第一章 概述new1

1、Communication Communication NetworkNetworkSwitchedSwitchedCommunication Communication NetworkNetworkBroadcastBroadcastCommunication Communication NetworkNetworkCircuit-SwitchedCircuit-SwitchedCommunication Communication NetworkNetworkPacket-SwitchedPacket-SwitchedCommunication Communication NetworkN

2、etworkDatagramDatagram Network NetworkVirtual Circuit NetworkVirtual Circuit Network的目的节点通过运行路由协议的特殊节点（交换机或者路由器）Communication Communication NetworkNetworkSwitchedSwitchedCommunication Communication NetworkNetworkBroadcastBroadcastCommunication Communication NetworkNetworkCircuit-SwitchedCircuit-Swit

3、chedCommunication Communication NetworkNetworkPacket-SwitchedPacket-SwitchedCommunication Communication NetworkNetworkDatagramDatagram Network NetworkVirtual Circuit NetworkVirtual Circuit NetworkDATA电路建立过程 数据传输 拆线 Host 1Host 2Node 1Node 2Host 1 和Node 1之间时延Host 2 和Node 1之间时延processing delay at Node

4、1incoming linksoutgoing linksNodeSWSW图2-1 路由共享假设：1) 2) =0.05erl210B12NsCommunication Communication NetworkNetworkSwitchedSwitchedCommunication Communication NetworkNetworkBroadcastBroadcastCommunication Communication NetworkNetworkCircuit-SwitchedCircuit-SwitchedCommunication Communication NetworkNe

5、tworkPacket-SwitchedPacket-SwitchedCommunication Communication NetworkNetworkDatagramDatagram Network NetworkVirtual Circuit NetworkVirtual Circuit Networkincoming linksoutgoing linksNodeMemorym/m/mModel 1Model 2Model 3图2-2 三种排队服务模式的比较分散网络/独立排队分散网络/集中排队综合网络/集中排队uu第三章排队论回答这个问题M/D/1(K)KLP图2-3 About Kn

6、ee Point缓冲区(K)第三章排队论回答这个问题Communication Communication NetworkNetworkSwitchedSwitchedCommunication Communication NetworkNetworkBroadcastBroadcastCommunication Communication NetworkNetworkCircuit-SwitchedCircuit-SwitchedCommunication Communication NetworkNetworkPacket-SwitchedPacket-SwitchedCommunicat

7、ion Communication NetworkNetworkDatagramDatagram Network NetworkVirtual Circuit NetworkVirtual Circuit NetworkHost AHost BHost EHost DHost CNode 1Node 2Node 3Node 4Node 5Node 6Node 7每一个分组独立交换每一个分组携带完整的目的地址不需要预约网络资源目前的IP网络Packet 1Packet 2Packet 3Packet 1Packet 2Packet 3Packet 1Packet 2Packet 3process

8、ing delay of Packet 1 at Node 2Host 1Host 2Node 1Node 2propagationdelay betweenHost 1 and Node 2 transmission time of Packet 1at Host 1Packet 1Packet 2Packet 3Packet 1Packet 2Packet 3Packet 1Packet 2Packet 3Host 1Host 2Node 1Node 2propagation delay between Host 1 and Node 1VCestablishmentVCterminati

9、onDatatransferHost AHost BHost EHost DHost CNode 1Node 2Node 3Node 4Node 5Node 6Node 7Q: 举一个生活中的例子：预约资源（电路交换）和按需分配（分组交换）?层功能的方法Telnet FTPNFSPacketradioCoaxial cableFiberoptic应用应用传输介质传输介质HTTPTelnet FTPNFSPacketradioCoaxial cableFiberoptic应用应用传输介质传输介质HTTP中间层中间层ApplicationPresentationSessionTransportNe

10、tworkDatalinkPhysicalApplicationPresentationSessionTransportNetworkDatalinkPhysicalNetworkDatalinkPhysicalPhysical mediumdatadatadatadatadatadatadatadatadatadatadatadatadatadataControl (MAC) (e.g., CSMA/CD)H1H2R1R2R3R4R5R6H2 R4H2 R6Fwd tableFwd tableApplicationPresentationSessionTransportNetworkData

11、linkPhysicalInternetHost-to-networkTransportApplicationIPLANPacketradioTCPUDPTelnetFTPDNSmessagesegmentdatagramframesourceapplicationtransportnetworklinkphysicalHtHnHlMHtHnMHtMMdestinationapplicationtransportnetworklinkphysicalHtHnHlMHtHnMHtMMnetworklinkphysicallinkphysicalHtHnHlMHtHnMHtHnHlMHtHnMHtHnHlMHtHnHlMrouterswitch电话呼叫间隔；电话持续时间电话还要持续的时间分布与它已经持续了时间无关又是一个全