数据与计算机通信 10

《数据与计算机通信 10》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、PublicInfrastructureBuildingsComputersPeopleSmartCardsHomesAppliancesTransportationVehiclesVendingMachines$...数据通信与网络1DataandComputerCommunications电路交换与分组交换10CircuitSwitchingandPacketSwitching交换式通信网电路交换网电路交换的概念控制信令软交换体系结构分组交换原理X.25帧中继PartIIIWANOVERVIEWSwitchingNetwork

2、s交换式通信网CircuitSwitching电路交换网CircuitSwitchingConcepts电路交换的概念ControlSignaling控制信令难点！SoftswitchArchitecture软交换体系结构PacketSwitchingPrinciples分组交换原理X.25(Optional)FrameRelay帧中继(Optional)310.1SwitchingNetworksLongdistancetransmissionistypicallydoneoveranetworkofswitchednodesNod

3、esnotconcernedwithcontentofdataEnddevicesarestationsComputer,terminal,phone,etc.AcollectionofnodesandconnectionsisacommunicationsnetworkDataroutedbybeingswitchedfromnodetonode4NodesNodesmayconnecttoothernodesonly,ortostationsandothernodes仅与其他节点相连5-7Nodetonodelinksusuall

4、ymultiplexedNetworkisusuallypartiallyconnectedSomeredundantconnectionsaredesirableforreliabilityTwodifferentswitchingtechnologiesCircuitswitchingPacketswitching5SimpleSwitchedNetwork6OVERVIEWSwitchingNetworks交换式通信网CircuitSwitching电路交换网CircuitSwitchingConcepts电路交换的概念Cont

5、rolSignaling控制信令难点！SoftswitchArchitecture软交换体系结构PacketSwitchingPrinciples分组交换原理X.25(Optional)FrameRelay帧中继(Optional)710.2CircuitSwitchingDedicatedcommunicationpathbetweentwostationsThreephasesEstablishTransferDisconnectMusthaveswitchingcapacityandchannelcapacitytoestabl

6、ishconnectionMusthaveintelligencetoworkoutrouting8CircuitSwitching-ApplicationsInefficientChannelcapacitydedicatedfordurationofconnection连接期间信道的容量是专用的Ifnodata,capacitywastedSetup(connection)takestimeOnceconnected,transferistransparentDevelopedforvoicetraffic(phone)9Publ

7、icCircuitSwitchedNetwork10TelecommsComponentsSubscriberDevicesattachedtonetworkSubscriberline用户线路LocalLoopSubscriberloopConnectiontonetworkFewkmuptofewtensofkmExchange交换局SwitchingcentersEndoffice-supportssubscribersTrunks中继线BranchesbetweenexchangesMultiplexed11CircuitEs

8、tablishment12OVERVIEWSwitchingNetworks交换式通信网CircuitSwitching电路交换网CircuitSwitchingConcepts电路交换的概念ControlSignali