TCP-IP协议栈.ppt

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1、 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-1 2004,Cisco Systems,Inc.All rights reserved.2004,Cisco Systems,Inc.All rights reserved.2TCP/IP 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-3本章目标本章目标1.了解了解TCP/IP通信协议通信协议2.掌握掌握TCP、UDP及及IP报文格式报文格式3.理解并掌握理解并掌握TCP、UDP、IP通信原理通信原理4.熟悉熟悉PING、TR

2、ACEROUTE、ARP、RARP等几种三层协议等几种三层协议 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-4早期的协议栈早期的协议栈普遍性的普遍性的介绍介绍介绍介绍 TCP/IPTCP/IP主机主机InternetTCP/IP主机主机 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-5TCP/IP TCP/IP 协议栈协议栈协议栈协议栈764325432应用层应用层表示层表示层会话层会话层传输层传输层网络层网络层数据链路层数据链路层物理层物理层1应用层应用层传输层传输层互联

3、网层互联网层数据链路层数据链路层物理层物理层1 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-6应用层概述应用层概述应用层概述应用层概述*Used by the router应用层应用层传输层传输层互联网层互联网层数据链路层数据链路层物理层物理层File Transfer-TFTP*-FTP*-NFSE-Mail-SMTPRemote Login-Telnet*-rlogin*Network Management-SNMP*Name Management-DNS*2004,Cisco Systems,Inc.All rights re

4、served.ICND 2.00-7传输层概述传输层概述传输层概述传输层概述Transmission ControlProtocol(TCP)User Datagram Protocol(UDP)应用层应用层传输层传输层互联网层互联网层数据链路层数据链路层物理层物理层面向连接的面向连接的非面向连接的非面向连接的 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-8TCP TCP 报文格式报文格式报文格式报文格式Source port(16)Destination port(16)Sequence number(32)Headerlengt

5、h(4)Acknowledgement number(32)Reserved(6)Code bits(6)Window(16)Checksum(16)Urgent(16)Options(0 or 32 if any)Data(varies)20BytesBit 0Bit 15Bit 16Bit 31 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-9端口号端口号端口号端口号TCP端口号端口号FTP传输层传输层TELNETDNSSNMPTFTPSMTPUDP应用层应用层2123255369161RIP520 2004,Cisco Syst

6、ems,Inc.All rights reserved.ICND 2.00-10TCP TCP 端口号端口号端口号端口号SourcePortDest.PortHost A102823SPDPHost ZTelnet ZDest.port=23.Send packet to my Telnet application.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-11Send SYN(seq=100 ctl=SYN)SYN receivedHost AHost B1TCP TCP 三次握手建立连接三次握手建立连接三次握手建立连接三次握手

7、建立连接 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-12Send SYN(seq=100 ctl=SYN)SYN receivedSend SYN,ACK(seq=300 ack=101 ctl=syn,ack)Host AHost BSYN received12TCP TCP 三次握手建立连接三次握手建立连接三次握手建立连接三次握手建立连接 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-13Send SYN(seq=100 ctl=SYN)SYN receivedSen

8、d SYN,ACK(seq=300 ack=101 ctl=syn,ack)Established(seq=101 ack=301 ctl=ack)Host AHost B123SYN receivedTCP TCP 三次握手建立连接三次握手建立连接三次握手建立连接三次握手建立连接 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-14TCPTCP简单确认简单确认简单确认简单确认Window size=1 Sender Receiver 2004,Cisco Systems,Inc.All rights reserved.ICND 2.0

9、0-15TCPTCP简单确认简单确认简单确认简单确认Window size=1 Sender ReceiverSend 1Receive 1 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-16TCPTCP简单确认简单确认简单确认简单确认Window size=1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-17TCPTCP简单确认简单确认简单确认简单确认Window

10、 size=1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2Send 2Receive 2 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-18TCPTCP简单确认简单确认简单确认简单确认Window size=1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2Send 2Receive 2Receive ACK 3Send ACK 3 2004,Cisco Systems,Inc.All rights rese

11、rved.ICND 2.00-19TCPTCP简单确认简单确认简单确认简单确认Window size=1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2Send 2Receive 2Receive ACK 3Send ACK 3Send 3Receive 3 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-20Window size=1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2Send 2Receive 2R

12、eceive ACK 3Send ACK 3Send 3Receive 3Receive ACK 4Send ACK 4TCPTCP简单确认简单确认简单确认简单确认 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-21TCP TCP 序列号和确认号序列号和确认号序列号和确认号序列号和确认号SourcePortDest.PortSequence#Acknowledgement#Source Dest.Seq.Ack.102823101I justsent#10.2004,Cisco Systems,Inc.All rights reser

13、ved.ICND 2.00-22TCP 序列号和确认号序列号和确认号I just got#10,now I need#11.SourcePortDest.PortSequence#Acknowledgement#102823Source Dest.1010Seq.1Ack.102823Source Dest.1111Seq.1Ack.I justsent#10.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-23TCPTCP序列号和确认号序列号和确认号序列号和确认号序列号和确认号SourcePortDest.PortSequence#A

14、cknowledgement#102823Source Dest.1111Seq.2Ack.102823Source Dest.1010Seq.1Ack.102823Source Dest.1111Seq.1Ack.I just got#10,now I need#11.I justsent#11.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-24TCPTCP序列号和确认号序列号和确认号序列号和确认号序列号和确认号SourcePortDest.PortSequence#Acknowledgement#102823Source Dest

15、.1111Seq.2Ack.102823Source Dest.1010Seq.1Ack.102823Source Dest.1111Seq.1Ack.102823Source Dest.1212Seq.2Ack.I just got#11,now I need#12.I justsent#11.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-25TCPTCP窗口窗口窗口窗口SenderReceiver 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-26TCPTCP窗口窗口窗口

16、窗口Window size=3Send 2SenderReceiverWindow size=3Send 1Window size=3Send 3 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-27Window size=3Send 2TCPTCP窗口窗口窗口窗口SenderWindow size=3Send 1Window size=3Send 3ACK 3Window size=2Packet 3 isDroppedReceiver 2004,Cisco Systems,Inc.All rights reserved.ICND 2

17、.00-28Window size=3Send 2TCPTCP窗口窗口窗口窗口SenderWindow size=3Send 1Window size=3Send 3ACK 3Window size=2Packet 3 isDroppedWindow size=2Send 4Window size=2Send 3Receiver 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-29Window size=3Send 2TCPTCP窗口窗口窗口窗口SenderWindow size=3Send 1Window size=3Send 3AC

18、K 3Window size=2Packet 3 isDroppedWindow size=2Send 4Window size=2Send 3ACK 5Window size=2Receiver 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-30没有序列号或没有序列号或 确认号字段确认号字段UDP UDP 报文格式报文格式报文格式报文格式Source port(16)Destination port(16)Length(16)Data(if any)1Bit 0Bit 15Bit 16Bit 31Checksum(16)8Bytes

19、 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-31互联网层概述互联网层概述互联网层概述互联网层概述OSI 网络层在网络层在TCP/IP里被描述成互联网层里被描述成互联网层Internet Protocol(IP)Internet Control MessageProtocol(ICMP)Address ResolutionProtocol(ARP)Reverse AddressResolution Protocol(RARP)应用层应用层传输层传输层互联网层互联网层数据链路层数据链路层物理层物理层 2004,Cisco System

20、s,Inc.All rights reserved.ICND 2.00-32IP IP 数据包数据包数据包数据包Version(4)Destination IP Address(32)Options(0 or 32 if any)Data(varies if any)1Bit 0Bit 15Bit 16Bit 31HeaderLength(4)Priority&Type of Service(8)Total Length(16)Identification(16)Flags(3)Fragment offset(13)Time to live(8)Protocol(8)Header checks

21、um(16)Source IP Address(32)20Bytes 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-33决定目的高层协议决定目的高层协议 协议字段协议字段协议字段协议字段传输层传输层互连网层互连网层TCPUDP协议号协议号IP176 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-34因特网控制报文协议因特网控制报文协议因特网控制报文协议因特网控制报文协议ApplicationTransportInternetData LinkPhysicalDestinati

22、on UnreachableEcho(Ping)OtherICMP1 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-35Internet Control Message Protocol1、目的不可达、目的不可达ICMP报文（目的网络、目的主机、目的报文（目的网络、目的主机、目的协议、目的端口不可达）协议、目的端口不可达）2、超时、超时ICMP报文（报文（TTL每经过一次路由器就减每经过一次路由器就减1，减，减到到0时，数据包被丢弃。时，数据包被丢弃。Trace充分利用了充分利用了ICMP超时报超时报文）文）3、重定向、重定向ICMP

23、报文（向源主机通知更好的路由）报文（向源主机通知更好的路由）4、ICMP回应请求与回应应答（回应请求与回应应答（ping发送和接收发送和接收icmp echo/icmp echo reply报文）报文）2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-36Ping命令的结论命令的结论PingPing的主要功能是确定一个给定的的主要功能是确定一个给定的IPIP地址是否可以到达。地址是否可以到达。如果如果pingping执行成功，则暗示：执行成功，则暗示：1 1）从源到目的节点从源到目的节点存在一条可以工作的路径；存在一条可以工作的路径；2

24、2）目标）目标IPIP地址对应的机器在正常工作；地址对应的机器在正常工作；3 3）从目标节点到源节点从目标节点到源节点存在一条可以工作的路径。存在一条可以工作的路径。但是，从源到目标的路径与从目标回源节点的路径可能不但是，从源到目标的路径与从目标回源节点的路径可能不一致。即不对称路由。一致。即不对称路由。2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-37Ping命令的输出结果命令的输出结果!PingPing操作成功，收到了操作成功，收到了icmpicmp echo reply echo reply报文报文.未收到任何报文未收到任何报文

25、U U icmpicmp不可到达目的主机不可到达目的主机N N icmpicmp不可到达目的网络不可到达目的网络P P icmpicmp不可到达目的端口不可到达目的端口Q Q icmpicmp源地址失踪源地址失踪M M icmpicmp禁止数据包分段禁止数据包分段?收到无法识别的数据包收到无法识别的数据包 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-38Traceroute命令的原理命令的原理TracerouteTraceroute命令描述了命令描述了从源到目的地址的详细路径从源到目的地址的详细路径，即整个路径，即整个路径上的所有路

26、由器。其原理如下：上的所有路由器。其原理如下：1 1）最开始，源向目的地址发送）最开始，源向目的地址发送3 3个个TTLTTL1 1的数据包，第的数据包，第1 1个路由器个路由器收到该包后将其收到该包后将其TTLTTL改为改为0 0，并向源发送一个，并向源发送一个ICMPICMP超时消息，源在超时消息，源在接到这个消息后便知道了到达目的地址要经过的第接到这个消息后便知道了到达目的地址要经过的第1 1个路由器的地个路由器的地址。址。2 2）接下来，源向目的地址发送）接下来，源向目的地址发送3 3个个TTLTTL2 2的数据包，于是，第一的数据包，于是，第一个路由器收到该包后改其个路由器收到该包后

27、改其TTLTTL1 1并转发给第并转发给第2 2个路由器，第个路由器，第2 2个路个路由器改其由器改其TTLTTL0 0，并向源发一个并向源发一个ICMPICMP超时消息，源就知道了应经超时消息，源就知道了应经过的第过的第2 2个路由器的地址。个路由器的地址。3 3）最后，向目的地址发送）最后，向目的地址发送3 3个个TTLTTLn n且目的节点不认识的包，目且目的节点不认识的包，目的节点就向源发回一个目的地址不可达的的节点就向源发回一个目的地址不可达的ICMPICMP消息，于是，源就消息，于是，源就知道自己已到达了最终目标。知道自己已到达了最终目标。4 4）依据上述原理，源就知道了到达目的地

28、址应经过的各个路由器）依据上述原理，源就知道了到达目的地址应经过的各个路由器的地址。的地址。2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-39地址解析协议地址解析协议地址解析协议地址解析协议172.16.3.1172.16.3.2IP:172.16.3.2=?I need the Ethernet address of 176.16.3.2.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-40地址解析协议地址解析协议地址解析协议地址解析协议172.16.3.1172.16.3.

29、2IP:172.16.3.2=?I heard that broadcast.The message is for me.Here is my Ethernet address.I need the Ethernet address of 176.16.3.2.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-41地址解析协议地址解析协议地址解析协议地址解析协议172.16.3.1IP:172.16.3.2 Ethernet:0800.0020.1111 172.16.3.2IP:172.16.3.2=?I heard that broa

30、dcast.The message is for me.Here is my Ethernet address.I need the Ethernet address of 176.16.3.2.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-42地址解析协议地址解析协议地址解析协议地址解析协议Map IP EthernetLocal ARP172.16.3.1IP:172.16.3.2 Ethernet:0800.0020.1111 172.16.3.2IP:172.16.3.2=?I heard that broadcast.The

31、 message is for me.Here is my Ethernet address.I need the Ethernet address of 176.16.3.2.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-43反向反向反向反向 ARPARPEthernet:0800.0020.1111 IP=?What is my IP address?2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-44反向反向反向反向 ARPARPEthernet:0800.0020.11

32、11 IP=?What is my IP address?I heard that broadcast.Your IP address is 172.16.3.25.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-45反向反向反向反向 ARPARPEthernet:0800.0020.1111IP:172.16.3.25Ethernet:0800.0020.1111 IP=?What is my IP address?I heard that broadcast.Your IP address is 172.16.3.25.2004,C

33、isco Systems,Inc.All rights reserved.ICND 2.00-46反向反向反向反向ARPARPMap Ethernet IPEthernet:0800.0020.1111IP:172.16.3.25Ethernet:0800.0020.1111 IP=?What is my IP address?I heard that broadcast.Your IP address is 172.16.3.25.2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-47总结总结通过完成本章学习通过完成本章学习,你可以完成

34、以下任务你可以完成以下任务:识别识别 TCP/IP 协议栈并描述每层的功能协议栈并描述每层的功能将将IP地址分成几个部分描述地址分成几个部分描述:网络号网络号,子网号子网号,和主机地址部分和主机地址部分在在Cisco的路由器和交换机上配置的路由器和交换机上配置IP地址地址 2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-48问题回顾问题回顾1.在传输层里在传输层里,TCP协议和协议和UDP协议有什么不同协议有什么不同?2.给定一个主机地址给定一个主机地址,192.168.20.1 255.255.255.240,在这个子网内还有其他多少个主机在这个子网内还有其他多少个主机地址可用地址可用?2004,Cisco Systems,Inc.All rights reserved.ICND 2.00-49