思科网络技术学院教程(第二章 高层协议)

Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3高层协议第二章应用层与会话层Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.33Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3事务应用字处理图表电子表格数据库设计/制造课题计划其他应用层•选择网络应用支持用户的事务应用网络应用电子邮件文件传输远程访问客户端/服务器模式处理信息定位网络管理其他4Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3?Graphics?VisualImagesPICTTIFFJPEGGIF表示层•为应用层提供代码格式的转换?Text?DataASCIIEBCDICEncrypted?Sound?VideoMIDIMPEGQuickTimelogin:5Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3网络文件系统(NFS)结构化查询语言(SQL)远程过程调用(RPC)X窗口系统互连网浏览器DNA会话控制协议(SCP)会话层ServiceRequestServiceReply•支持在不同主机上对等应用程序之间的对话传输层Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.37Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3传输层概览•将会话层数据分割成较小的分组•建立端到端的连接•将分组从一端主机发送到另一端主机•保证数据可靠传输8Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3面向连接的会话同步同步确认连接协商数据传输(发送分组)SenderReceiver连接建立9Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3流量控制BufferFullTransmitSenderReceiver10Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3流量控制BufferFullTransmitNotReadyStopSenderReceiver11Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3流量控制BufferFullProcessSegmentsBufferOKTransmitNotReadyStopSenderReceiver12Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3流量控制BufferFullProcessSegmentsBufferOKTransmitNotReadyStopReadyGoSenderReceiver13Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3流量控制BufferFullProcessSegmentsBufferOKTransmitNotReadyStopReadyGoResumeTransmissionSenderReceiver14Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3窗口技术Windowsize=1Send1Receive1SenderReceiver15Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3窗口技术Windowsize=1Send1Receive1Ack2SenderReceiver16Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3窗口技术Windowsize=1Send1Receive1Ack2Send2Receive2SenderReceiver17Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3窗口技术Windowsize=1Send1Receive1Ack2Send2Receive2Ack3SenderReceiver18Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3窗口技术Windowsize=1Send1Receive1Ack2Send2Receive2Ack3Send1Send2Receive1Receive2Windowsize=3Send3Receive3SenderReceiverSenderReceiver19Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3窗口技术Windowsize=1Send1Receive1Ack2Send2Receive2Ack3Send1Send2Receive1Receive2Windowsize=3Send3Receive3Ack4SenderReceiverSenderReceiver20Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3窗口技术Windowsize=1Send1Receive1Ack2Send2Receive2Ack3Send1Send2Receive1Receive2Windowsize=3Send3Receive3Ack4Send4SenderReceiverSenderReceiver21Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3正向确认SenderReceiver12345622Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3正向确认SenderReceiverSend2Send1Send312345612323Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3正向确认SenderReceiverSend2Send1Send3Ack4Send412345612324Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3正向确认SenderReceiverSend2Send1Send3Ack4Send5Send4Send61234561234625Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3正向确认SenderReceiverSend2Send1Send3Ack4Send5Send4Send6Ack51234561234626Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3正向确认SenderReceiverSend2Send1Send3Ack4Send5Send4Send6Ack5Send512345612345627Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3正向确认SenderReceiverSend2Send1Send3Ack4Send5Send4Send6Ack5Send5Ack712345612345628Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3正向确认SenderReceiverSend2Send1Send3Ack4Send5Send4Send6Ack5Send5Ack712345612345629Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3分组如何穿过通信网络？RoutedpacketsEnd-to-endsegments