單區(qū)域OSF協(xié)議及SF算法.ppt

第二課單區(qū)域OSPF協(xié)議及SPF算法 課程目標(biāo) 通過本課的學(xué)習(xí) 讓學(xué)生掌握OSPF的特性 OSPF單區(qū)域基本配置 并了解spf算法的特點(diǎn) 本課內(nèi)容 1 1 單區(qū)域OSPF協(xié)議的配置以及工作機(jī)制1 2 什么是最短路徑優(yōu)先算法 SPF OSPF單區(qū)域配置 routerospfprocess id vrfvpn name Router config 開啟OSPF路由進(jìn)程 OSPF基本配置 networkip addresswildcard maskareaarea id Router config router 定義OSPF將運(yùn)行在哪個(gè)接口 Router config if ipospfprocess idareaarea id secondariesnone 在指定的接口啟用OSPF 單區(qū)域?qū)嶒?yàn)要求 任務(wù) OSPF單區(qū)域的配置配置loopback地址作為路由器的ID配置OSPF的進(jìn)程并在相應(yīng)的接口上啟用完成標(biāo)準(zhǔn)可以ping通各路由器的loopback地址showrun時(shí)可以查看到每臺(tái)路由器所屬的區(qū)域 OSPFRouterID 運(yùn)行OSPF的路由器之間是通過OSPF的routerID來相互識(shí)別的LSDBs使用OSPFrouterID來區(qū)分路由器默認(rèn) OSPF的routerID是使用被激活的接口的最高的ip地址如果有l(wèi)oopbackinterface那么它將成為OSPFrouterID如果有多個(gè)loopbackinterface那么將選擇其中ip地址最大的可以使用命令配置指定的OSPFrouter id Router config interfaceloopback0Router config if ipaddress172 16 17 5255 255 255 255 如果OSPF的進(jìn)程已經(jīng)運(yùn)行的時(shí)候 想更改RouterID則必須要重新啟動(dòng)OSPF的進(jìn)程 才能使新的RouterID生效 LoopbackInterfaces router idip address 配置OSPFrouter id命令 Router config router Router config routerospf1Router config router router id172 16 1 1Router clearipospfprocess clearipospfprocess Router OSPFRouterID驗(yàn)證 RouterB shipospfRoutingProcess ospf50 withID10 64 0 2Numberofareasinthisrouteris2 2normal0stub0nssaNumberofareastransitcapableis0Externalfloodlistlength0AreaBACKBONE 0 AreaBACKBONE 0 AreahasnoauthenticationSPFalgorithmlastexecuted00 01 25 028agoSPFalgorithmexecuted7timesArea1Numberofinterfacesinthisareais1AreahasnoauthenticationSPFalgorithmlastexecuted00 00 54 636agoSPFalgorithmexecuted3times showipprotocols Router OSPF的檢驗(yàn) showiprouteospf process id Router showipospfinterface typenumber Router showipospf Router OSPF的檢驗(yàn) showipospfneighbor typenumber neighbor id detail Router 例 showiprouteospf RouterA showiprouteospf10 0 0 0 8isvariablysubnetted 3subnets 2masksOIA10 2 1 0 24 110 782 via10 64 0 2 00 03 05 FastEthernet0 0RouterA 例 showipospfinterface RouterA 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 floodqueuelength0Next0 x0 0 0 x0 0 Lastfloodscanlengthis1 maximumis4Lastfloodscantimeis0msec maximumis4msecNeighborCountis1 Adjacentneighborcountis1Adjacentwithneighbor10 64 0 2 DesignatedRouter Suppresshellofor0neighbor s 例 Theshowipospfneighbor RouterB showipospfneighborNeighborIDPriStateDeadTimeAddressInterface10 64 0 10FULL DROTHER00 00 3010 64 0 1FastEthernet0 010 2 1 10FULL 00 00 3410 2 1 1Serial0 0 1 RouterB showipospfneighbordetailNeighbor10 64 0 1 interfaceaddress10 64 0 1Inthearea0viainterfaceFastEthernet0 0Neighborpriorityis0 StateisFULL 16statechangesDRis10 64 0 2BDRis0 0 0 0Neighbor10 2 1 1 interfaceaddress10 2 1 1Inthearea1viainterfaceSerial0 0 1Neighborpriorityis0 StateisFULL 6statechangesDRis0 0 0 0BDRis0 0 0 0 Dijkstra算法 Dijkstra算法是路由表計(jì)算的依據(jù) 通過Dijkstra算法可以得到有關(guān)網(wǎng)絡(luò)節(jié)點(diǎn)的最短路徑樹 然后由最短路徑優(yōu)先樹得到路由表 SPF算法有時(shí)也被稱為Dijkstra算法 這是因?yàn)樽疃搪窂絻?yōu)先算法SPF是Dijkstra發(fā)明的 Dijkstra算法 SPF算法將每一個(gè)路由器作為根 ROOT 來計(jì)算其到每一個(gè)目