CCNA思科认证网络工程师【CCNA 9-1】WAN介绍.ppt

*PPP的阶段验证，bothPurpose:Thispageshowsanexampleofdebugpppauthenticationoutput.TheoutputillustratesasuccessfulCHAPauthenticationchallenge.Emphasize:Thedebugpppauthenticationcommanddisplaystheauthenticationexchangesequenceasitoccurs.*Purpose:Thisfigureprovidesabig-picturedefinitionofFrameRelay. Emphasize:FrameRelayisusedbetweentheCPEdeviceandtheFrameRelayswitch.ItdoesNOTaffecthowpacketsgetroutedwithintheFrameRelaycloud.FrameRelayisapurelyLayer2protocol.ThenetworkprovidingtheFrameRelayservicecanbeeitheracarrier-providedpublicnetworkoranetworkofprivatelyownedequipmentservingasingleenterprise.MakeacleardistinctionbetweenDCE,DTE,andCPE.EmphasizethatFrameRelayoverSVCsisnotdiscussedinthischapterbecauseitisnotwidelysupportedbyserviceprovidersatthistime.TheserviceprovidermustalsosupportSVCsinorderforFrameRelayoverSVCstooperate. Note:InCiscoIOSRelease11.2,twotrafficshapingfeatureswereintroduced:Generic(adaptive)trafficshapingFrameRelaytrafficshapingBothofthesefeaturescanbeusedtoadjusttherateatwhichtrafficissentbytherouter.Inaddition,thesefeaturesallowtheroutertothrottlethetrafficratebasedonBECNsreceivedfromtheFrameRelayswitch.Neitherofthesefeaturesarediscussedinthiscourse.FrameRelaytrafficshapingisdiscussedintheBuildingCiscoRemoteAccessNetworks(BCRAN)course.InformationonbothcanbefoundinCiscodocumentation. *Purpose:ThisfigureprovidesanoverviewofterminologysothatthestudentispreparedtounderstandtheFrameRelayoperationdiscussion. TheterminologyusedwithFrameRelayvariesbyserviceprovider.Thesearethecommonlyusedterms.PointoutthelocalaccessloopandnotethatthelocalaccessrateisdifferentthantherateusedwithintheFrameRelaycloud.TheDLCIisoflocalsignificance,therefore,pointoutt