二零二三年 优质公开课TransportLayerProtocols.pptx

《HCNA-HNTD Fast Training》Transport Layer Protocols课程团队：叶礼兵 王苏南 张悦 吴伟强 Foreword The transport layer is associated with the end-to-end behavior of transport layer protocols, that are defined once data reaches the intended destination. TCP and UDP represent the protocols commonly supported within IP networks. The characteristics of data, such as sensitivity to delay and the need for reliability often determines the protocols used at the transport layer. This section focuses on the knowledge of how such characteristics are supported through the behavior of each protocol.Page 2 Objectives Upon completion of this section, trainees will be able to:Describe the common differences between TCP and UDP.Describe the forms of data to which TCP and UDP are applied.Identify well known TCP and UDP based port numbers.Page 3 Transmission Control ProtocolPage 4Host AHost BRequestReplyTCP ConnectionA connection is established before data is sent. TCP PortsPage 5ProtocolPortFTP20 - 21HTTP80TELNET23SMTP25Host AHTTP ServerDataS:1027D:80DataS:80D:1027Ports represent individual services such as those listed above. TCP HeaderPage 620bytesTCP HeaderDataIP0 15 31Destination PortSequence NumberWindowChecksumOptionsSource PortAcknowledge NumberHeader LengthResv.URGRSTACKPSHSYNFINUrgent PointerPaddingECECWRNS TCP Connection EstablishmentPage 7?Send SYN?Send SYN,ACK?Send ACKHost AServer A(seq=a,CTL=SYN)(seq=b,ack=a+1,CTL=SYN,ACK)(seq=a+1,ack=b+1,CTL=ACK)A TCP connection is established after a three-way handshake. Page 8 TCP Transmission ProcessPage 9Send 1,2,3Acknowledge 4Send 4,5,6Acknowledge 4Send 4,5,6Host AServer A TCP Flow ControlPage 10ack 2049 window 2048ack 4097 window 2048length 1024 window 4096Host AServer Alength 1024 window 4096length 1024 window 4096length 1024 window 4096length 1024 window 4096length 1024 window 4096 TCP Connection TerminationPage 11? FIN? ACK?