第四章思科高级网络互联英文版答案文档格式.docx

第四章思科高级网络互联英文版答案文档格式.docx

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HSRP

PortFast

trunking

EtherChannel

Explanation:

PortFastisusedtoreducetheamountoftimethataportspendsgoingthroughthespanning-treealgorithm,sothatdevicescanstartsendingdatasooner.TrunkingcanbeimplementedinconjunctionwithEtherChannel,buttrunkingalonedoesnotaggregateswitchlinks.HSRPisusedtoload-balancetrafficacrosstwodifferentconnectionstoLayer3devicesfordefaultgatewayredundancy.HSRPdoesnotaggregatelinksateitherLayer2orLayer3asEtherChanneldoes.

2.WhichstatementistrueregardingtheuseofPAgPtocreateEtherChannels?

Itrequiresfullduplex.

ItisCiscoproprietary.

ItrequiresmorephysicallinksthanLACPdoes.

Itincreasesthenumberofportsthatareparticipatinginspanningtree.

Itmandatesthatanevennumberofports（2,4,6,etc.）beusedforaggregation.

PAgPisusedtoautomaticallyaggregatemultipleportsintoanEtherChannelbundle,butitonlyworksbetweenCiscodevices.LACPcanbeusedforthesamepurposebetweenCiscoandnon-Ciscodevices.PAgPmusthavethesameduplexmodeatbothendsandcanusetwoportsormore.Thenumberofportsdependsontheswitchplatformormodule.AnEtherChannelaggregatedlinkisseenasoneportbythespanning-treealgorithm.

3.WhichtwoprotocolsareusedtoimplementEtherChannel?

（Choosetwo.）

SpanningTreeProtocol

RapidSpanningTreeProtocol

PortAggregationProtocol

LinkAggregationControlProtocol

CiscoDiscoveryProtocol

PortAggregationProtocolandLinkAggregationControlProtocolareusedtoimplementEtherChannel.SpanningTreeandRapidSpanningTreeProtocolareusedtopreventswitchingloops.CiscoDiscoveryProtocolisCisco-proprietaryandisusedtodiscoveryinformationaboutadjacentCiscodevicessuchasmodelnumberandIPaddress.

4.WhichstatementdescribesacharacteristicofEtherChannel?

Itcancombineuptoamaximumof4physicallinks.

Itcanbundlemixedtypesof100Mb/sand1Gb/sEthernetlinks.

Itconsistsofmultipleparallellinksbetweenaswitchandarouter.

Itismadebycombiningmultiplephysicallinksthatareseenasonelinkbetweentwoswitches.

AnEtherChannelisformedbycombiningmultiple（sametype）Ethernetphysicallinkssotheyareseenandconfiguredasonelogicallink.Itprovidesanaggregatedlinkbetweentwoswitches.CurrentlyeachEtherChannelcanconsistofuptoeightcompatiblyconfiguredEthernetports.

5.WhichstatementdescribesanEtherChannelimplementation?

EtherChanneloperatesonlyatLayer2.

PAgPcannotbeusedinconjunctionwithEtherChannel.

AtrunkedportcanbepartofanEtherChannelbundle.

EtherChannelcansupportuptoamaximumoftenseparatelinks.

Upto16linkscanbegroupedinanEtherChannelbyusingthethePAgPorLACPprotocol.EtherChannelcanbeconfiguredasaLayer2bundleoraLayer3bundle.ConfiguringaLayer3bundleisbeyondthescopeofthiscourse.IfatrunkedportisapartoftheEtherChannelbundle,allportsinthebundleneedtobetrunkportsandthenativeVLANmustbethesameonalloftheseports.Abestpracticeistoapplytheconfigurationtotheportchannelinterface.Theconfigurationisthenautomaticallyappliedtotheindividualports.

6.AnEtherChannellinkusingLACPwasformedbetweentwoswitches,S1andS2.Whileverifyingtheconfiguration,whichmodecombinationcouldbeutilizedonbothswitches?

​

S1-onandS2-passive

S1-passiveandS2-passive​

S1-onandS2-active​

S1-passiveandS2-active

AnEtherChannellinkwillbeformedusingLACPwhenbothswitchesareinonmodeorinactivemode,orwhenoneofthemisinpassivemodeandtheotherisinactivemode.

7.WhatisanadvantageofusingLACP?

increasesredundancytoLayer3devices

decreasesthechanceofaspanning-treeloop

allowsautomaticformationofEtherChannellinks

providesasimulatedenvironmentfortestinglinkaggregation

decreasestheamountofconfigurationthatisneededonaswitchforEtherChannel

8.WhatisabestpracticetousebeforebeginninganEtherChannelimplementation?

AssignaffectedinterfacestoVLAN1.

AssignaffectedinterfacestothemanagementVLAN.

Shutdowneachoftheaffectedinterfaces.

Enableeachoftheaffectedinterfaces.

AssignaffectedinterfacestoanunusedVLAN.

BeforeconfiguringEtherChannel,theinterfacesusedshouldbeshutdownsothatanyincompleteconfigurationwillnotcauseactivityonthelink.

9.WhichPA