...wd......wd......wd...OSPF綜合實驗大全OSPF實驗1：基本的OSPF配置實驗級別：Assistant實驗拓撲：實驗步驟：1.首先在3臺路由器上配置物理接口，并且使用ping命令確保物理鏈路的暢通。2.在路由器上配置loopback接口：R1(config)#intloopback0R1(config-if)#ipadd1.1.1.1255.255.255.0R2(config)#intloopback0R2(config-if)#ipadd2.2.2.2255.255.255.0R3(config)#intloopback0R3(config-if)#ipadd3.3.3.3255.255.255.0路由器的RID是路由器接口的最高的IP地址，當有環回口存在是，路由器將使用環回口的最高IP地址作為起RID，從而保證RID的穩定。3．在3臺路由器上分別啟動ospf進程，并且宣告直連接口的網絡。R1(config)#routerospf10R1(config-router)#network192.168.1.00.0.0.255area0R1(config-router)#network1.1.1.00.0.0.255area0R1(config-router)#network192.168.3.0.0.0.255area0ospf的進程號只有本地意義，既在不同路由器上的進程號可以不一樣。但是為了日后維護的方便，一般啟用一樣的進程號。ospf使用反向掩碼。Area0表示骨干區域，在設計ospf網絡時，所有的非骨干區域都需要和骨干區域直連！R2，R3的配置和R1類似，這里省略。不同的是我們在R2和R3上不宣告各自的環回口。*Aug1317:58:51.411:%OSPF-5-ADJCHG:Process10,Nbr2.2.2.2onSerial1/0fromLOADINGtoFULL,LoadingDone配置完畢后，我們可以看到鄰居關系已經到達FULL狀態。

4.在R1上查看路由表，可以看到以下信息：R1#showiprouteCodes:C-connected,S-static,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2i-IS-IS,su-IS-ISsummary,L1-IS-ISlevel-1,L2-IS-ISlevel-2ia-IS-ISinterarea,*-candidatedefault,U-per-userstaticrouteo-ODR,P-periodicdownloadedstaticrouteGatewayoflastresortisnotset1.0.0.0/24issubnetted,1subnetsC1.1.1.0isdirectlyconnected,Loopback0C192.168.1.0/24isdirectlyconnected,Serial1/0O192.168.2.0/24[110/65]via192.168.1.2,00:03:42,Serial1/0C192.168.3.0/24isdirectlyconnected,FastEthernet0/我們看到R1學到了192.168.2.0/24這個網段的路由。后面的數字[110/65]，分別表示OSPF的管理距離〔AD〕和路由的Metric值OSPF的Metric值是由cost值逐跳累加的。Cost=100Mb/帶寬值。5.在R1上showipospfneighbor、showipospfinterfaceR1#showipospfneighborNeighborIDPriStateDeadTimeAddressInterface3.3.3.31FULL/BDR00:00:34192.168.3.3FastEthernet0/02.2.2.20FULL/-00:00:32192.168.1.2Serial1/0我們看到R1和R3選取了DR和BDR，而R1和R2沒有選取。在ospf的五種網絡類型中。Point-to-Point,Point-to-Multipoint(播送與非播送)這三種網絡類型不選取DR與BDR;Broadcast,NBMA選取DR與BDR。R1#showipospfinterfaceFastEthernet0/0isup,lineprotocolisupInternetAddress192.168.3.1/24,Area0ProcessID10,RouterID1.1.1.1,NetworkTypeBROADCAST,Cost:1TransmitDelayis1sec,StateDR,Priority1DesignatedRouter(ID)1.1.1.1,Interfaceaddress192.168.3.1BackupDesignatedrouter(ID)3.3.3.3,Interfaceaddress192.168.3.3Timerintervalsconfigured,Hello10,Dead40,Wait40,Retransmit5oob-resynctimeout40Helloduein00:00:03Index3/3,floodqueuelength0Next0x0(0)/0x0(0)Lastfloodscanlengthis1,maximumis1Lastfloodscantimeis0msec,maximumis0msecNeighborCountis1,Adjacentneighborcountis1Adjacentwithneighbor3.3.3.3(BackupDesignatedRouter)Suppresshellofor0neighbor(s)Serial1/0isup,lineprotocolisupInternetAddress192.168.1.1/24,Area0ProcessID10,RouterID1.1.1.1,NetworkTypePOINT_TO_POINT,Cost:64TransmitDelayis1sec,StatePOINT_TO_POINT,Timerintervalsconfigured,Hello10,Dead40,Wait40,Retransmit5oob-resynctimeout40Helloduein00:00:02Index1/1,floodqueuelength0Next0x0(0)/0x0(0)Lastfloodscanlengthis1,maximumis1Lastfloodscantimeis4msec,maximumis4msecNeighborCountis1,Adjacentneighborcountis1Adjacentwithneighbor2.2.2.2Suppresshellofor0neighbor(s)Loopback0isup,lineprotocolisupInternetAddress1.1.1.1/24,Area0ProcessID10,RouterID1.1.1.1,NetworkTypeLOOPBACK,Cost:1LoopbackinterfaceistreatedasastubHost在這里我們看到環回口的網絡網絡類型是Loopback，這是一種特殊的網絡類型，只針對環回口存在。我們到R2上看看路由表：R2#showiprouteCodes:C-connected,S-static,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2i-IS-IS,su-IS-ISsummary,L1-IS-ISlevel-1,L2-IS-ISlevel-2ia-IS-ISinterarea,*-candidatedefault,U-per-userstaticrouteo-ODR,P-periodicdownloadedstaticrouteGatewayoflastresortisnotset1.0.0.0/32issubnetted,1subnetsO1.1.1.1[110/65]via192.168.1.1,00:12:34,Serial1/02.0.0.0/24issubnetted,1subnetsC2.2.2.0isdirectlyconnected,Loopback0C192.168.1.0/24isdirectlyconnected,Serial1/0C192.168.2.0/24isdirectlyconnected,Serial1/1O192.168.3.0/24[110/65]via192.168.1.1,00:12:34,Serial1/0[110/65]via192.168.2.3,00:12:34,Serial1/1R2的路由表顯示來自環回口的路由，掩碼為/32，既我們所說的“主機路由〞。在實際應用中，環回口以32位的居多，用作ospf的管理接口。但是如果你想讓環回口模擬一個網段，我們可以通過以下配置來消除。R1(config)#intloopback0R1(config-if)#ipospfnetworkpoint-to-point環回口只能配置成point-to-point這種類型，不可以配置成其它的類型。回到R2查看路由表：R2#showiprouteCodes:C-connected,S-static,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2i-IS-IS,su-IS-ISsummary,L1-IS-ISlevel-1,L2-IS-ISlevel-2ia-IS-ISinterarea,*-candidatedefault,U-per-userstaticrouteo-ODR,P-periodicdownloadedstaticrouteGatewayoflastresortisnotset1.0.0.0/24issubnetted,1subnetsO1.1.1.0[110/65]via192.168.1.1,00:00:24,Serial1/02.0.0.0/24issubnetted,1subnetsC2.2.2.0isdirectlyconnected,Loopback0C192.168.1.0/24isdirectlyconnected,Serial1/0C192.168.2.0/24isdirectlyconnected,Serial1/1O192.168.3.0/24[110/65]via192.168.1.1,00:00:24,Serial1/0[110/65]via192.168.2.3,00:00:24,Serial1/1我們看到主機路由沒有了，取而代之的是一個/24的網段。本文出自“蓋如鶴的步徒〞博客，請務必保存此出處://gairuhe.blog.51cto/77728/38127OSPF實驗2：DR/BDR的選取實驗級別：Professional情況一：我們都知道OSPF選取DR的過程是首先比較優先級，在優先級一樣的情況下選擇RID較高的為DR，但是我屢次實驗后發現在很多時候DR并非RID最高的路由器，這是什么原因呢在翻閱了卷一有關OSPFDR選取的介紹時，發現了這么一句話：“在一個多址網絡上，最先初始化啟動的兩臺具有DR選取資格的路由器將成為DR和BDR路由器。〞這是我總結了非最高RID而成為DR的實驗，發現這些路由器都是我在進展OSPF配置的時候首先啟動ospf的路由器，那會不會是因為這些路由器首先啟動了OSPF，然后把自己設置為DR導致其他路由器啟動OSPF后就不再進展DR的選取了呢于是我做了下面的這個實驗。實驗的topo很簡單，我就不畫了，就是兩臺路由器通過fa0/0口相連接。

R1:

conft

hoR1

intlo0

ipadd1.1.1.1255.255.255.0

intfa0/0

ipadd172.1.1.1255.255.255.0

nosh

routerospf10

net172.1.1.10.0.0.0a0R2:

conft

hoR2

intlo0

ipadd2.2.2.2255.255.255.0

intfa0/0

ipadd172.1.1.2255.255.255.0

noshR1啟動ospf進程后，我們在R2上暫時先不開啟ospf，在R1上發現了以下信息：R1#shoipospfint

FastEthernet0/0isup,lineprotocolisupInternetAddress172.1.1.1/24,Area0ProcessID10,RouterID1.1.1.1,NetworkTypeBROADCAST,Cost:1

TransmitDelayis1sec,StateDR,Priority1DesignatedRouter(ID)1.1.1.1,Interfaceaddress172.1.1.1

Nobackupdesignatedrouteronthisnetwork

Timerintervalsconfigured,Hello10,Dead40,Wait40,Retransmit5

oob-resynctimeout40

Helloduein00:00:01

Index1/1,floodqueuelength0

Next0x0(0)/0x0(0)

Lastfloodscanlengthis0,maximumis0

Lastfloodscantimeis0msec,maximumis0msec

NeighborCountis0,Adjacentneighborcountis0Suppresshellofor0neighbor(s)我們看到R1已經把自己設定為DR了，按照OSPF的規則，新參加的路由器即使RID比DR高，也不會替換DR。這就說明了為什么在有些時候DR并非RID最高的路由器。當然這個實驗也順便驗證了ospf中DR選取完畢后，除非DR路由器出現故障，否則就是有更高優先級或者RID的路由器進入OSPF進程，也是無法改變DR的。既DR是不可以搶奪的！情況二〔本實驗參照了ITAA實驗室Netfish的實驗〕：ospf中有一個WaitTimer計時器，在這個計時器所限定的時間內起來的OSPF可以視為同時起機。TCP/IP卷1第292頁對于這個時間間隔是這樣定義的：WaitTimer:在開場選舉DR和BDR之間，路由器等待鄰居路由器的Hello數據包通告DR和BDR的時長。長度就是RouterDeadInterval的時間。本實驗拓撲與情況一一樣，不同的地方在于當我們在R1上啟動OSPF后，迅速〔一定要迅速，非常迅速！40s之內〕在R2上也啟動ospf，通過debug信息可以看到以下情況：R1#debugipospfadj

OSPFadjacencyeventsdebuggingison

R1#debugipospfev

OSPFeventsdebuggingison*Aug1400:56:19.047:OSPF:InterfaceFastEthernet0/0goingUp

*Aug1400:56:19.051:OSPF:Sendhelloto224.0.0.5area0onFastEthernet0/0from172.1.1.1

*Aug1400:56:19.551:OSPF:BuildrouterLSAforarea0,routerID1.1.1.1,seq0x80000001

*Aug1400:56:19.555:OSPF:Rcvhellofrom2.2.2.2area0fromFastEthernet0/0172.1.1.2

*Aug1400:56:19.555:OSPF:Endofhelloprocessing

R1(config-router)#

*Aug1400:56:29.051:OSPF:Sendhelloto224.0.0.5area0onFastEthernet0/0from172.1.1.1

*Aug1400:56:29.451:OSPF:Rcvhellofrom2.2.2.2area0fromFastEthernet0/0172.1.1.2

*Aug1400:56:29.455:OSPF:2WayCommunicationto2.2.2.2onFastEthernet0/0,state2WAY

*Aug1400:56:29.455:OSPF:Endofhelloprocessing

R1(config-router)#

*Aug1400:56:39.051:OSPF:Sendhelloto224.0.0.5area0onFastEthernet0/0from172.1.1.1

*Aug1400:56:39.427:OSPF:Rcvhellofrom2.2.2.2area0fromFastEthernet0/0172.1.1.2

*Aug1400:56:39.427:OSPF:Endofhelloprocessing

R1(config-router)#

*Aug1400:56:49.051:OSPF:Sendhelloto224.0.0.5area0onFastEthernet0/0from172.1.1.1

*Aug1400:56:49.447:OSPF:Rcvhellofrom2.2.2.2area0fromFastEthernet0/0172.1.1.2

*Aug1400:56:49.447:OSPF:Endofhelloprocessing

R1(config-router)#

*Aug1400:56:59.051:OSPF:endofWaitoninterfaceFastEthernet0/0*Aug1400:56:59.051:OSPF:DR/BDRelectiononFastEthernet0/0

*Aug1400:56:59.051:OSPF:ElectBDR2.2.2.2

*Aug1400:56:59.055:OSPF:ElectDR2.2.2.2

*Aug1400:56:59.055:DR:2.2.2.2(Id)BDR:2.2.2.2(Id)

*Aug1400:56:59.055:OSPF:SendDBDto2.2.2.2onFastEthernet0/0seq0x826opt0x52flag0x7len32

*Aug1400:56:59.059:OSPF:Sendhelloto224.0.0.5area0onFastEthernet0/0from172.1.1.1

*Aug1400:56:59.459:OSPF:Rcvhellofrom2.2.2.2area0fromFastEthernet0/0172.1.1.2

*Aug1400:56:59.463:OSPF:NeighborchangeEventoninterfaceFastEthernet0/0

*Aug1400:56:59.463:OSPF:DR/BDRelectiononFastEthernet0/0

*Aug1400:56:59.463:OSPF:ElectBDR1.1.1.1

*Aug1400:56:59.467:OSPF:ElectDR2.2.2.2

*Aug1400:56:59.467:OSPF:ElectBDR1.1.1.1

*Aug1400:56:59.467:OSPF:ElectDR2.2.2.2

*Aug1400:56:59.471:DR:2.2.2.2(Id)BDR:1.1.1.1(Id)這個時候我們發現兩個路由器進展了DR/BDR的選取，并且結論和書上介紹的完全一致。從Debug信息的時間上來看，從啟動OSPF進程到開場選舉DR和DBR的時間間隔是40秒，在這個時間段內，無論R1還是R2并沒有選舉DR和DBR。在RFC2328中對這個時間間隔的定義如下：

WaitTimer

Asingleshottimerthatcausestheinterfacetoexitthe

Waitingstate,andasaconsequenceselectaDesignatedRouter

onthenetwork.ThelengthofthetimerisRouterDeadInterval

seconds.因為在播送鏈路中的RouterDeadInterval是40秒，所以我們看到的這個時間間隔為40秒。結論：并不是先啟動OSPF進程的路由器就是DR，而是有一個時間間隔讓路由器來等待其他路由器，在這個時間間隔內，路由器相互監聽Hello包中的DR和DBR字段中的信息，并且服從優先級原則，可以這樣認為——選舉是公平的。實際情況：在實際的網絡中，即使是40秒內同時起進程的情況也少見；實際情況下是率先啟用ospf進程的路由器就很有可能成為DR，第二個啟動的就很有可能成為BDR，考慮到路由器故障或者重啟等情況，實際的運行效果是：“活〞得最久的路由器成為DR〔比多長時間不重起〕.OSPF實驗3：OSPFoverNBMA下的五種網絡類型實驗等級：Professional實驗拓撲：實驗基本配置：1.首先將R1配置成為幀中繼交換機：frame-relayswitching!interfaceSerial1/0noipaddressencapsulationframe-relayclockrate64000frame-relaylmi-typeansiframe-relayintf-typedceframe-relayroute101interfaceSerial1/1102!interfaceSerial1/1noipaddressencapsulationframe-relayclockrate64000frame-relaylmi-typeansiframe-relayintf-typedceframe-relayroute102interfaceSerial1/01012.R2和R3的基本配置：R2：interfaceLoopback0ipaddress2.2.2.2255.255.255.0!interfaceSerial1/0ipaddress12.1.1.2255.255.255.0encapsulationframe-relayserialrestart-delay0frame-relaymapip12.1.1.3101broadcastnoframe-relayinverse-arp!routerospf10router-id2.2.2.2log-adjacency-changesnetwork2.2.2.00.0.0.255area0network12.1.1.00.0.0.255area0R3：interfaceLoopback0ipaddress3.3.3.3255.255.255.0!interfaceSerial1/1ipaddress12.1.1.3255.255.255.0encapsulationframe-relayserialrestart-delay0frame-relaymapip12.1.1.2102broadcastnoframe-relayinverse-arp!routerospf10router-id3.3.3.3log-adjacency-changesnetwork3.3.3.00.0.0.255area0network12.1.1.00.0.0.255area0Type1----Non_Broadcast〔默認〕我們在R2上showipospfneighbor，發現沒有鄰居。說明在這種情況下鄰居需要手動配置！配置如下：R2：R2(config)#routerospf10R2(config-router)#neighbor12.1.1.3R3：R3(config)#routerospf10R3(config-router)#neighbor12.1.1.2此時在R2上查看鄰居：R2#shoipospfneiNeighborIDPriStateDeadTimeAddressInterface3.3.3.31FULL/DR00:01:4612.1.1.3Serial1/0發現鄰居已經形成并且有DR與BDR的選舉！在R2上查看接口R2#showipospfinterfaceSerial1/0isup,lineprotocolisupInternetAddress12.1.1.2/24,Area0ProcessID10,RouterID2.2.2.2,NetworkTypeNON_BROADCAST,Cost:64TransmitDelayis1sec,StateBDR,Priority1DesignatedRouter(ID)3.3.3.3,Interfaceaddress12.1.1.3BackupDesignatedrouter(ID)2.2.2.2,Interfaceaddress12.1.1.2FlushtimerforoldDRLSAduein00:01:40Timerintervalsconfigured,Hello30,Dead120,Wait120,Retransmit5在這種網絡類型中，hello的間隔是30s。翻開debug信息，我們可以看到在這種網絡類型中，OSPF的數據包是單播傳送的。R2#*Aug1414:52:52.819:OSPF:Sendhelloto12.1.1.3area0onSerial1/0from12.1.1.2R2#*Aug1414:52:57.087:OSPF:Rcvhellofrom3.3.3.3area0fromSerial1/012.1.1.3*Aug1414:52:57.091:OSPF:EndofhelloprocessingType2----Broadcast首先去掉剛剛手動配置的鄰居關系：R2(config)#routerospf10R2(config-router)#noneighbor12.1.1.3R3(config)#routerospf10R3(config-router)#noneighbor12.1.1.2將R2和R3接口的網絡類型改成broadcastR2(config-router)#ints1/0R2(config-if)#ipospfnetworkbroadcastR3(config-router)#ints1/1R3(config-if)#ipospfnetworkbroadcast一會我們就看到了如下信息R3#*Aug1414:59:52.823:%OSPF-5-ADJCHG:Process10,Nbr2.2.2.2onSerial1/1fromLOADINGtoFULL,LoadingDone這說明了在這種網絡類型下是不需要手動配置鄰居關系的！R2#showipospfneiNeighborIDPriStateDeadTimeAddressInterface3.3.3.31FULL/DR00:00:3912.1.1.3Serial1/0有DR與BDR的選舉。R2#shoipospfintSerial1/0isup,lineprotocolisupInternetAddress12.1.1.2/24,Area0ProcessID10,RouterID2.2.2.2,NetworkTypeBROADCAST,Cost:64TransmitDelayis1sec,StateBDR,Priority1DesignatedRouter(ID)3.3.3.3,Interfaceaddress12.1.1.3BackupDesignatedrouter(ID)2.2.2.2,Interfaceaddress12.1.1.2Timerintervalsconfigured,Hello10,Dead40,Wait40,Retransmit5Hello時間間隔為10s。R2#*Aug1415:02:20.443:OSPF:Sendhelloto224.0.0.5area0onSerial1/0from12.1.1.2*Aug1415:02:20.959:OSPF:Rcvhellofrom3.3.3.3area0fromSerial1/012.1.1.3*Aug1415:02:20.963:OSPF:Endofhelloprocessing使用224.0.0.5這個組播地址傳送數據包。Type3----Point-to-Point將R2，R3接口的網絡類型改成Point-to-PointR2(config-if)#ipospfnetpoint-to-pointR3(config-if)#ipospfnetpoint-to-point很快我們就可以看到如下信息R3(config-if)#*Aug1415:06:07.559:%OSPF-5-ADJCHG:Process10,Nbr2.2.2.2onSerial1/1fromLOADINGtoFULL,LoadingDone說明這種網絡類型也不需要手動指定鄰居R2#shoipospfneiNeighborIDPriStateDeadTimeAddressInterface3.3.3.30FULL/-00:00:3712.1.1.3Serial1/0沒有DR/BDR的選舉R2#shipospfintSerial1/0isup,lineprotocolisupInternetAddress12.1.1.2/24,Area0ProcessID10,RouterID2.2.2.2,NetworkTypePOINT_TO_POINT,Cost:64TransmitDelayis1sec,StatePOINT_TO_POINT,Timerintervalsconfigured,Hello10,Dead40,Wait40,Retransmit5Hello時間間隔為10sR2#*Aug1415:08:25.311:OSPF:Sendhelloto224.0.0.5area0onSerial1/0from12.1.1.2R2#*Aug1415:08:30.259:OSPF:Rcvhellofrom3.3.3.3area0fromSerial1/012.1.1.3*Aug1415:08:30.263:OSPF:Endofhelloprocessing同樣也是使用224.0.0.5這個組播地址傳送數據。Type4----Point-to-Multipoint將接口改為Point-to-MultipointR2(config-if)#ipospfnetworkpoint-to-multipointR3(config-if)#ipospfnetworkpoint-to-multipoint*Aug1415:10:51.739:%OSPF-5-ADJCHG:Process10,Nbr2.2.2.2onSerial1/1fromLOADINGtoFULL,LoadingDone同樣也不需要手動指定鄰居R2#shoipospfneiNeighborIDPriStateDeadTimeAddressInterface3.3.3.30FULL/-00:01:4812.1.1.3Serial1/0沒有DR和BDR的選舉R2#shoipospfintSerial1/0isup,lineprotocolisupInternetAddress12.1.1.2/24,Area0ProcessID10,RouterID2.2.2.2,NetworkTypePOINT_TO_MULTIPOINT,Cost:64TransmitDelayis1sec,StatePOINT_TO_MULTIPOINT,Timerintervalsconfigured,Hello30,Dead120,Wait120,Retransmit5Hello時間間隔為30sR2#*Aug1415:12:49.759:OSPF:Sendhelloto224.0.0.5area0onSerial1/0from12.1.1.2R2#*Aug1415:12:57.443:OSPF:Rcvhellofrom3.3.3.3area0fromSerial1/012.1.1.3*Aug1415:12:57.447:OSPF:Endofhelloprocessing以224.0.0.5這個組播地址發送數據Type5----Point-to-Multipoint〔Non_Broadcast〕改變接口類型為Point-to-Multipoint(Non_Broadcast)R2(config-if)#ipospfnetworkpoint-to-multipointnon-broadcastR3(config-if)#ipospfnetworkpoint-to-multipointnon-broadcast這個時候鄰居沒有被自動發現。我們在R2上手動指定鄰居R2(config-if)#routerospf10R2(config-router)#neighbor12.1.1.3R2(config-router)#*Aug1415:18:38.955:%OSPF-5-ADJCHG:Process10,Nbr3.3.3.3onSerial1/0fromLOADINGtoFULL,LoadingDone鄰居只要在一邊指定即可。說明在這種網絡類型下鄰居需要手動指定。R2#shoipospfneiNeighborIDPriStateDeadTimeAddressInterface3.3.3.30FULL/-00:01:5712.1.1.3Serial1/0同樣沒有DR和BDR的選取R2#shoipospfintSerial1/0isup,lineprotocolisupInternetAddress12.1.1.2/24,Area0ProcessID10,RouterID2.2.2.2,NetworkTypePOINT_TO_MULTIPOINT,Cost:64TransmitDelayis1sec,StatePOINT_TO_MULTIPOINT,Timerintervalsconfigured,Hello30,Dead120,Wait120,Retransmit5Hello時間間隔為30sR2#*Aug1415:21:03.099:OSPF:Sendhelloto12.1.1.3area0onSerial1/0from12.1.1.2*Aug1415:21:03.295:OSPF:Rcvhellofrom3.3.3.3area0fromSerial1/012.1.1.3*Aug1415:21:03.299:OSPF:Endofhelloprocessing使用單播傳送OSPF數據。總結：在NBMA網絡下5種網絡類型具體情況如下表所示：網絡類型鄰居自動發現有無DR選舉Hello間隔傳輸方式Non_broadcast否有30s單播Broadcast是有10s組播Point-to-Point是無10s組播Point-to-Multipoint是無30s組播Point-to-Multipoint(非播送)否無30s單播本文出自“蓋如鶴的步徒〞博客，請務必保存此出處://gairuhe.blog.51cto/77728/38241OSPF實驗4：虛鏈路實驗等級：Professional實驗拓撲：實驗分析：上面這個網絡的設計在OSPF中是比較失敗的，因為OSPF建議所有的非骨干區域都和骨干區域直連。上面這個網絡的設計將會導致Area2的數據和Area0無法通信。為了解決這個問題，一種方法可以在R3和R1上增加一條物理鏈路。還有一種過渡的方法就是使用虛鏈路。實驗基本配置：R1：interfaceLoopback0ipaddress1.1.1.1255.255.255.0ipospfnetworkpoint-to-point!interfaceSerial1/0ipaddress10.1.1.1255.255.255.0serialrestart-delay0!routerospf10router-id1.1.1.1log-adjacency-changesnetwork10.1.1.00.0.0.255area0R2：interfaceLoopback0ipaddress2.2.2.2255.255.255.0!interfaceSerial1/0ipaddress10.1.1.2255.255.255.0serialrestart-delay0!interfaceSerial1/1ipaddress11.1.1.1255.255.255.0serialrestart-delay0!routerospf10router-id2.2.2.2log-adjacency-changesnetwork10.1.1.00.0.0.255area0network11.1.1.00.0.0.255area1R3：interfaceLoopback0ipaddress3.3.3.3255.255.255.0!interfaceSerial1/0ipaddress11.1.1.2255.255.255.0serialrestart-delay0!routerospf10router-id3.3.3.3log-adjacency-changesnetwork3.3.3.00.0.0.255area2network11.1.1.00.0.0.255area1我們在R1上查看路由表，發現沒有R3的Loopback接口路由：R1#shoiprouCodes:C-connected,S-static,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2i-IS-IS,su-IS-ISsummary,L1-IS-ISlevel-1,L2-IS-ISlevel-2ia-IS-ISinterarea,*-candidatedefault,U-per-userstaticrouteo-ODR,P-periodicdownloadedstaticrouteGatewayoflastresortisnotset1.0.0.0/24issubnetted,1subnetsC1.1.1.0isdirectlyconnected,Loopback010.0.0.0/24issubnetted,1subnetsC10.1.1.0isdirectlyconnected,Serial1/011.0.0.0/24issubnetted,1subnetsOIA11.1.1.0[110/128]via10.1.1.2,00:04:50,Serial1/0為了讓R1學習到R3的路由，我們配置虛鏈路。虛鏈路的配置：虛鏈路必須配置在ABR上，在這個網絡中ABR是R2和R3。虛鏈路的配置使用的命令是areatransit-area-idvirtual-linkrouter-id。我們現在在R2和R3上進展配置。R2(config)#routerospf10R2(config-router)#area1virtual-link3.3.3.3R3(config)#routerospf10R3(config-router)#area1virtual-link2.2.2.2等虛鏈路起來后，我們查看其狀態：R2#shoipospfvirtual-linksVirtualLinkOSPF_VL0torouter3.3.3.3isupRunasdemandcircuitDoNotAgeLSAallowed.Transitarea1,viainterfaceSerial1/1,Costofusing64TransmitDelayis1sec,StatePOINT_TO_POINT,Timerintervalsconfigured,Hello10,Dead40,Wait40,Retransmit5Helloduein00:00:05AdjacencyStateFULL(Hellosuppressed)Index2/3,retransmissionqueuelength0,numberofretransmission1First0x0(0)/0x0(0)Next0x0(0)/0x0(0)Lastretransmissionscanlengthis1,maximumis1Lastretransmissionscantimeis0msec,maximumis0msec在上面的信息中我們可以看到。虛鏈路在邏輯上是等同于一條物理的按需鏈路，既只有在兩端路由器的配置有變動的時候才進展更新，并且使用的是不老化〔DoNotAge〕LSA，既虛鏈路是無須Hello包控制的。R1#shoiprouCodes:C-connected,S-static,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2i-IS-IS,su-IS-ISsummary,L1-IS-ISlevel-1,L2-IS-ISlevel-2ia-IS-ISinterarea,*-candidatedefault,U-per-userstaticrouteo-ODR,P-periodicdownloadedstaticrouteGatewayoflastresortisnotset1.0.0.0/24issubnetted,1subnetsC1.1.1.0isdirectlyconnected,Loopback03.0.0.0/32issubnetted,1subnetsOIA3.3.3.3[110/129]via10.1.1.2,00:03:02,Serial1/010.0.0.0/24issubnetted,1subnetsC10.1.1.0isdirectlyconnected,Serial1/011.0.0.0/24issubnetted,1subnetsOIA11.1.1.0[110/128]via10.1.1.2,00:03:02,Serial1/0這時看到R1已經學習到了R3環回口的路由。Metric值為129，虛鏈路的Metric等同于所經過的全部鏈路開銷之和，在這個網絡中，Metric=1〔Loopback〕+64+64=129。在R1上查看OSPF數據庫：R1#showipospfdatabaseOSPFRouterwithID(1.1.1.1)(ProcessID10)RouterLinkStates(Area0)LinkIDADVRouterAgeSeq#ChecksumLinkcount1.1.1.11.1.1.17970x800000020x00B9C022.2.2.22.2.2.23690x800000040x00DD2933.3.3.33.3.3.36(DNA)0x800000020x008B351SummaryNetLinkStates(Area0)LinkIDADVRouterAgeSeq#Checksum3.3.3.33.3.3.312(DNA)0x800000010x00AE7511.1.1.02.2.2.27890x800000010x0029BE11.1.1.03.3.3.312(DNA)0x800000010x000BD8這里的〔DNA〕就是DoNotAge。總結：虛鏈路被看成網絡設計失敗的一種補救手段，它不僅可以讓沒有和骨干區域直連的非骨干區域在邏輯上建立一條鏈路，還可以連接兩個別離的骨干區域。但是由于虛鏈路的配置會造成日后維護和排錯的困難。所以在進展網絡設計的時候，不能將虛鏈路考慮進去。本文出自“蓋如鶴的步徒〞博客，請務必保存此出處://gairuhe.blog.51cto/77728/38402OSPF實驗7：OSPF特殊區域實驗級別：Professional實驗拓撲：實驗說明：R2為ABR和ASBR，R3在NSSA實驗時會成為ASBR。在做這個實驗之前，首先我們要了解一下OSPFLSA的類型。見下表：類型代碼類型名稱描述1路由器LSA每臺路由器都會產生，在區域內泛洪2網絡LSADR產生，在區域內泛洪3網絡匯總LSAABR始發，在整個OSPF域中泛洪4ASBR匯總LSAABR始發，在整個OSPF域中泛洪5AS外部LSAASBR始發，在整個OSPF域中泛洪6組成員LSA標識OSPF組播中的組成員，不做討論7NSSA外部LSAASBR始發，8外部屬性LSA沒有實現9OpaqueLSA〔本地鏈路范圍〕

用于MPLS流量工程，不做討論10OpaqueLSA〔本地區域范圍〕11OpaqueLSA〔AS范圍〕在一個OSPF的普通區域，會存在LSA1,LSA2,LSA3,LSA4,LSA5這些LSA，并且數量很多。我們可以通過OSPF的特殊區域的配置讓某些區域減少LSA數目和路由表的條目。基本配置：R1:interfaceLoopback0ipaddress1.1.1.1255.255.255.0ipospfnetworkpoint-to-point!interfaceSerial1/0ipaddress10.1.1.1255.255.255.0serialrestart-delay0!routerospf10router-id1.1.1.1log-adjacency-changesnetwork1.1.1.00.0.0.255area0network10.1.1.00.0.0.255area0R2:interfaceLoopback0ipaddress2.2.2.2255.255.255.0!interfaceSerial1/0ipaddress10.1.1.2255.255.255.0serialrestart-delay0!interfaceSerial1/1ipaddress11.1.1.1255.255.255.0serialrestart-delay0!routerospf10router-id2.2.2.2log-adjacency-changesredistributeconnectedsubnetsnetwork10.1.1.00.0.0.255area0network11.1.1.00.0.0.255area1R3:interfaceLoopback0ipaddress3.3.3.3255.255.255.0!interfaceFastEthernet0/0noipaddressshutdownduplexhalf!interfaceSerial1/0ipaddress11.1.1.2255.255.255.0serialrestart-delay0!routerospf10router-id3.3.3.3log-adjacency-changesnetwork11.1.1.00.0.0.255area1在R1和R3上查看路由表：R1#shoiprouCodes:C-connected,S-static,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2i-IS-IS,su-IS-ISsummary,L1-IS-ISlevel-1,L2-IS-ISlevel-2ia-IS-ISinterarea,*-candidatedefault,U-per-userstaticrouteo-ODR,P-periodicdownloadedstaticrouteGatewayoflastresortisnotset1.0.0.0/24issubnetted,1subnetsC1.1.1.0isdirectlyconnected,Loopback02.0.0.0/24issubnetted,1subnetsOE22.2.2.0[110/20]via10.1.1.2,00:03:00,Serial1/010.0.0.0/24issubnetted,1subnetsC10.1.1.0isdirectlyconnected,Serial1/011.0.0.0/24issubnetted,1subnetsOIA11.1.1.0[110/128]via10.1.1.2,00:03:00,Serial1/0R3#shoiprouCodes:C-connected,S-static,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2i-IS-IS,su-IS-ISsummary,L1-IS-ISlevel-1,L2-IS-ISlevel-2ia-IS-ISinterarea,*-candidatedefault,U-per-userstaticrouteo-ODR,P-periodicdownloadedstaticrouteGatewayoflastresortisnotset1.0.0.0/24issubnetted,1subnetsOIA1.1.1.0[110/129]via11.1.1.1,00:02:51,Serial1/02.0.0.0/24issubnetted,1subnetsOE22.2.2.0[110/20]via11.1.1.1,00:02:51,Serial1/03.0.0.0/24issubnetted,1subnetsC3.3.3.0isdirectlyconnected,Loopback010.0.0.0/24issubnetted,1subnetsOIA10.1.1.0[110/128]via11.1.1.1,00:02:51,Serial1/011.0.0.0/24issubnetted,1subnetsC11.1.1.0isdirectlyconnected,Serial1/0OE2的路由是通過LSA5傳播，OIA的路由是通過LSA3來傳播。1.StubArea我們觀察拓撲，發現Area1不管去外部的那個目的網絡，都必須通過ABRR2進展轉發。在這種情況下，Area1可以配置成StubArea。StubArea可以阻止LSA5，，并且處在區域邊界的ABR將會通過LSA3發送一個默認路由給StubArea。處在StubArea內的所有路由器都必須配置成為StubArea。首先查看R3的OSPF數據庫R3#shoipospfdaOSPFRouterwithID(3.3.3.3)(ProcessID10)RouterLinkStates(Area1)LinkIDADVRouterAgeSeq#ChecksumLinkcount2.2.2.22.2.2.290x800000070x00309C13.3.3.33.3.3.310x800000060x00451E2SummaryNetLinkStates(Area1)LinkIDADVRouterAgeSeq#Checksum0.0.0.02.2.2.21990x800000010x0075C01.1.1.02.2.2.290x800000030x00B13D10.1.1.02.2.2.290x800000030x0032B4Type-5ASExternalLinkStatesLinkIDADVRouterAgeSeq#ChecksumTag2.2.2.02.2.2.28420x800000010x00632F0通過以下配置可以將Area1配置成為StubArea。R2(config)#routerospf10R2(config-router)#area1stubR3(config)#routerospf10R3(config-router)#area1stub在R3上查看路由表：R3#shoiprouCodes:C-connected,S-static,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2i-IS-IS,su-IS-ISsummary,L1-IS-ISlevel-1,L2-IS-ISlevel-2ia-IS-ISinterarea,*-candidatedefault,U-per-userstaticrouteo-ODR,P-periodicdownloadedstaticrouteGatewayoflastresortis11.1.1.1tonetwork0.0.0.01.0.0.0/24issubnetted,1subnetsOIA1.1.1.0[110/129]via11.1.1.1,00:00:16,Serial1/03.0.0.0/24issubnetted,1subnetsC3.3.3.0isdirectlyconnected,Loopback010.0.0.0/24issubnetted,1subnetsOIA10.1.1.0[110/128]via11.1.1.1,00:00:16,Serial1/011.0.0.0/24issubnetted,1subnetsC11.1.1.0isdirectlyconnected,Serial1/0O*IA0.0.0.0/0[110/65]via11.1.1.1,00:00:16,Serial1/0發現原來的OE2路由沒有了，取代了1條默認路由O*IA0.0.0.0/0[110/65]〔通過LSA3通告〕在看R3的OSPF數據庫R3#shoipospfdaOSPFRouterwithID(3.3.3.3)(ProcessID10)RouterLinkStates(Area1)LinkIDADVRouterAgeSeq#ChecksumLinkcount2.2.2.22.2.2.270x8000000A0x00BEA623.3.3.33.3.3.360x800000080x005F042SummaryNetLinkStates(Area1)LinkIDADVRouterAgeSeq#Checksum0.0.0.02.2.2.2120x800000010x0075C01.1.1.02.2.2.2120x800000040x00CD2210.1.1.02.2.2.2120x800000040x004E9此時已經沒有Type-5ASExternalLinkStates的LSA了。2.TotallyStubArea對于本實驗的Area1來說，其實域間路由OIA也是不需要的。我們可以將Area1配置成為TotallyStubArea，從而來阻止LSA3和LSA4在這個區域的傳播,出了通告缺省路由的那一條類型3的LSA。TotallyStubArea的配置也很簡單，只需要在ABR上將其配置成為totallystubarea，并且這個區域的所有路由器配置成為stubarea就可以了。在這個實驗中，我們在上面已經將R3配置成stubarea，只要在R2上配置area1成為TotallyStubArea即可。R2(config-router)#area1stubno-summary在R3上查看路由表和數據庫R3#shoiprouCodes:C-connected,S-static,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA