ospf邻接建立详细过程(包括五报文七状态)

5、ospf邻接建立过程描述:12.1.1.2/24ik> :12.1.1.2/24I IR2首先总结下五报文和七状态l.Down 路由器还末收到邻居发来的HELLO包（1.5）在NBMA还有个attempt（尝试状态）：为NBMA网络中的一个正常过滤状态，即我发送了HELLO等待对方的回应，如果对方不回应则一直滞留在此状态。2.init 收到来自邻居的hello包，但是hello中未包含自身的信息。two-way路由器在收到邻居发来的HEELO包中，看到自己的ROUTER-ID，在这个态开始选举DR和BDRexstart 在选举DR和BDR之后，开始选主从Master/Slaveexchange主从协商完成后，进行DBD的同步，链路数据库描述（DBD）6.loadingDBD同步完成后，进行LSA的同步7.full LSA同步完成之后根据上图做实验分析：在R1和R2启用ospf后，会组播向外发送hello报文。廓2319:53:13.019:OSPF:Sendhel1oto224.0.0.5area0onFastEtherietl/Ofrom12.L.1.1一一jr j-i tl、_田internetProtocolversion4,src:12.1.1.Z(12.1.1.2),Dst:224.0.0.5(224BopenshortestPathFirst日ospfHeaderospfversion:2MessageType:He!1□Packex(1)PacketLength:44SourceOSPFRouter:2.2.2.2(2.2.2.2)AreaID：0.0.0.0(Backbone)Packetchecksum:0xdb97[correct]AuthType:NullAuithData(none)□ospfHe!1□PacketNetworkMask:255.255.255.0He!1□Interval:10seconds田options:0x12(L,E)RouterPriority:1Routerdeadinterval:40secondsDesignatedRouter:12.1.1.2BackupDesignatedRouter:0.0.0.0@ospfllsDataBlockU1111.54000012.1.L.1224.&.0.5OSPF94HelloPacketE)Frame11:54bytesonwiite(752bits),54bytescapxured(752bits)0EthernetII,Src:ca:00:1c:10:0Q:lcCea:00:1c:10:00:1c),Dst:IPv4mci0IniternetProtocolVersnon4,Src:12.1.1.1<12.1.1.1),Dst:224.0.0.!BopenshortestFathFlrsr□ospfHeaderO5FFversion:2MessageType:Hel1oPacket《1)PacketLength:48sourceospfRouter:1.1.1.1(1.1.1.1)AreaID：0.0.0.0(Backbone)Packetchecksum:OxccSf[correct]AuthType:NullAuthData(none)日ospfHelloPacketNetworkMask:255.255.255.0Hellciinterval:10secondsqopfions:0x12(l,e)RouterPriority:1RouterDeadinxerv-al:40seccndsDesignatedRouter:12.1.1.2BackupDesignatedRouter:12.1.1.1AcfiveNeighbor:2.2.2.20QSPFLLSDataBlock■8L0.02000012.1.1.2224.0.0.5OSPF94HellePacketFram^E:3-4bytesonwire(752bits^a54bytescaptured(752hits)(3EthernetII,src:cji：ai:lc:10：aD:lc(ca:01:1c:10:00:1c),Dsr:IPv4me@internetProTocolversion4,src:12.1.1.2(12.1.1.2),Dsr：2Z4.0.0.□openshartesTPathFirst□O5PFHeaderospfversion:2MessageType:HelloPacketQL)PacketLength:4BSourceOSPFRouter:2.2.2.2(2.2.2.2)AreaID：0.□.0.0(Backbone)Packetchecksum:0xd991[carrect]AuthType:HullAuthData(门one)日O5PFHe!1□PacketNetworkMask:255,55.N55.Qne"l1ointerval:10seconds田opfions:OxlZ(L,匚)RouterPriority:1RouterD^adinxeirval:40secondsDesignatedfTouter:12.1.1.2BackupDesignatedRouter:0.0.0.□AcfiveNeighbar:1.1.1.10O5PFLLSDataBlockactiveneighbor字段中为R1的ROUTER-ID1.1.1.1和2.2.2.2,说明进入TWO-WAY状态，并且开始选举DR和BDRistrativestateDown*Mar2319:5S:11.567:OSPF:Revhe!1ofrom1.1.1.1area0fromFastEthernetl/O11'Mar2319:58:11.567:OSPF:2WayConimunicationto1.1.1.1onFastEthernetl/O,szate2WAY '"Mar2319:^8:11.b7.L:ospf:backupseenEventbeforewaittimeronFastEthernet1*Mar?31Q::11.571:OSPF:DR/RDBelectiononFastEthernetl/O也ar2319:58:11.571:OSPF：ElectBDFl2.2.2.2*Mar2319:58:11.571:OSPF：ElectDR1.1.1.1'Mar2319：58：11.571:CiSPF：LlCCLEDR2.2.2.22319：5S：11.575：OSPF：ElectDR1.1.1.1*Mar2319：58：11-口5： DR：1.1.1.1fid)RDR:2.2.7.2Ud)选举完成后开始转为extart状态进入exstartstate，开始选主从(ROUTER-ID大的为主，作用为了同步DBD的序列号)R1和R2分别向外发DBD报文，都认为自己为主：如图f3f33233222522(carx5araroararoxararx52MoMMtMMMMf3f33233222522(carx5araroararoxararx52MoMMtMMMMotEEE3bs--vsMs7--X8O599a16180-5a:i—9fI3X.-o_9a-I—f_2.579:OSPF:SendDBDto1.1.1.1onFastEthernetl/Oseq0x4A6opten32.579:OSPF:RetransmitfingDBDto1.1.1.1on-astEthernetl/O[1].607:OSPF:RevDBDfrom1.1.L.1onFastEtherietl/OseqOxZOMo1tn32mrtu1500stateEXSTART.607:ospf：Firstdbdandwearenotslave.631:OSPF:RevDBDfrom1.1.L.1onFastEtherietl/0seq0x4A6oplen52mrtu1300stateEXSTART.ospf：nbrNegotiationDone,wearethemaster.631:ospi-:senddbdto1.1.1.1onFastEtherneti/oseq0X4A7opten52在DBD中IMMS分别表示第一个包、M表示后面还有几个包MS表示为主InterfaceMTU：在不分片的情况下，此接口最大可发出的IP报文长度为1500。I（Initial）：当发送连续多个DD报文时，如果这是第一个DD报文，则置为1，否则置为0。M（More）：当连续发送多个DD报文时，如果这是最后一个DD报文，则置为0。否则置为1，表示后面还有其他的DD报文。MS（Master/Slave）：当两台OSPF路由器交换DD报文时，首先需要确定双方的主（Master）从（Slave）关系，RouterID大的一方会成为Master。当值为1时表示发送方为Master。Fr-ane79s76bytesdhwire(624 ,73byrescapcurad(624birs)Erherrrei：llbarcs-ca：aiE16:E4-]QO31ctea[01:16\M100:1c)fe。耳cajODiInterrwtPrcrtocol*ta「s:iciri47Src:12.1.1.2(li.l.1-2)Fiatie30ibyresonwire(fi24b1is),75byresc-aprured(€?4b1rs)echeniern,src!caiD0：lfii-g4!DO^lc(t-asOD:Fiatie30ibyresonwire(fi24b1is),75byresc-aprured(€?4b1rs)echeniern,src!caiD0：lfii-g4!DO^lc(t-asOD:16：84i00!1c),dst.!caiOl!nrernetppold匚olversion4,src:12.1.1.1(12.1.1.1),ts-r:12.1.1.2OpenShortest:PathFirsrElOSPFneaderBOSPFDEOes-criprioninterfaceMTU31SD0@OpriOTIS:0X52(0,LfcE)■3DB0€Scrip-cion:0x07(I,MS)i.uOuiu=Rs(MBResyncbitisNOTsethli4-I;LnitbitisSET 1.-M;MorebitisSET 1-MS;Piaster/SlavebitisSETDDSequence;8356O5PFLLSggSlockChecksum:Oxfff6llsgmLer^gih:12byr^sSospfdbDescrliprldhInterfacemtu；1500E»opr1ons:0x52(a,l„e}QDBDescription:OxQZ(IFH(M5)....0...-r：ao&Resyncb~lr1smotseru--.al.u=I:Initbit1s5ET 1.-M:MarebitisSETu.u.--.1=MS;MasteravsbitisSETDDSequence:1190BO5PFLL5D3LABlockCtecksu■:Oxfff6llsdstaLengrh:12byres通过比较ROUTERID,R2的ID大所以成为主，R1成为备，R1使用R2的序列号1190发送LSA的头部信息给R2(I=0,M=1,MS=0)不为第一个包，后面还有包，为从。在BDB的主从协商完毕就进入了exchange状态了。05PF!NBRNegotiationDone.启aretheMASTERaHar2319E5B]16u6Jl:OSPF:SendD6Dta onFas^Ethernetl/Dseq0x52flagQx31eni52sKiar2319:5E：16.6J1:DSPF!Carabaserequestto1.1.1.12219：5BH6.6J1!DSPF!sentLSR£QpackettD12.1.1.1,length12=-Mar2319：5E!!16.643!DSPF:KcvDBDfrom1.1.1.1onFastEthenreizl/0seecflag0^01en12nrtu1500srareexchangeFrameSI:98onwHeC7&4bits)fc98bytescapturedN84bits)£rhernetII,Src:ca:00:16:&4:DO:1c(ca:00:16:0D:lc^(Dst:ca:01IntermetProtacnlverslon4,£rc:12.1.1.1(12.1.1.1),Ost:12.l.l.；openstories!pathFlrsr1田OSPFHeader日OSPFDEtescriptionimerfacemile1500Sopri□<!£!o»52(a,l.E)□neoescripiion:0x02Cm)-・~・0...-R:;ODBUesyncbitisNOTset……u0..=I:InitbitisNOTset 1.=MzMorebirisSET 0-MS:Master/filavabit:isnCitsetddsequertce:1190日LSAHeaderLSAg-e:;304secondsDaNetFalseR2收到R1发来的DBD中的LSA头部信息，同时向R1发送DBD报文，携带LSA的头部。(I=0,M=1,MS=1)不为第一个包，后面还有包，为主，序列号+1为1191FrameSS2:凹吕bytesonr-eQ/84bits)?bytescaptured曲bits-；EiherriieLn.src:ca：01U5：S4：00：lcCca：Ql:16：B4：oo；:lc),eel:ca:。。；:：interneTProracolVersion4asrc!12.1.1.2(12.1.1.2),Dsr:12.1.1.1OpenShortestPathFirstaC£PFheaderFCSPFCBDescriptioniimerfaceeu:1500aOptions30x52(O3L』E)□osDescripLion:&stO3(Mams)...-0...-R:MBResyncbitisNOTset・・・..D..■工:initblc1snotset 1.—iM:MoreLTeisSET 1 -MS;Master/51auebitisSETDOSequence：!1191RLSAHeaderlsAge:7secondsDoNetAge:False同时R2先知道自己的数据库是否同步，所以发送LSR，请求没同步的LSAinr«rn«EproTOC.01 A,arc:12-1.1-2<12.1.1.23,ckt:i12.1.1.1■Openglicir<estP-athFirst-iOSPFHaactarO5FPvfirslionj2MessageTypbeiLSReEjucst(1)Pi&ck«cL4ngrhz3-5sourceospfRouir*er:2.2.2.2<2.2»2.2)■「屿白ID;DnQ.gDQ-(Barekbo^M!)parck«cchacksuri!OmT5cf[corr«ciE]|*wthType;HullAuthDataCnane)BLink5Tac-«n.iHiuAitLin^-Stite也TypriRCT.iter-LSA(L)LinkStataID:1.1.1.1Ac^ertfslnsRomrtr:1.1,1.!(i.1«1.1)ji- 一. iR1收到R2发过来的BDB，要发送DBD的确认给DBD的主路由器也就R2，同时R1没有DBD的包了，所以M=0，表示为最后一个DBD包。(但如果主再发DBD包过来，并且从的路由器还是要发DBD进行确认，这叫隐式确认)I-*lKJf/JfL.ILN [U|ILtfcj□DBDescriptdon:OxQO.,,,0...=R：ooBResyncbic1snotser・--，.O..—r:InitbitisNOTsetau□.a.Oa=M]MoirebitisNOTset O=MS:rMasrer/SiavebdtisNOTsecddsequence:119^1

然后R1也开始想R2请求数据库同步信息Ecr^mfiiT：xi,srcica:uu:it::uu:zce.cb ikt: ::iiTCcrriftrprorcKOlg「±"ior】*.crcil2>iullC12.Lii«l)osciJnii2cp«rchortesrelrsc:;oepfHc&dcrosrr-versidHi2iMt55a>fl*!：Type; ■七*<3>r-ick«LenflThs3e50UTCC HOirtETI!.!■1.1fl.1.1.1)Art-BID1；QrOCi.OCD»CkbDn<>H*ck«：CMeckSUn；OK^Scd[correct]AmhType:Hu11AuehOjiex<nm-ivjl-jl-1rUc£ejit»R«qu«H±Lirfc-£t>t-vAdvm-E1■MTMitTypv:Rxiut»r-L£4fl]L-ir*«SturaZD:2.2.2.2Adv-nrtialngR-ourtrnr:^.2.2.2£2.2.2-3)R1先收到R2的请求，然后给R2回复信息updaterranuB7:110bytasanuir«{fl&Jbits),11nbytxc^pcurad(£30bits；EtherrwTII.£rc:cizlbD:M:lc£ci:Di3:lfl':B4 Dsc:ca:Dl::IntftrrwiProtKDlVnrslnnLEre:U-L.L-1(12.1-1.1J,Dsc:12.1.1.2OpenfiercestPathFinefEOSPFHEaderEiLSLfidacePackecHLirbcrofL£as:ILiLSType:Raurter-LSAl£4ge:3D5^eenndaGorwc4ge:False@Options;0x22(DC,E)l'Ink-StareAdvertiserrent7>pe:ftmjctr-LSAfL)LinkStateID-;1.1.1.1Advertisingftouc-Er;L.LL.L{X-L-LtL}LSSequenc-ENunb-tr:Ow&QOOOQOJL5di«kfun;0区&崩bLengths4^.R2收到R1发来的LSU要对收到的LSU进行确认，发送LSACK叫做显式确认。LSAck报文用来对接收到的LSU报文进行确认，内容是需要确认的LSA的Header。一个LSAck报文可对多个LSA进行确认。LSAHeaders:该报文包含的LSA头部。同时接收到R1的LSR请求，发送LSUFrate95Frate95：独b尖够岫F"(7fl<hlisj.用byrestapT^-id{7flibiis)Echernezle,sre:c3：iJL：15：fli：aa：k(c-a：Ql:i6:fl4：OO^lc.hkc:iFvlttLincerneiproiocfllversion4,sre:12.1.1.2(12,1.1.2)^晓口NL0O・.sDpensIwiesTparhFlrsi田05PFH£就归0LSALSA^fi:345泗EdSDowt推：False3apciWB:I]x22<K.,E)Link-sriTs.AdvertType:routw-lsa(1)Linksiiieid:i.L.l.L.Advfriisingrouce^：L.L1.1(Ll.LL)LS料HtKQHui*b^:Ojl££I000002L5ChKkSur：Q涌的Length：430LSAlsA^e：1secondsFrame94:73bytesonwire(624bits)H75byrescapcured(-624b1rs)Etha-netII,sre:ca：0D：L6：34:00:1c(csiODilbiaJiaoiicJ,Dst:iFvlnInternetPraiKolVersion4,S'c:L2-L.1.1(12.1.1.1),Csc:224.D.0qpenshorcesiPirliFirsi:IDO5FFHeader□L5AHeaderlsAge:8sown的DONotAge；Ffllsfl国Options;Qk22(DC,E)Lirii-StateAdvertisenerritType;Raut-er-LS^Cl)LirfcStateID;2>2-2.2Adv-firtisingRouter2-2.2.2{2.2.2-2)LSS€qu^HC€UUHberZ0XBaDM002lSChecksunr:QxidbsLenqrh:4B等到R2没数据包了，要发送最后一个数据包告诉R1没数据包了，即M=0，并且R1还需要进行回复。umcarmicPfocikoIumcarmicPfocikoIvarsicn4,Src\12.1.1.2(12.1.1.2jpQst:12_]L.1_1CpenShnrttstF-athFirst0OSPFHE&kr005FFGGM5CfipClOhlnterf*ceWRi:IMO(BOptions；anz(0,L,E)□D£Dea