished.

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption4

AssessmentItem:

WhichstatementistrueaboutthedifferencesbetweenaWANandaLAN?

WANsgenerallysupporthigherbandwidththanLANssupport.

AWANlinktypicallytraversesshortergeographicdistancesthanaLANlinktraverses.

AWANoftenreliesontheservicesofcarriers,suchastelephoneorcablecompanies,butaLANdoesnot.

AllWANimplementationsgenerallyusethesameLayer2protocolbuttherearemanyacceptedLANLayer2protocolsinuse.

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption3

1.2.2WANPhysicalLayerConcepts

AssessmentItem:

Whichstatementistrueaboutdataconnectivitybetweenacustomerandaserviceprovider?

NormallytheCSU/DSUisthedesignateddemarcationpointfortheserviceproviderbutnotthecustomer.

Thesegmentbetweenthedemarcationpointandthecentralofficeisknownasthe"lastmile."

ThelocalloopisthesegmentbetweentheCSU/DSUandtheserialportonarouter.

PuttingdataonthelocalloopistheresponsibilityoftheDTE.

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption2

1.1.3TheEvolvingNetworkModel

AssessmentItem:

Whichstatementistrueofthefunctionalityofthelayersinthehierarchicalnetworkmodel?

Thepurposeoftheaccesslayeristoprovideveryhighbandwidthcommunicationsbetweennetworkdevices.

Mostsecurityscreeningtopreventunauthorizedentrytothenetworkhappensatthecorelayer.

Untrustedexternalconnectionsaresegmentedfromtherestofthenetworkatallthreelevels.

ThedistributionlayeraggregatesWANconnectionsattheedgeofthecampus.

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption4

1.2.2WANPhysicalLayerConcepts

AssessmentItem:

Whichtwodevicesarecommonlyusedasdatacommunicationsequipment?

（Choosetwo.）

modem

router

CSU/DSU

ISDNswitch

Ethernetswitch

Reset

ScoringRulefor:

correctnessofresponse

Option1andOption3arecorrect.

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.3.4PacketSwtichedConnectionOptions

AssessmentItem:

AcompanyneedsaWANconnectionthatiscapableoftransferringvoice,video,anddataataminimumdatarateof155Mbps.WhichWANconnectionisthebestchoice?

DSL

ATM

ISDNBRI

ISDNPRI

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption3

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.2.4WANSwitchingConcepts

AssessmentItem:

Whichswitchingtypewillallowthecommunicationdevicesintheprovidernetworktobesharedandonlyallocatedtoanindividualsubscriberduringdatatransfer?

circuit-switched

dedicatedswitchedlines

frame-switched

packet-switched

ResetViewLearnerResponse

ScoringRulefor:

correctnessofresponse

2pointsforOption4

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.2.2WANPhysicalLayerConcepts

AssessmentItem:

Whichtermdescribesadevicethatwillputdataonthelocalloop?

DLCI

DTE

DCE

BRI

PRI

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption3

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.2.2WANPhysicalLayerConcepts

AssessmentItem:

Fordigitallines,whichdeviceisusedtoestablishthecommunicationslinkbetweenthecustomerequipmentandthelocalloop?

CSU/DSU

FrameRelayswitch

ISDNswitch

modem

PBXswitch

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption1

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.3.3CircuitSwitchedConnectionOptions

AssessmentItem:

AU.S.companyrequiresaWANconnectionusedonlytotransfersalesdatafromindividualstorestothehomeoffice.Alltransferswilloccurafterbusinesshours.Therequiredbandwidthforthisconnectionisestimatedtobelessthan38kbps.Whichtypeofconnectionrequirestheleastinvestmentforthiscompany?

ATM

ISDN

analogdialup

T1LeasedLine

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption3

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.3.5InternetConnectionOptions

AssessmentItem:

WhattypeofconnectivityisestablishedwhenVPNsareusedfromtheremotesitetotheprivatenetwork?

PVCs

DLCIs

tunnels

virtualcircuits

dedicatedLayer2links

ResetViewLearnerResponse

ScoringRulefor:

correctnessofresponse

2pointsforOption3

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.3.5InternetConnectionOptions

AssessmentItem:

Whatcancauseareductioninavailablebandwidthonacablebroadbandconnection?

smallercells

numberofsubscribers

committedinformationrate

distancefromthecentralofficeoftheprovider

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption2

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.3.3CircuitSwitchedConnectionOptions

AssessmentItem:

WhatthreetermsareassociatedwithISDNPRI?

（Choosethree.）

DLCI

circuitswitching

packetswitching

databearerchannels

switchedvirtualcircuits

time-divisionmultiplexing

Reset

ScoringRulefor:

correctnessofresponse

Option2,Option4,andOption6arecorrect.

1pointforeachcorrectoption

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.3.3CircuitSwitchedConnectionOptions

AssessmentItem:

WhataretwoadvantagesofananalogPSTNWANconnection?

（Choosetwo.）

lowcost

availability

trafficencryption

availablebandwidth

supportforvoiceandvideo

Reset

ScoringRulefor:

correctnessofresponse

Option1andOption2arecorrect

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.3.4PacketSwtichedConnectionOptions

AssessmentItem:

WhichWANtechnologyusesafixedpayloadof48bytesandistransportedacrossbothswitchedandpermanentvirtualcircuits?

ATM

ISDN

FrameRelay

metroEthernet

ResetViewLearnerResponse

ScoringRulefor:

correctnessofresponse

2pointsforOption1

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.3.4PacketSwtichedConnectionOptions

AssessmentItem:

WhichthreefeaturesareidentifiedwithFrameRelayconnections?

（Choosethree.）

CIR

DLCI

DSLAM

PVC

SPID

53-bytecells

Reset

ScoringRulefor:

correctnessofresponse

Option1,Option2,andOption4arecorrect

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.3.5InternetConnectionOptions

AssessmentItem:

Whichpacket-switchedWANtechnologyoffershigh-bandwidthconnectivitycapableofmanagingdata,voice,andvideoallonthesameinfrastructure?

TimeDivisionMultiplexing（TDM）

metroEthernet

IntegratedServicesDigitalNetwork（ISDN）

PublicSwitchedTelephoneNetwork（PSTN）

ResetViewLearnerResponse

ScoringRulefor:

correctnessofresponse

2pointsforOption2

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.2.2WANPhysicalLayerConcepts

AssessmentItem:

Whichnetworkingdeviceistypicallyusedtoconcentratethedial-inanddial-outtrafficofmultipleuserstoandfromanetwork?

corerouter

accessserver

FrameRelayswitch

ATMswitch

Reset

ScoringRulefor:

correctnessofresponse

2pointsforOption2

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.2.1WANTechnologyOverview

AssessmentItem:

WhichthreeWANdevicescanbefoundinthecloud?

（Choosethree.）

ATMswitches

corerouters

CSU/DSU

Ethernetswitches

FrameRelayswitches

repeaters

Reset

ScoringRulefor:

correctnessofresponse

Option1,Option2,andOption5arecorrect.

1pointforeachcorrectoption.

Thisitemreferencescontentfromthefollowingareas:

CCNAExploration

1.2.1WANTechnologyOverview

AssessmentItem:

AtwhichtwolayersoftheOSImodeldoesaWANoperate?

（Choosetwo.）

PhysicalLayer

DataLinkLayer