《TCPIP协议》PPT课件

.,1,第四章TCP/IP协议,.,2,第四章TCP/IP协议,TCP/IP协议概述TCP/IP协议模型应用层协议传输层协议网间层协议IP地址子网划分,.,3,TCP/IP,一组通信协议（传输协议）TransmissionControlProtocol/InternetProtocolTCP/IP协议的产生ARPANET,.,4,TCP/IP协议,RFC（RequestForComments）关于Internet和ARPANET的技术文档协议，概念的标准WWW.IETF.ORG,.,5,TCP/IP协议模型,.,6,TCP/IP模型OSI模型,.,7,DataFlow,.,8,TCP/IP协议集,.,9,TCP/IP体系结构,.,10,TCP/IP协议模型,.,11,TCP/IP应用层,HTTP/HTTPSFTPSMTPPOP3TelnetSNMPNNTP,.,12,TCP/IP传输层,TCPUDP,Application,Transport,Internet,HosttoNetwork,.,13,TCP,面向连接的协议Connection-Oriented可以保证数据传输的正确性建立连接传输机制HTTP,FTP等,.,14,UDP,非面向连接的协议Connectionless不能保证数据传输的正确性，靠上层保证无需建立连接，减少了通讯的开销可发送广播帧DNS寻址，SNMP等,.,15,TCP帧结构,012301234567890123456789012345678901+-+-+|SourcePort|DestinationPort|+-+-+|SequenceNumber|+-+|AcknowledgmentNumber|+-+-+-+|Data|U|A|P|R|S|F|Offset|Reserved|R|C|S|S|Y|I|Window|G|K|H|T|N|N|+-+-+-+|Checksum|UrgentPointer|+-+-+-+|Options|Padding|+-+-+|data|+-+,.,16,TCP帧结构,012301234567890123456789012345678901+-+-+|SourcePort|DestinationPort|+-+-+|SequenceNumber|+-+|AcknowledgmentNumber|+-+-+-+|Data|U|A|P|R|S|F|Offset|Reserved|R|C|S|S|Y|I|Window|G|K|H|T|N|N|+-+-+-+|Checksum|UrgentPointer|+-+-+-+|Options|Padding|+-+-+|data|+-+,.,17,包丢失避免,Sender,Receiver,Send1,ACK2,Send2,Send2,ACK2,SYN1,SYN2,SYN2,ACK3,第二个包没收到,.,18,建立连接,3-WayHandshakeforConnectionSynchronization交换初始序列号ISNA-BSYNmysequencenumberis1ABACKyoursequencenumberis130,.,19,用窗口进行流控制,.,20,用窗口进行流控制,.,21,UDP帧结构,012301234567890123456789012345678901+-+-+|SourcePort|DestinationPort|+-+-+|Length|Checksum|+-+|dataoctets.+-.,.,22,TCP/IP的传输层,端口号Port标识应用层某种具体的服务16bit0-655350-1023保留,.,23,TCP/IP的传输层,端口号Port标识某种具体的服务16bit0-1023保留0-65535套接字Socket标识应用程序间的连接TCPorUDP+IP+Port,.,24,常用的TCP端口号,端口号20FTPserver(datachannel)；21FTPserver(controlchannel)；23Telnetserver；25SMTPserver；80Webserver(HTTP)；110POP3server；139NetBIOSsessionservice,.,25,常用的UDP端口号,端口号53DNSnamequeries；69TrivialFileTransferProtocol(TFTP)；137NetBIOSnameservice；138NetBIOSDatagramservice；161SimpleNetworkManagementProtocol(SNMP)；520RoutingInformationProtocol(RIP),.,26,TCP和UDP的比较,服务性质传输可靠性传输开销，速度传输类型是否广播,.,27,Internet层,Application,Transport,Internet,HosttoNetwork,IPInternetProtocolICMPInternetControlMessageProtocolIGMPInternetGroupManagementProtocolARPAddressResolutionProtocolRARPReverseARP,.,28,ARP,AddressResolutionProtocol地址解析协议,.,29,ARP,IP-MAC解析广播ARPCacheARPa在路由器上察看ARPCache的命令清除ARPCache,.,30,RARP,ReverseAddressResolutionProtocol反地址解析协议MAC-IP获得广播RARP的应用场景,.,31,ICMP,InternetControlMessagesProtocol网间消息控制协议,.,32,ICMP,作用让发送者知道数据包传输过程中出现的问题必须被所有TCP/IP的主机实现是否用IP协议传输？应用PingEcho,EchoReply网络不可达DestinationUnreachable,.,33,.,34,IP协议,InternetProtocol,.,35,IP帧格式,012301234567890123456789012345678901+-+-+-+-+|Version|IHL|TypeofService|TotalLength|+-+-+-+-+-+|Identification|Flags|FragmentOffset|+-+-+-+-+|TimetoLive|Protocol|HeaderChecksum|+-+-+|SourceAddress|+-+|DestinationAddress|+-+-+|Options|Padding|+-+-+,.,36,IP帧格式,012301234567890123456789012345678901+-+-+-+-+|Version|IHL|TypeofService|TotalLength|+-+-+-+-+-+|Identification|Flags|FragmentOffset|+-+-+-+-+|TimetoLive|Protocol|HeaderChecksum|+-+-+|SourceAddress|+-+|DestinationAddress|+-+-+|Options|Padding|+-+-+,.,37,IP地址,逻辑地址，用于标识网络中的主机,.,38,IP地址,32位二进制数点分4组,每组8位每8位一个字节（byte）10101001.11111110.00000000.00000001,.,39,ConvertingtoBinaryFormat,.,40,IP地址,.,41,规定,NetID和HostID二进制位不能全0全1IPNetID本地广播55子网广播55,.,42,IPAddressClasses,.,43,IP分类,ClassA0 xxxxxxx.x.y.z1126.x.y.zClassB10 xxxxxx.x.y.z128191.x.y.zClassC110 xxxxx.x.y.z192223.x.y.zClassD1110 xxxx.x.y.z224239.x.y.zClassE11110 xxx.x.y.z240,.,44,ClassA,0 xxxxxxx.00000000.00000000.00000000,00000000.00000000.00000000,01111110.,,,网络号范围：,00000001.xxxxxxxx.xxxxxxxx.xxxxxxxx,00000001.,00000001.,主机范围:,,54,00000001.,00000000.00000000.00000000,00000000.00000000.00000001,11111111.11111111.11111110,.,45,ClassB,10 xxxxxx.xxxxxxxx.00000000.00000000,.00000000.00000000,10111111.11111111,,,网络号范围：,10000000.00000001.xxxxxxxx.xxxxxxxx,10000000.00000000.,10000000.00000000.,主机范围:,,54,10000000.00000000,.00000000.00000000,00000000.00000001,11111111.11111110,.,46,ClassC,110 xxxxx.xxxxxxxx.xxxxxxxx.00000000,.00000000,11011111.11111111.11111111,,,网络号范围：,11000000.00000000.00000000.xxxxxxxx,11000000.00000000.00000000.,11000000.00000000.00000000.,主机范围:,,54,11000000.00000000.00000000,.00000000,00000001,11111110,.,47,IP,网络数主机数A类27-22242B类2142162C类221282D类组播E类保留,.,48,特殊的IP地址,55,.,49,合法的主机IP?,555555,.,50,SubnetMask,子网掩码,.,51,SubnetMask,IP:SubnetMask:NetID:11000000.10101000.00000001.0000000111111111.11111111.11111111.0000000011000000.10101000.00000001.00000000,.,52,子网掩码的作用,区分NetworkID和HostID确定目标主机所在的网络“与”运算,.,53,SubnetMask,DefaultSubnetMaskClassA-ClassB-ClassC-,.,54,确定目标网络的过程,TCP/IP初始化时本机IP“与”本机子网掩码=本网络号发送数据时目标IP“与”本机子网掩码=目标网络号目标网络号和本网络号比较相同,说明在本网络不相同,数据包发往Gateway,.,55,数据帧格式,相同不相同,.,56,子网掩码表示法,一种新的子网掩码的表示法/24,.,57,CIDR表示法,ClasslessInter-DomainRouting(CIDR)不再遵从A,B,C类地址的缺省子网掩码/16/244/26,.,58,子网划分,.,59,子网划分,SubnettingIP子网(Subnet)不同访问技术的网络处于不同子网减少网络拥塞广播,.,60,借位原则,从HostID高位起划分子网借位连续最少要借2个二进制位子网ID不能全为0子网ID不能全为1,.,61,SubnetID,.xxxxxxxx.xxxxxxxx,.00.01.10.11,000000.00000000000000.00000000,,11111111.11111111.11000000.00000000,10000011.01101011.,131.107,SubnetMask:,.,62,SubnetID,10000011.01101011.01000000.00000000,000000.00000001,111111.11111110,10000011.01101011.01,10000011.01101011.01,主机范围：,,54,子网1:,IP：,11111111.11111111.11000000.00000000,Mask：,