CCNA_第二章基于TCPIP的互连网络

©1999,CiscoSystems,Inc.8-1第二章基于TCP/IP的互连网络©1999,CiscoSystems,Inc.—8-2通过本章的学习，您应该掌握以下内容：•了解TCP/IP协议栈，各个分层的主要功能、IP协议的应用•掌握IP地址分类，子网掩码的作用，识别网络标识号、主机标识号，子网的数目•学会在路由器的端口正确设置IP地址和子网掩码•用路由器连接两个不同的VLAN实现通讯本章目标©1999,CiscoSystems,Inc.—8-3早期的协议族全球范围TCP/IP介绍主机InternetTCP/IP主机©1999,CiscoSystems,Inc.—8-4TCP/IP协议族7654325432应用层表达层会话层传输层网络层数据链路层物理层1应用层传输层Internet层数据链路层物理层1©1999,CiscoSystems,Inc.—8-5应用层概述*路由器使用应用层传输层Internet层数据链路层物理层文件传输-TFTP*-FTP*E-Mail-SMTP*远程登陆-Telnet*网络管理-SNMP*名称管理-DNS*©1999,CiscoSystems,Inc.—8-6传输层概述TransmissionControlProtocol(TCP)UserDatagramProtocol(UDP)应用层传输层Internet层数据链路层物理层面向连接非面向连接©1999,CiscoSystems,Inc.—8-7TCP数据格式Sourceport(16)Destinationport(16)Sequencenumber(32)Headerlength(4)Acknowledgementnumber(32)Reserved(6)Codebits(6)Window(16)Checksum(16)Urgent(16)Options(0or32ifany)Data(varies)20BytesBit0Bit15Bit16Bit31©1999,CiscoSystems,Inc.—8-8端口号TCP端口号FTP传输层TELNETDNSSNMPTFTPSMTPUDP应用层2123255369161RIP520©1999,CiscoSystems,Inc.—8-9TCP端口号源端口目标端口…HostA102823…SPDPHostZTelnetZ目标端口=23.©1999,CiscoSystems,Inc.—8-10发送SYN(seq=100ctl=SYN)接收SYNHostAHostBTCP三次握手1©1999,CiscoSystems,Inc.—8-11发送SYN(seq=100ctl=SYN)接收SYN发送SYN,ACK(seq=300ack=101ctl=syn,ack)HostAHostB接收SYN12TCP三次握手©1999,CiscoSystems,Inc.—8-12发送SYN(seq=100ctl=SYN)接收SYN发送SYN,ACK(seq=300ack=101ctl=syn,ack)建立会话(seq=101ack=301ctl=ack)HostAHostB123接收SYNTCP三次握手©1999,CiscoSystems,Inc.—8-13TCP简单确认滑动窗口=1发送方接收方©1999,CiscoSystems,Inc.—8-14TCP简单确认滑动窗口=1发送方接收方发送1接收1©1999,CiscoSystems,Inc.—8-15TCP简单确认滑动窗口=1发送方接收方发送1接收1接收ACK2发送ACK2©1999,CiscoSystems,Inc.—8-16TCP简单确认滑动窗口=1发送方接收方发送1接收1接收ACK2发送ACK2发送2接收2©1999,CiscoSystems,Inc.—8-17TCP简单确认滑动窗口=1发送方接收方发送1接收1接收ACK2发送ACK2发送2接收2接收ACK3发送ACK3©1999,CiscoSystems,Inc.—8-18TCP简单确认滑动窗口=1发送方接收方发送1接收1接收ACK2发送ACK2发送2接收2接收ACK3发送ACK3发送3接收3©1999,CiscoSystems,Inc.—8-19滑动窗口=1发送方接收方发送1接收1接收ACK2发送ACK2发送2接收2接收ACK3发送ACK3发送3接收3接收ACK4发送ACK4TCP简单确认©1999,CiscoSystems,Inc.—8-20TCP顺序号和确认号源端口目标端口…顺序号#确认号#SourceDest.Seq.Ack.102823101我发送#10.©1999,CiscoSystems,Inc.—8-21TCP顺序号和确认号我已收到#10,现在我需要#11.源端口目标端口…顺序号#确认号#102823SourceDest.10Seq.1Ack.102823SourceDest.11Seq.1Ack.我发送#10.©1999,CiscoSystems,Inc.—8-22TCP顺序号和确认号源端口目标端口…顺序号#确认号#102823SourceDest.11Seq.2Ack.102823SourceDest.10Seq.1Ack.102823SourceDest.11Seq.1Ack.我已收到#10,现在我需要#11.我发送#10.©1999,CiscoSystems,Inc.—8-23TCP顺序号和确认号源端口目标端口…顺序号#确认号#102823SourceDest.11Seq.2Ack.102823SourceDest.10Seq.1Ack.102823SourceDest.11Seq.1Ack.102823SourceDest.12Seq.2Ack.我已收到#11,现在我需要#12.我发送#11©1999,CiscoSystems,Inc.—8-24TCP窗口发送方接收方©1999,CiscoSystems,Inc.—8-25TCP窗口Windowsize=3Send2发送方接收方Windowsize=3Send1Windowsize=3Send3©1999,CiscoSystems,Inc.—8-26Windowsize=3Send2TCP窗口发送方Windowsize=3Send1Windowsize=3Send3ACK3Windowsize=2数据3被丢弃接收方©1999,CiscoSystems,Inc.—8-27Windowsize=3Send2TCP窗口发送方Windowsize=3Send1Windowsize=3Send3ACK3Windowsize=2数据3被丢弃Windowsize=3Send4Windowsize=3Send3接收方©1999,CiscoSystems,Inc.—8-28Windowsize=3Send2TCP窗口发送方Windowsize=3Send1Windowsize=3Send3ACK3Windowsize=2数据3被丢弃Windowsize=2Send4Windowsize=2Send3ACK5Windowsize=2接收方©1999,CiscoSystems,Inc.—8-29没有顺序号和确认号UDP数据格式Sourceport(16)Destinationport(16)Length(16)Data(ifany)1Bit0Bit15Bit16Bit31Checksum(16)8Bytes©1999,CiscoSystems,Inc.—8-30Internet层概述OSI网络层对应的是TCP/IP的internet层InternetProtocol(IP)InternetControlMessageProtocol(ICMP)AddressResolutionProtocol(ARP)ReverseAddressResolutionProtocol(RARP)应用层传输层Internet层数据链路层物理层©1999,CiscoSystems,Inc.—8-31IP数据Version(4)DestinationIPAddress(32)Options(0or32ifany)Data(variesifany)1Bit0Bit15Bit16Bit31HeaderLength(4)Priority&TypeofService(8)TotalLength(16)Identification(16)Flags(3)Fragmentoffset(13)Timetolive(8)Protocol(8)Headerchecksum(16)SourceIPAddress(32)20Bytes©1999,CiscoSystems,Inc.—8-32决定上层协议协议域TransportLayerInternetLayerTCPUDPProtocolNumbersIP176©1999,CiscoSystems,Inc.—8-33ICMP协议ApplicationTransportInternetDataLinkPhysicalDestinationUnreachableEcho(Ping)OtherICMP1©1999,CiscoSystems,Inc.—8-34ARP协议172.16.3.1172.16.3.2IP:172.16.3.2=???我需要知道172.16.3.2的物理地址.©1999,CiscoSystems,Inc.—8-35ARP协议172.16.3.1172.16.3.2IP:172.16.3.2=???我知道你的请求，这是我的物理地址我需要知道172.16.3.2的物理地址.©1999,CiscoSystems,Inc.—8-36ARP协议172.16.3.1IP:172.16.3.2Ethernet:0800.0020.1111172.16.3.2IP:172.16.3.2=???我知道你的请求，这是我的物理地址我需要知道176.16.3.2的物理地址.©1999,CiscoSystems,Inc.—8-37ARP协议映射IPEthernetLocalARP172.16.3.1IP:172.16.3.2Ethernet:0800.0020.1111172.16.3.2IP:172.16.3.2=???我知道你的请求，这是我的物理地址我需要知道172.16.3.2的物理地址.©1999,CiscoSystems,Inc.—8-38RARP协议Ethernet:0800.0020.1111IP=?