OSPF綜合實(shí)驗(yàn)大全

.OSPF綜合實(shí)驗(yàn)大全OSPF實(shí)驗(yàn)1：基本的OSPF配置實(shí)驗(yàn)級(jí)別：Assistant實(shí)驗(yàn)拓?fù)洌簩?shí)驗(yàn)步驟：1.首先在3臺(tái)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)#int loopback 0R1(config-if)#ip add R2(config)#int loopback 0R2(config-if)#ip add R3(config)#int loopback 0R3(config-if)#ip add 路由器的RID是路由器接口的最高的IP地址，當(dāng)有環(huán)回口存在是，路由器將使用環(huán)回口的最高IP地址作為起RID，從而保證RID的穩(wěn)定。3在3臺(tái)路由器上分別啟動(dòng)ospf進(jìn)程，并且宣告直連接口的網(wǎng)絡(luò)。R1(config)#router ospf10R1(config-router)#network 55area 0R1(config-router)#network 55 area 0R1(config-router)#network .0.0.255 area 0ospf的進(jìn)程號(hào)只有本地意義，既在不同路由器上的進(jìn)程號(hào)可以不相同。但是為了日后維護(hù)的方便，一般啟用相同的進(jìn)程號(hào)。ospf使用反向掩碼。Area 0表示骨干區(qū)域，在設(shè)計(jì)ospf網(wǎng)絡(luò)時(shí)，所有的非骨干區(qū)域都需要和骨干區(qū)域直連！R2，R3的配置和R1類似，這里省略。不同的是我們?cè)赗2和R3上不宣告各自的環(huán)回口。*Aug 13 17:58:51.411: %OSPF-5-ADJCHG: Process 10, Nbr on Serial1/0 from LOADING to FULL, Loading Done配置結(jié)束后，我們可以看到鄰居關(guān)系已經(jīng)到達(dá)FULL狀態(tài)。4.在R1上查看路由表，可以看到以下信息：R1#show ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route Gateway of last resort is not set /24 is subnetted, 1 subnets C is directly connected, Loopback0 C/24 is directly connected, Serial1/0 O/24 110/65 via , 00:03:42, Serial1/0 C/24 is directly connected, FastEthernet0/ 我們看到R1學(xué)到了/24這個(gè)網(wǎng)段的路由。后面的數(shù)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show ip ospf neighbor、show ip ospf interface R1#show ip ospf neighborNeighbor IDPriStateDead TimeAddressInterface1FULL/BDR00:00:34FastEthernet0/00FULL/-00:00:32Serial1/0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(wǎng)絡(luò)類型中。Point-to-Point,Point-to-Multipoint(廣播與非廣播)這三種網(wǎng)絡(luò)類型不選取DR與BDR; Broadcast,NBMA選取DR與BDR。R1#show ip ospf interfaceFastEthernet0/0 is up, line protocol is upInternet Address /24, Area 0Process ID 10, Router ID ,Network Type BROADCAST, Cost: 1Transmit Delay is 1 sec, State DR, Priority 1Designated Router (ID) , Interface address Backup Designated router (ID) , Interface address Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5oob-resync timeout 40Hello due in 00:00:03Index 3/3, flood queue length 0Next 0x0(0)/0x0(0)Last flood scan length is 1, maximum is 1Last flood scan time is 0 msec, maximum is 0 msecNeighbor Count is 1, Adjacent neighbor count is 1Adjacent with neighbor (Backup Designated Router)Suppress hello for 0 neighbor(s)Serial1/0 is up, line protocol is upInternet Address /24, Area 0Process ID 10, Router ID ,Network Type POINT_TO_POINT, Cost: 64Transmit Delay is 1 sec, State POINT_TO_POINT,Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5oob-resync timeout 40Hello due in 00:00:02Index 1/1, flood queue length 0Next 0x0(0)/0x0(0)Last flood scan length is 1, maximum is 1Last flood scan time is 4 msec, maximum is 4 msecNeighbor Count is 1, Adjacent neighbor count is 1Adjacent with neighbor Suppress hello for 0 neighbor(s)Loopback0 is up, line protocol is upInternet Address /24, Area 0Process ID 10, Router ID ,Network Type LOOPBACK, Cost: 1Loopback interface is treated as astub Host在這里我們看到環(huán)回口的網(wǎng)絡(luò)網(wǎng)絡(luò)類型是Loopback，這是一種特殊的網(wǎng)絡(luò)類型，只針對(duì)環(huán)回口存在。我們到R2上看看路由表：R2#show ip routeCodes: C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static routeGateway of last resort is not set/32 is subnetted, 1 subnetsO 110/65 via , 00:12:34, Serial1/0/24 is subnetted, 1 subnetsC is directly connected, Loopback0C/24 is directly connected, Serial1/0C/24 is directly connected, Serial1/1O/24 110/65 via , 00:12:34, Serial1/0110/65 via , 00:12:34, Serial1/1R2的路由表顯示來自環(huán)回口的路由，掩碼為/32，既我們所說的“主機(jī)路由”。在實(shí)際應(yīng)用中，環(huán)回口以32位的居多，用作ospf的管理接口。但是如果你想讓環(huán)回口模擬一個(gè)網(wǎng)段，我們可以通過以下配置來消除。R1(config)#int loopback 0R1(config-if)#ip ospf network point-to-point環(huán)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?；氐絉2查看路由表：R2#show ip routeCodes: C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static routeGateway of last resort is not set/24 is subnetted, 1 subnetsO 110/65 via , 00:00:24, Serial1/0/24 is subnetted, 1 subnetsC is directly connected, Loopback0C/24 is directly connected, Serial1/0C/24 is directly connected, Serial1/1O/24 110/65 via , 00:00:24, Serial1/0110/65 via , 00:00:24, Serial1/1我們看到主機(jī)路由沒有了，取而代之的是一個(gè)/24的網(wǎng)段。本文出自 “蓋如鶴的步徒” 博客，請(qǐng)務(wù)必保留此出處/77728/38127OSPF實(shí)驗(yàn)2：DR/BDR的選取實(shí)驗(yàn)級(jí)別：Professional情況一： 我們都知道OSPF選取DR的過程是首先比較優(yōu)先級(jí)，在優(yōu)先級(jí)相同的情況下選擇RID較高的為DR，但是我多次實(shí)驗(yàn)后發(fā)現(xiàn)在很多時(shí)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(guān)OSPF DR選取的介紹時(shí)，發(fā)現(xiàn)了這么一句話：“在一個(gè)多址網(wǎng)絡(luò)上，最先初始化啟動(dòng)的兩臺(tái)具有DR選取資格的路由器將成為DR和BDR路由器?！边@是我總結(jié)了非最高RID而成為DR的實(shí)驗(yàn)，發(fā)現(xiàn)這些路由器都是我在進(jìn)行OSPF配置的時(shí)候首先啟動(dòng)ospf的路由器，那會(huì)不會(huì)是因?yàn)檫@些路由器首先啟動(dòng)了OSPF，然后把自己設(shè)置為DR導(dǎo)致其他路由器啟動(dòng)OSPF后就不再進(jìn)行DR的選取了呢？于是我做了下面的這個(gè)實(shí)驗(yàn)。 實(shí)驗(yàn)的topo很簡(jiǎn)單，我就不畫了，就是兩臺(tái)路由器通過fa0/0口相連接。R1:conf tho R1int lo0ip add int fa0/0ip add no shrouter ospf 10net a 0R2:conf tho R2int lo0ip add int fa0/0ip add no shR1啟動(dòng)ospf進(jìn)程后，我們?cè)赗2上暫時(shí)先不開啟ospf，在R1上發(fā)現(xiàn)了以下信息：R1#sho ip ospf intFastEthernet0/0 is up, line protocol is up Internet Address /24, Area 0 Process ID 10, Router ID , Network Type BROADCAST, Cost: 1 Transmit Delay is 1 sec,State DR, Priority 1 Designated Router (ID) , Interface address No backup designated router on this network Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:01 Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 0, maximum is 0 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 0, Adjacent neighbor count is 0 Suppress hello for 0 neighbor(s) 我們看到R1已經(jīng)把自己設(shè)定為DR了，按照OSPF的規(guī)則，新加入的路由器即使RID比DR高，也不會(huì)替換DR。這就說明了為什么在有些時(shí)候DR并非RID最高的路由器。 當(dāng)然這個(gè)實(shí)驗(yàn)也順便驗(yàn)證了ospf中DR選取結(jié)束后，除非DR路由器出現(xiàn)故障，否則就是有更高優(yōu)先級(jí)或者RID的路由器進(jìn)入OSPF進(jìn)程，也是無法改變DR的。既DR是不可以搶奪的！情況二（本實(shí)驗(yàn)參照了ITAA實(shí)驗(yàn)室Netfish的實(shí)驗(yàn)）： ospf中有一個(gè)Wait Timer計(jì)時(shí)器，在這個(gè)計(jì)時(shí)器所限定的時(shí)間內(nèi)起來的OSPF可以視為同時(shí)起機(jī)。 TCP/IP卷1第292頁對(duì)于這個(gè)時(shí)間間隔是這樣定義的： Wait Timer:在開始選舉DR和BDR之間，路由器等待鄰居路由器的Hello數(shù)據(jù)包通告DR和BDR的時(shí)長(zhǎng)。長(zhǎng)度就是RouterDeadInterval的時(shí)間。 本實(shí)驗(yàn)拓?fù)渑c情況一相同，不同的地方在于當(dāng)我們?cè)赗1上啟動(dòng)OSPF后，迅速（一定要迅速，非常迅速！40s之內(nèi)）在R2上也啟動(dòng)ospf，通過debug信息可以看到以下情況：R1#debug ip ospf adjOSPF adjacency events debugging is onR1#debug ip ospf evOSPF events debugging is on*Aug 14 00:56:19.047: OSPF: Interface FastEthernet0/0 going Up*Aug 14 00:56:19.051: OSPF: Send hello to area 0 on FastEthernet0/0 from *Aug 14 00:56:19.551: OSPF: Build router LSA for area 0, router ID , seq 0x80000001*Aug 14 00:56:19.555: OSPF: Rcv hello from area 0 from FastEthernet0/0 *Aug 14 00:56:19.555: OSPF: End of hello processingR1(config-router)#*Aug 14 00:56:29.051: OSPF: Send hello to area 0 on FastEthernet0/0 from *Aug 14 00:56:29.451: OSPF: Rcv hello from area 0 from FastEthernet0/0 *Aug 14 00:56:29.455: OSPF: 2 Way Communication to on FastEthernet0/0, state 2WAY*Aug 14 00:56:29.455: OSPF: End of hello processingR1(config-router)#*Aug 14 00:56:39.051: OSPF: Send hello to area 0 on FastEthernet0/0 from *Aug 14 00:56:39.427: OSPF: Rcv hello from area 0 from FastEthernet0/0 *Aug 14 00:56:39.427: OSPF: End of hello processingR1(config-router)#*Aug 14 00:56:49.051: OSPF: Send hello to area 0 on FastEthernet0/0 from *Aug 14 00:56:49.447: OSPF: Rcv hello from area 0 from FastEthernet0/0 *Aug 14 00:56:49.447: OSPF: End of hello processingR1(config-router)#*Aug 14 00:56:59.051: OSPF: end of Wait on interface FastEthernet0/0*Aug 14 00:56:59.051: OSPF: DR/BDR election on FastEthernet0/0*Aug 14 00:56:59.051: OSPF: Elect BDR *Aug 14 00:56:59.055: OSPF: Elect DR *Aug 14 00:56:59.055: DR: (Id) BDR: (Id)*Aug 14 00:56:59.055: OSPF: Send DBD to on FastEthernet0/0 seq 0x826 opt 0x52 flag 0x7 len 32*Aug 14 00:56:59.059: OSPF: Send hello to area 0 on FastEthernet0/0 from *Aug 14 00:56:59.459: OSPF: Rcv hello from area 0 from FastEthernet0/0 *Aug 14 00:56:59.463: OSPF: Neighbor change Event on interface FastEthernet0/0*Aug 14 00:56:59.463: OSPF: DR/BDR election on FastEthernet0/0*Aug 14 00:56:59.463: OSPF: Elect BDR *Aug 14 00:56:59.467: OSPF: Elect DR *Aug 14 00:56:59.467: OSPF: Elect BDR *Aug 14 00:56:59.467: OSPF: Elect DR *Aug 14 00:56:59.471: DR: (Id) BDR: (Id)這個(gè)時(shí)候我們發(fā)現(xiàn)兩個(gè)路由器進(jìn)行了DR/BDR的選取，并且結(jié)論和書上介紹的完全一致。從Debug信息的時(shí)間上來看，從啟動(dòng)OSPF進(jìn)程到開始選舉DR和DBR的時(shí)間間隔是40秒，在這個(gè)時(shí)間段內(nèi)，無論R1還是R2并沒有選舉DR和DBR。在RFC2328中對(duì)這個(gè)時(shí)間間隔的定義如下：Wait Timer A single shot timer that causes the interface to exit the Waiting state, and as a consequence select a Designated Router on the network. The length of the timer is RouterDeadInterval seconds.因?yàn)樵趶V播鏈路中的RouterDeadInterval是40秒，所以我們看到的這個(gè)時(shí)間間隔為40秒。結(jié)論： 并不是先啟動(dòng)OSPF進(jìn)程的路由器就是DR，而是有一個(gè)時(shí)間間隔讓路由器來等待其他路由器，在這個(gè)時(shí)間間隔內(nèi)，路由器相互監(jiān)聽Hello包中的DR和DBR字段中的信息，并且服從優(yōu)先級(jí)原則，可以這樣認(rèn)為選舉是公平的。實(shí)際情況： 在實(shí)際的網(wǎng)絡(luò)中，即使是40秒內(nèi)同時(shí)起進(jìn)程的情況也少見；實(shí)際情況下是率先啟用ospf進(jìn)程的路由器就很有可能成為DR，第二個(gè)啟動(dòng)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(shí)際的運(yùn)行效果是：“活”得最久的路由器成為DR（比多長(zhǎng)時(shí)間不重起） .OSPF實(shí)驗(yàn)3：OSPF over NBMA下的五種網(wǎng)絡(luò)類型實(shí)驗(yàn)等級(jí)：Professional實(shí)驗(yàn)拓?fù)洌簩?shí)驗(yàn)基本配置：1.首先將R1配置成為幀中繼交換機(jī)：frame-relay switching!interface Serial1/0no ip addressencapsulation frame-relayclock rate 64000frame-relay lmi-type ansiframe-relay intf-type dceframe-relay route 101 interface Serial1/1 102!interface Serial1/1no ip addressencapsulation frame-relayclock rate 64000frame-relay lmi-type ansiframe-relay intf-type dceframe-relay route 102 interface Serial1/0 1012.R2和R3的基本配置：R2：interface Loopback0ip address !interface Serial1/0ip address encapsulation frame-relayserial restart-delay 0frame-relay map ip 101 broadcastno frame-relay inverse-arp!router ospf 10router-id log-adjacency-changesnetwork 55 area 0network 55 area 0R3：interface Loopback0ip address !interface Serial1/1ip address encapsulation frame-relayserial restart-delay 0frame-relay map ip 102 broadcastno frame-relay inverse-arp!router ospf 10router-id log-adjacency-changesnetwork 55 area 0network 55 area 0Type1-Non_Broadcast（默認(rèn)）我們?cè)赗2上show ip ospf neighbor，發(fā)現(xiàn)沒有鄰居。說明在這種情況下鄰居需要手動(dòng)配置！配置如下：R2：R2(config)#router ospf 10R2(config-router)#neighbor R3：R3(config)#router ospf 10R3(config-router)#neighbor 此時(shí)在R2上查看鄰居：R2#sho ip ospf neiNeighbor IDPriStateDead TimeAddressInterface1FULL/DR00:01:46Serial1/0發(fā)現(xiàn)鄰居已經(jīng)形成并且有DR與BDR的選舉！在R2上查看接口R2#show ip ospf interfaceSerial1/0 is up, line protocol is upInternet Address /24, Area 0Process ID 10, Router ID ,Network Type NON_BROADCAST,Cost: 64Transmit Delay is 1 sec, State BDR, Priority 1Designated Router (ID) , Interface address Backup Designated router (ID) , Interface address Flush timer for old DR LSA due in 00:01:40Timer intervals configured,Hello 30, Dead 120, Wait 120, Retransmit 5在這種網(wǎng)絡(luò)類型中，hello的間隔是30s。打開debug信息，我們可以看到在這種網(wǎng)絡(luò)類型中，OSPF的數(shù)據(jù)包是單播傳送的。R2#*Aug 14 14:52:52.819: OSPF: Send hello toarea 0 on Serial1/0 from R2#*Aug 14 14:52:57.087: OSPF: Rcv hello from area 0 from Serial1/0 *Aug 14 14:52:57.091: OSPF: End of hello processingType2- Broadcast首先去掉剛才手動(dòng)配置的鄰居關(guān)系：R2(config)#router ospf 10R2(config-router)#no neighbor R3(config)#router ospf 10R3(config-router)#no neighbor 將R2和R3接口的網(wǎng)絡(luò)類型改成broadcastR2(config-router)#int s1/0R2(config-if)#ip ospf network broadcastR3(config-router)#int s1/1R3(config-if)#ip ospf network broadcast一會(huì)我們就看到了如下信息R3#*Aug 14 14:59:52.823: %OSPF-5-ADJCHG: Process 10, Nbr on Serial1/1 fromLOADING to FULL, Loading Done這說明了在這種網(wǎng)絡(luò)類型下是不需要手動(dòng)配置鄰居關(guān)系的！R2#show ip ospf neiNeighbor IDPriStateDead TimeAddressInterface1FULL/DR00:00:39Serial1/0有DR與BDR的選舉。R2#sho ip ospf intSerial1/0 is up, line protocol is upInternet Address /24, Area 0Process ID 10, Router ID ,Network Type BROADCAST, Cost: 64Transmit Delay is 1 sec, State BDR, Priority 1Designated Router (ID) , Interface address Backup Designated router (ID) , Interface address Timer intervals configured,Hello 10, Dead 40, Wait 40, Retransmit 5Hello時(shí)間間隔為10s。R2#*Aug 14 15:02:20.443: OSPF: Send hello toarea 0 on Serial1/0 from *Aug 14 15:02:20.959: OSPF: Rcv hello from area 0 from Serial1/0 *Aug 14 15:02:20.963: OSPF: End of hello processing使用這個(gè)組播地址傳送數(shù)據(jù)包。Type3- Point-to-Point將R2，R3接口的網(wǎng)絡(luò)類型改成Point-to-PointR2(config-if)#ip ospf net point-to-pointR3(config-if)#ip ospf net point-to-point很快我們就可以看到如下信息R3(config-if)#*Aug 14 15:06:07.559: %OSPF-5-ADJCHG: Process 10, Nbr on Serial1/1 fromLOADING to FULL, Loading Done說明這種網(wǎng)絡(luò)類型也不需要手動(dòng)指定鄰居R2#sho ip ospf neiNeighbor IDPriStateDead TimeAddressInterface0FULL/-00:00:37Serial1/0沒有DR/BDR的選舉R2#sh ip ospf intSerial1/0 is up, line protocol is upInternet Address /24, Area 0Process ID 10, Router ID , Network Type POINT_TO_POINT, Cost: 64Transmit Delay is 1 sec, State POINT_TO_POINT,Timer intervals configured,Hello 10, Dead 40, Wait 40, Retransmit 5Hello時(shí)間間隔為10sR2#*Aug 14 15:08:25.311: OSPF: Send hello toarea 0 on Serial1/0 from R2#*Aug 14 15:08:30.259: OSPF: Rcv hello from area 0 from Serial1/0 *Aug 14 15:08:30.263: OSPF: End of hello processing同樣也是使用這個(gè)組播地址傳送數(shù)據(jù)。Type4- Point-to-Multipoint將接口改為Point-to-MultipointR2(config-if)#ip ospf network point-to-multipointR3(config-if)#ip ospf network point-to-multipoint*Aug 14 15:10:51.739: %OSPF-5-ADJCHG: Process 10, Nbr on Serial1/1 fromLOADING to FULL, Loading Done同樣也不需要手動(dòng)指定鄰居R2#sho ip ospf neiNeighbor IDPriStateDead TimeAddressInterface0FULL/-00:01:48Serial1/0沒有DR和BDR的選舉R2#sho ip ospf intSerial1/0 is up, line protocol is upInternet Address /24, Area 0Process ID 10, Router ID ,Network Type POINT_TO_MULTIPOINT, Cost: 64Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT,Timer intervals configured,Hello 30, Dead 120, Wait 120, Retransmit 5Hello時(shí)間間隔為30sR2#*Aug 14 15:12:49.759: OSPF: Send hello toarea 0 on Serial1/0 from R2#*Aug 14 15:12:57.443: OSPF: Rcv hello from area 0 from Serial1/0 *Aug 14 15:12:57.447: OSPF: End of hello processing以這個(gè)組播地址發(fā)送數(shù)據(jù)Type5- Point-to-Multipoint（Non_Broadcast）改變接口類型為Point-to-Multipoint(Non_Broadcast)R2(config-if)#ip ospf network point-to-multipoint non-broadcastR3(config-if)#ip ospf network point-to-multipoint non-broadcast這個(gè)時(shí)候鄰居沒有被自動(dòng)發(fā)現(xiàn)。我們?cè)赗2上手動(dòng)指定鄰居R2(config-if)#router ospf 10R2(config-router)#neighbor R2(config-router)#*Aug 14 15:18:38.955: %OSPF-5-ADJCHG: Process 10, Nbr on Serial1/0 from LOADING to FULL, Loading Done鄰居只要在一邊指定即可。說明在這種網(wǎng)絡(luò)類型下鄰居需要手動(dòng)指定。R2#sho ip ospf n