單區(qū)域OSPF協(xié)議及SPF算法

路由原原理第二課課單單區(qū)區(qū)域OSPF協(xié)議及及SPF算法課程目目標(biāo)通過本本課的的學(xué)習(xí)習(xí)，讓讓學(xué)生生掌握握OSPF的特性性，OSPF單區(qū)域域基本本配置置，并并了解解spf算法的的特點(diǎn)點(diǎn)本課內(nèi)內(nèi)容1.1：?jiǎn)螀^(qū)區(qū)域OSPF協(xié)議的的配置置以及及工作作機(jī)制制1.2：什么么是最最短路路徑優(yōu)優(yōu)先算算法（（SPF）OSPF單區(qū)域域配置置routerospfprocess-id[vrfvpn-name]Router(config)#開啟OSPF路由進(jìn)進(jìn)程OSPF基本配配置networkip-addresswildcard-maskareaarea-idRouter(config-router)#定義OSPF將運(yùn)行行在哪哪個(gè)接接口Router(config-if)#ipospfprocess-idareaarea-id[secondariesnone]在指定定的接接口啟啟用OSPF單區(qū)域?qū)嶒?yàn)驗(yàn)要求任務(wù)：OSPF單區(qū)域的配配置配置loopback地址作為路路由器的ID配置OSPF的進(jìn)程并在在相應(yīng)的接接口上啟用用完成成標(biāo)標(biāo)準(zhǔn)準(zhǔn)可以以ping通各各路路由由器器的的loopback地址址showrun時(shí)可可以以查查看看到到每每臺(tái)臺(tái)路路由由器器所所屬屬的的區(qū)區(qū)域域OSPFRouterID運(yùn)行行OSPF的路路由由器器之之間間是是通通過過OSPF的routerID來相相互互識(shí)識(shí)別別的的LSDBs使用用OSPFrouterID來區(qū)區(qū)分分路路由由器器默認(rèn)認(rèn)，，OSPF的routerID是使使用用被被激激活活的的接接口口的的最最高高的的ip地址址如果果有有l(wèi)oopbackinterface那么么它它將將成成為為OSPFrouterID如果果有有多多個(gè)個(gè)loopbackinterface那么么將將選選擇擇其其中中ip地址址最最大大的的可以以使使用用命命令令配配置置指指定定的的OSPFrouter-idRouter(config)#interfaceloopback0Router(config-if)#ipaddress172.16.17.5255.255.255.255如果果OSPF的進(jìn)進(jìn)程程已已經(jīng)經(jīng)運(yùn)運(yùn)行行的的時(shí)時(shí)候候，，想想更更改改RouterID則必必須須要要重重新新啟啟動(dòng)動(dòng)OSPF的進(jìn)進(jìn)程程，，才才能能使使新新的的RouterID生效效LoopbackInterfacesrouter-idip-address配置置OSPFrouter-id命令令Router(config-router)#Router(config)#routerospf1Router(config-router)#router-id172.16.1.1Router#clearipospfprocessclearipospfprocessRouter#OSPFRouterID驗(yàn)證RouterB#shipospfRoutingProcess"ospf50"withID10.64.0.2<outputomitted>Numberofareasinthisrouteris2.2normal0stub0nssaNumberofareastransitcapableis0Externalfloodlistlength0AreaBACKBONE(0)AreaBACKBONE(0)AreahasnoauthenticationSPFalgorithmlastexecuted00:01:25.028agoSPFalgorithmexecuted7times<outputomitted>Area1Numberofinterfacesinthisareais1AreahasnoauthenticationSPFalgorithmlastexecuted00:00:54.636agoSPFalgorithmexecuted3times<outputomitted>showipprotocolsRouter#OSPF的檢驗(yàn)showiprouteospf[process-id]Router#showipospfinterface[typenumber]Router#showipospfRouter#OSPF的檢驗(yàn)showipospfneighbor[typenumber][neighbor-id][detail]Router#例：showiprouteospfRouterA#showiprouteospf10.0.0.0/8isvariablysubnetted,3subnets,2masksOIA10.2.1.0/24[110/782]via10.64.0.2,00:03:05,FastEthernet0/0RouterA#例：showipospfinterfaceRouterA#showipospfinterfacefastEthernet0/0FastEthernet0/0isup,lineprotocolisupInternetAddress10.64.0.1/24,Area0ProcessID1,RouterID10.64.0.1,NetworkTypeBROADCAST,Cost:1TransmitDelayis1sec,StateDROTHER,Priority0DesignatedRouter(ID)10.64.0.2,Interfaceaddress10.64.0.2NobackupdesignatedrouteronthisnetworkTimerintervalsconfigured,Hello10,Dead40,Wait40,Retransmit5oob-resynctimeout40Helloduein00:00:04SupportsLink-localSignaling(LLS)Index1/1,floodqueuelength0Next0x0(0)/0x0(0)Lastfloodscanlengthis1,maximumis4Lastfloodscantimeis0msec,maximumis4msecNeighborCountis1,Adjacentneighborcountis1Adjacentwithneighbor10.64.0.2(DesignatedRouter)Suppresshellofor0neighbor(s)例:TheshowipospfneighborRouterB#showipospfneighborNeighborIDPriStateDeadTimeAddressInterface10.64.0.10FULL/DROTHER00:00:3010.64.0.1FastEthernet0/010.2.1.10FULL/-00:00:3410.2.1.1Serial0/0/1RouterB#showipospfneighbordetailNeighbor10.64.0.1,interfaceaddress10.64.0.1Inthearea0viainterfaceFastEthernet0/0Neighborpriorityis0,StateisFULL,16statechangesDRis10.64.0.2BDRis0.0.0.0<outputomitted>Neighbor10.2.1.1,interfaceaddress10.2.1.1Inthearea1viainterfaceSerial0/0/1Neighborpriorityis0,StateisFULL,6statechangesDRis0.0.0.0BDRis0.0.0.0<outputomitted>Dijkstra算法Dijkstra算法是路路由表計(jì)計(jì)算的依依據(jù)，通通過Dijkstra算法可以以得到有有關(guān)網(wǎng)絡(luò)絡(luò)節(jié)點(diǎn)的的最短路路徑樹，，然后由由最短路路徑優(yōu)先先樹得到到路由表表。SPF算法有時(shí)時(shí)也被稱稱為Dijkstra算法，這這是因?yàn)闉樽疃搪仿窂絻?yōu)先先算法SPF是Dijkstra發(fā)明的。。Dijkstra算法SPF算法將每每一個(gè)路路由器作作為根（（ROOT）來計(jì)算算其到每每一個(gè)目目的地路路由器的的距離，，每一個(gè)個(gè)路由器器根據(jù)一一個(gè)統(tǒng)一一的數(shù)據(jù)據(jù)庫(kù)會(huì)計(jì)計(jì)算出路路由域的的拓?fù)浣Y(jié)結(jié)構(gòu)圖，，該結(jié)構(gòu)構(gòu)圖類似似于一棵棵樹，在在SPF算法中，，被稱為為最短路路徑樹。。在OSPF路由協(xié)議議中，最最短路徑徑樹的樹樹干長(zhǎng)度度，即OSPF路由器至至每一個(gè)個(gè)目的地