IP編址Page2前言網(wǎng)絡層位于數(shù)據(jù)鏈路層與傳輸層之間。網(wǎng)絡層中包含了許多協(xié)議，其中最為重要的協(xié)議就是IP協(xié)議。網(wǎng)絡層提供了IP路由功能。理解IP路由除了要熟悉IP協(xié)議的工作機制之外，還必須理解IP編址以及如何合理地使用IP地址來設計網(wǎng)絡。Page3學習目標

學完本課程后，您應該能：掌握IP報文的結(jié)構(gòu)掌握公有IP地址、私有IP地址以及特殊IP地址的范圍掌握VLSM技術(shù)理解網(wǎng)關(guān)的作用Page4上層協(xié)議類型DMACDataSMACTypeFCS6B6B2B46-1500B4B0x0800IP以太網(wǎng)幀中的Type字段值為0X0800，表示該幀的網(wǎng)絡層協(xié)議為IP協(xié)議。IP報文頭部Page5VersionDSFieldTotalLengthIdentificationFlagsFragmentOffsetTimetoLiveProtocolHeaderChecksumSourceIPAddressDestinationIPAddressIPOptions0 16 3120Bytes固定長度20-60BDataIPHeaderLengthIP編址Page6.1192.168.1.0000000111000000.10101000.00000001網(wǎng)絡位主機位IP地址分為網(wǎng)絡部分和主機部分。IP地址由32個二進制位組成，通常用點分十進制形式表示。IP編址Page7.0192.168.1.0000000011000000.10101000.00000001.255192.168.11111111111000000.10101000.00000001網(wǎng)絡地址廣播地址網(wǎng)絡位主機位網(wǎng)絡位主機位二進制、十進制和十六進制Page8進制字符范圍基值二進制

0—12十進制0—910十六進制0—9，A—F16在IP網(wǎng)絡中，二進制和十六進制是常用的編碼方式。十進制二進制十六進制000000000001000000010120000001002300000011034000001000450000010105600000110067000001110780000100008十進制二進制十六進制9000010010910000010100A11000010110B1200001100014000011100………25511111111FF進制之間轉(zhuǎn)換Page9比特位11111111乘方2726252423222120數(shù)值1286432168421二進制和十進制轉(zhuǎn)換Page10.1網(wǎng)絡位主機位192.168..100000001.11000000.10101000..000000012027+2627+25+2320二進制十進制IP地址分類Page11A類Host(24bit)B類C類D類E類128.0.0.0~191.255.255.255

192.0.0.0~223.255.255.255

224.0.0.0~239.255.255.255240.0.0.0~255.255.255.2550.0.0.0~127.255.255.255

0網(wǎng)絡位(8bit)主機位(24bit)10網(wǎng)絡位(16bit)主機位(16bit)110網(wǎng)絡位(24bit)主機位(8bit)1110組播1111保留IP地址類型Page12私有地址范圍10.0.0.0~10.255.255.255172.16.0.0~172.31.255.255192.168.0.0~192.168.255.255特殊地址127.0.0.0~127.255.255.2550.0.0.0255.255.255.255網(wǎng)絡通信Page13.1網(wǎng)絡位主機位192.168..0192.168.1.1192.168.1.2192.168.2.1192.168.2.2.2192.168..0主機A主機B主機C主機D子網(wǎng)掩碼Page14192.168.1.011000000.10101000.00000001.00000000網(wǎng)絡位主機位11111111.11111111.11111111.00000000255.255.255.0子網(wǎng)掩碼默認子網(wǎng)掩碼Page15A類B類C類255.0.0.0255.255.0.0255.255.255.0地址規(guī)劃Page16主機數(shù):

2n110000001010100000000001000000001100000010101000000000010000011111111111111111111111111100000000IP地址網(wǎng)絡地址(二進制)網(wǎng)絡地址192.168.1.7255.255.255.0子網(wǎng)掩碼256254可用主機數(shù):2n-2192.168.1.0地址規(guī)劃舉例Page17IP地址172.16.1.7主機數(shù):

2n可用主機數(shù):2n-2網(wǎng)絡地址255.255.0.0子網(wǎng)掩碼??????根據(jù)給出的IP地址和子網(wǎng)掩碼，請算出此網(wǎng)絡中包含的主機地址數(shù)量以及可用主機地址的數(shù)量。有類IP編址的缺陷Page18在設計網(wǎng)絡時使用有類IP地址會造成地址的浪費。192.168.1.0/24192.168.2.0/24192.168.3.0/2430個主機10個主機20個主機變長子網(wǎng)掩碼Page19110000001010100000000001000000001100000010101000000000010000011111111111111111111111111110000000IP地址192.168.1.7255.255.255.128子網(wǎng)掩碼主機數(shù):

2n網(wǎng)絡地址128126可用主機數(shù):2n-2192.168.1.0變長子網(wǎng)掩碼舉例Page20現(xiàn)有一個C類網(wǎng)絡地址段192.168.1.0/24，請使用變長子網(wǎng)掩碼給三個子網(wǎng)分別分配IP地址。30個主機10個主機20個主機無類域間路由Page2110.24.0.0/2410.24.2.0/2410.24.3.0/24通告路由10.24.0.0/2210.24.1.0/24CIDR增強了網(wǎng)絡的可擴展性。網(wǎng)關(guān)Page22主機A主機B192.168.2.1192.168.1.1192.168.1.253192.168.2.253網(wǎng)關(guān)用來轉(zhuǎn)發(fā)來自不同網(wǎng)段之間的數(shù)據(jù)包。IP包分片主機A主機BPage23VersionDSFieldTotalLengthHeaderChecksumSourceIPAddressDestinationIPAddressIPOptionsHeaderLengthProtocolTimetoLiveFragmentOffsetFlagsIdentification生存時間主機ATTL=255TTL=254TTL=253主機BPage24VersionDSFieldTotalLengthHeaderChecksumSourceIPAddressDestinationIPAddressIPOptionsHeaderLengthFragment

OffsetFlagsIdentificationProtocolTimetoLive協(xié)議號Page25IPDataProtocol6/17TCP/UDP1ICMPVersionDSFieldTotalLength