CCNA思科网络技术学院教程-第9章_TCP-IP传输层与应用层.ppt

1、第9章 TCP/IP传输层与应用层,主要内容,讨论传输层如何利用网络层提供的服务来提供源和目的地之间的端到端连接。,9.1 理解TCP/IP传输层,Transmission Control Protocol (TCP) User Datagram Protocol (UDP),Application,Transport,Internet,Network interface,Connection-OrientedConnectionless,1、TCP 数据段格式,Source port (16),Destination port (16),Sequence number (32),Header

2、length (4),Acknowledgement number (32),Reserved (6),Code bits (6),Window (16),Checksum (16),Urgent (16),Options (0 or 32 if any),Data (varies),20Bytes,Bit 0,Bit 15,Bit 16,Bit 31,No sequence or acknowledgment fields,2、UDP Segment Format,Source port (16),Destination port (16),Length (16),Data (if any)

3、,1,Bit 0,Bit 15,Bit 16,Bit 31,Checksum (16),8Bytes,3、Port Numbers,TCP,Port Numbers,FTP,TransportLayer,TELNET,DNS,SNMP,TFTP,SMTP,UDP,ApplicationLayer,21,23,25,53,69,161,RIP,520,理解 TCP 端口号,Source Port,Dest. Port,Host A,1028,23,SP,DP,Host Z,Telnet Z,Dest. port = 23.Send packet to my Telnet application.

4、,Determines destination upper-layer protocol,4、Protocol Field,TransportLayer,InternetLayer,TCP,UDP,ProtocolNumbers,IP,17,6,Send SYN (seq=100 ctl=SYN),SYN received,Host A,Host B,5、TCP Three Way Handshake/Open Connection,Send SYN (seq=100 ctl=SYN),SYN received,Send SYN, ACK (seq=300 ack=101 ctl=syn,ac

5、k),Host A,Host B,SYN received,TCP Three Way Handshake/Open Connection,Send SYN (seq=100 ctl=SYN),SYN received,Send SYN, ACK (seq=300 ack=101 ctl=syn,ack),Established (seq=101 ack=301 ctl=ack),Host A,Host B,SYN received,TCP Three Way Handshake/Open Connection,TCP Simple Acknowledgment,Window size = 1

6、,Sender,Receiver,TCP Simple Acknowledgment,Window size = 1,Sender,Receiver,Send 1,Receive 1,TCP Simple Acknowledgment,Window size = 1,Sender,Receiver,Send 1,Receive 1,Receive ACK 2,Send ACK 2,TCP Simple Acknowledgment,Window size = 1,Sender,Receiver,Send 1,Receive 1,Receive ACK 2,Send ACK 2,Send 2,R

7、eceive 2,TCP Simple Acknowledgment,Window size = 1,Sender,Receiver,Send 1,Receive 1,Receive ACK 2,Send ACK 2,Send 2,Receive 2,Receive ACK 3,Send ACK 3,TCP Simple Acknowledgment,Window size = 1,Sender,Receiver,Send 1,Receive 1,Receive ACK 2,Send ACK 2,Send 2,Receive 2,Receive ACK 3,Send ACK 3,Send 3,

8、Receive 3,Window size = 1,Sender,Receiver,Send 1,Receive 1,Receive ACK 2,Send ACK 2,Send 2,Receive 2,Receive ACK 3,Send ACK 3,Send 3,Receive 3,Receive ACK 4,Send ACK 4,TCP Simple Acknowledgment,TCP Sequence and Acknowledgment Numbers,Source Port,Dest. Port,Sequence #,Acknowledgement #,Source,Dest.,S

9、eq.,Ack.,1028,23,10,1,I just sent #10.,TCP Sequence and Acknowledgment Numbers,I just got #10, now I need #11.,Source Port,Dest. Port,Sequence #,Acknowledgement #,1028,23,Source,Dest.,10,Seq.,1,Ack.,1028,23,Source,Dest.,11,Seq.,1,Ack.,I just sent #10.,TCP Sequence and Acknowledgment Numbers,Source P

10、ort,Dest. Port,Sequence #,Acknowledgement #,1028,23,Source,Dest.,11,Seq.,2,Ack.,1028,23,Source,Dest.,10,Seq.,1,Ack.,1028,23,Source,Dest.,11,Seq.,1,Ack.,I just got #10, now I need #11.,I just sent #11.,TCP Sequence and Acknowledgment Numbers,Source Port,Dest. Port,Sequence #,Acknowledgement #,1028,23

11、,Source,Dest.,11,Seq.,2,Ack.,1028,23,Source,Dest.,10,Seq.,1,Ack.,1028,23,Source,Dest.,11,Seq.,1,Ack.,1028,23,Source,Dest.,12,Seq.,2,Ack.,I just got #11, now I need #12.,I just sent #11.,6、TCP Windowing,Sender,Receiver,TCP Windowing,Window size = 3 Send 2,Sender,Receiver,Window size = 3 Send 1,Window

12、 size = 3 Send 3,Window size = 3 Send 2,TCP Windowing,Sender,Window size = 3 Send 1,Window size = 3 Send 3,ACK 3 Window size = 2,Packet 3 isDropped,Receiver,Window size = 3 Send 2,TCP Windowing,Sender,Window size = 3 Send 1,Window size = 3 Send 3,ACK 3 Window size = 2,Packet 3 isDropped,Window size

13、= 3 Send 4,Window size = 3 Send 3,Receiver,Window size = 3 Send 2,TCP Windowing,Sender,Window size = 3 Send 1,Window size = 3 Send 3,ACK 3 Window size = 2,Packet 3 isDropped,Window size = 3 Send 4,Window size = 3 Send 3,ACK 5 Window size = 2,Receiver,9.2 应用层协议介绍,*Used by the router,Application,Transport,Internet,File Transfer - TFTP * - FTP * E-Mail - SMTP Remote Login - Telnet * -