R1 router ospf 1 network 1.1.1.0 0.0.0.255 area 0 network 192.168.12.0 0.0.0.255 area 0 =========================================== R2 R2(config)#int range e0/0 -1 , lo0 R2(config-if-range)#ip ospf 1 area 0 ========================================= R3 R3(config)#int lo0 R3(config-if)#ip ospf 1 area 0 R3(config-if)#int e0/0 R3(config-if)#ip ospf 1 area 0 R3(config-if)#int e0/1 R3(config-if)#ip ospf 1 area 0 ======================================== R4 R4(config)#int range lo0 , e0/0 R4(config-if-range)#ip ospf 1 area 0
检查,在任意路由器上,检查路由学习的状况。
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R2#show ip route ospf 1.0.0.0/32 is subnetted, 1 subnets O 1.1.1.1 [110/11] via 192.168.12.1, 00:02:22, Ethernet0/0 3.0.0.0/32 is subnetted, 1 subnets O 3.3.3.3 [110/11] via 192.168.23.3, 00:01:16, Ethernet0/1 4.0.0.0/32 is subnetted, 1 subnets O 4.4.4.4 [110/21] via 192.168.23.3, 00:00:07, Ethernet0/1 O 192.168.34.0/24 [110/20] via 192.168.23.3, 00:00:07, Ethernet0/1
Neighbor ID Pri State Dead Time Address Interface 3.3.3.3 1 FULL/DR 00:00:37 192.168.23.3 Ethernet0/1 1.1.1.1 1 FULL/BDR 00:00:35 192.168.12.1 Ethernet0/0
Neighbor ID:邻居的Router-ID
Pri:优先级
State:邻居状态/接口的角色
Dead Time:死亡时间,一个40s倒计时的计时器,每次收到ospf的hello消息(10s一次)就会重置
自制系统边界路由器:autonomous system boundary router(简称ASBR)
需要引入OSPF外部的路由条目
将上面的拓扑进行更改
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R2#sh ip route ospf 1.0.0.0/32 is subnetted, 1 subnets O 1.1.1.1 [110/11] via 192.168.12.1, 00:10:49, Ethernet0/0 3.0.0.0/32 is subnetted, 1 subnets O 3.3.3.3 [110/2] via 192.168.23.3, 00:10:54, Ethernet0/1 4.0.0.0/32 is subnetted, 1 subnets O IA 4.4.4.4 [110/12] via 192.168.23.3, 00:09:40, Ethernet0/1 O IA 192.168.34.0/24 [110/11] via 192.168.23.3, 00:10:28, Ethernet0/1
R2#sh ip route ospf 1.0.0.0/32 is subnetted, 1 subnets O 1.1.1.1 [110/11] via 192.168.12.1, 00:02:53, Ethernet0/0 3.0.0.0/32 is subnetted, 1 subnets O 3.3.3.3 [110/2] via 192.168.23.3, 00:00:27, Ethernet0/1 4.0.0.0/32 is subnetted, 1 subnets O IA 4.4.4.4 [110/12] via 192.168.23.3, 00:00:07, Ethernet0/1 O IA 192.168.34.0/24 [110/11] via 192.168.23.3, 00:00:27, Ethernet0/1 ==================================================================== R1#sh ip route 1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 1.1.1.0/24 is directly connected, Loopback0 L 1.1.1.1/32 is directly connected, Loopback0 192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks C 192.168.12.0/24 is directly connected, Ethernet0/0 L 192.168.12.1/32 is directly connected, Ethernet0/0 R1#sh ip ospf nei
Neighbor ID Pri State Dead Time Address Interface 2.2.2.2 0 FULL/ - 00:00:37 192.168.12.2 Ethernet0/0
R2#sh ip protocols Routing Protocol is "ospf 1" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 2.2.2.2 Number of areas in this router is 2. 2 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: Routing on Interfaces Configured Explicitly (Area 1): Loopback0 Ethernet0/1 Routing on Interfaces Configured Explicitly (Area 2): Ethernet0/0 Routing Information Sources: Gateway Distance Last Update 3.3.3.3 110 00:01:47 4.4.4.4 110 00:03:21 1.1.1.1 110 00:04:33 Distance: (default is 110) =================================================== R3#sh ip protocols ---------省略---------- It is an area border router ---------省略----------
R2#sh ip ospf nei Neighbor ID Pri State Dead Time Address Interface 3.3.3.3 0 FULL/ - 00:00:01 192.168.23.3 OSPF_VL0 3.3.3.3 0 FULL/ - 00:00:32 192.168.23.3 Ethernet0/1 1.1.1.1 0 FULL/ - 00:00:35 192.168.12.1 Ethernet0/0 R2#show ip ospf virtual-links Virtual Link OSPF_VL0 to router 3.3.3.3 is up R2#show ip protocols ------省略----------- Router ID 2.2.2.2 It is an area border router ------省略-----------
再次查看R1的路由表
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R1#show ip route ospf 2.0.0.0/32 is subnetted, 1 subnets O IA 2.2.2.2 [110/11] via 192.168.12.2, 00:03:45, Ethernet0/0 3.0.0.0/32 is subnetted, 1 subnets O IA 3.3.3.3 [110/12] via 192.168.12.2, 00:03:45, Ethernet0/0 4.0.0.0/32 is subnetted, 1 subnets O IA 4.4.4.4 [110/22] via 192.168.12.2, 00:02:32, Ethernet0/0 O IA 192.168.23.0/24 [110/11] via 192.168.12.2, 00:03:45, Ethernet0/0 O IA 192.168.34.0/24 [110/21] via 192.168.12.2, 00:02:32, Ethernet0/0
Neighbor ID Pri State Dead Time Address Interface 3.3.3.3 0 FULL/ - 00:00:38 172.16.23.3 Tunnel0 3.3.3.3 0 FULL/ - 00:00:39 192.168.23.3 Ethernet0/1 1.1.1.1 0 FULL/ - 00:00:36 192.168.12.1 Ethernet0/0 R2#show ip protocols Routing Protocol is "ospf 1" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 2.2.2.2 It is an area border router # R2满足了ABR的条件 Number of areas in this router is 3. 3 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: Routing on Interfaces Configured Explicitly (Area 0): # 可以看到area 0的情况 Tunnel0 Routing on Interfaces Configured Explicitly (Area 1): Loopback0 Ethernet0/1 Routing on Interfaces Configured Explicitly (Area 2): Ethernet0/0 Routing Information Sources: Gateway Distance Last Update 3.3.3.3 110 00:00:18 4.4.4.4 110 00:00:18 1.1.1.1 110 00:00:22 Distance: (default is 110)
查看R1的路由表
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R1#sh ip route ospf 2.0.0.0/32 is subnetted, 1 subnets O IA 2.2.2.2 [110/11] via 192.168.12.2, 00:01:04, Ethernet0/0 3.0.0.0/32 is subnetted, 1 subnets O IA 3.3.3.3 [110/12] via 192.168.12.2, 00:01:04, Ethernet0/0 4.0.0.0/32 is subnetted, 1 subnets O IA 4.4.4.4 [110/1021] via 192.168.12.2, 00:01:04, Ethernet0/0 172.16.0.0/24 is subnetted, 1 subnets O IA 172.16.23.0 [110/1010] via 192.168.12.2, 00:01:03, Ethernet0/0 O IA 192.168.23.0/24 [110/11] via 192.168.12.2, 00:01:04, Ethernet0/0 O IA 192.168.34.0/24 [110/1020] via 192.168.12.2, 00:01:04, Ethernet0/0
LS age: 55 Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 2.2.2.2 Advertising Router: 2.2.2.2 LS Seq Number: 80000006 Checksum: 0x7739 Length: 84 Number of Links: 5
Link connected to: a Stub Network (Link ID) Network/subnet number: 2.2.2.2 (Link Data) Network Mask: 255.255.255.255 Number of MTID metrics: 0 TOS 0 Metrics: 1
Link connected to: another Router (point-to-point) (Link ID) Neighboring Router ID: 3.3.3.3 (Link Data) Router Interface address: 192.168.23.2 Number of MTID metrics: 0 TOS 0 Metrics: 10
Link connected to: a Stub Network (Link ID) Network/subnet number: 192.168.23.0 (Link Data) Network Mask: 255.255.255.0 Number of MTID metrics: 0 TOS 0 Metrics: 10
Link connected to: another Router (point-to-point) (Link ID) Neighboring Router ID: 1.1.1.1 (Link Data) Router Interface address: 192.168.12.2 Number of MTID metrics: 0 TOS 0 Metrics: 10
Link connected to: a Stub Network (Link ID) Network/subnet number: 192.168.12.0 (Link Data) Network Mask: 255.255.255.0 Number of MTID metrics: 0 TOS 0 Metrics: 10
Net Link States(type 2)
描述TransNet(包括Broadcast和NBMA网络)网络信息;
由DR生成,描述其在该网络上连接的所有路由器以及网段掩码信息,以及这个MA所属的路由器;
LSA类型2只在本区域Area内洪泛,不允许跨越ABR;
Network LSA ID是DR进行宣告的那个接口的IP地址
Network LSA 中没有COST字段
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R1#show ip ospf database network 192.168.1.3
OSPF Router with ID (1.1.1.1) (Process ID 1)
Net Link States (Area 0)
LS age: 310 Options: (No TOS-capability, DC) LS Type: Network Links Link State ID: 192.168.1.3 (address of Designated Router) Advertising Router: 3.3.3.3 LS Seq Number: 80000002 Checksum: 0x8D16 Length: 36 Network Mask: /24 Attached Router: 3.3.3.3 Attached Router: 1.1.1.1 Attached Router: 2.2.2.2
LS age: 203 Options: (No TOS-capability, DC, Upward) LS Type: AS External Link Link State ID: 0.0.0.0 (External Network Number ) Advertising Router: 1.1.1.1 LS Seq Number: 80000004 Checksum: 0x7553 Length: 36 Network Mask: /0 Metric Type: 1 (Comparable directly to link state metric) MTID: 0 Metric: 100 Forward Address: 0.0.0.0 External Route Tag: 1
LS age: 557 Options: (No TOS-capability, Type 7/5 translation, DC, Upward) LS Type: AS External Link Link State ID: 10.1.0.0 (External Network Number ) Advertising Router: 3.3.3.3 LS Seq Number: 80000001 Checksum: 0x172 Length: 36 Network Mask: /24 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 20 Forward Address: 3.3.3.3 External Route Tag: 0
R1 interface Loopback1 ip address 172.16.1.1 255.255.255.0 interface Loopback2 ip address 172.16.2.1 255.255.255.0 interface Loopback3 ip address 172.16.3.1 255.255.255.0 router ospf 1 redistribute connected subnets
在非骨干区域查看,确认学到了外部的条目
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R3#sh ip route ospf O E2 172.16.1.0 [110/20] via 192.168.13.1, 00:00:54, Ethernet0/0 O E2 172.16.2.0 [110/20] via 192.168.13.1, 00:00:54, Ethernet0/0 O E2 172.16.3.0 [110/20] via 192.168.13.1, 00:00:54, Ethernet0/0
R5#sh ip route ospf O*IA 0.0.0.0/0 [110/11] via 192.168.25.2, 00:00:16, Ethernet0/0 6.0.0.0/32 is subnetted, 1 subnets O 6.6.6.6 [110/21] via 192.168.25.2, 00:00:06, Ethernet0/0 O 192.168.26.0/24 [110/20] via 192.168.25.2, 00:00:06, Ethernet0/0
R3#sh ip route ospf Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets O IA 1.1.1.1 [110/11] via 192.168.13.1, 00:03:12, Ethernet0/0 2.0.0.0/32 is subnetted, 1 subnets O IA 2.2.2.2 [110/21] via 192.168.13.1, 00:03:12, Ethernet0/0 4.0.0.0/32 is subnetted, 1 subnets O 4.4.4.4 [110/21] via 192.168.13.1, 00:02:14, Ethernet0/0 5.0.0.0/32 is subnetted, 1 subnets O IA 5.5.5.5 [110/31] via 192.168.13.1, 00:03:12, Ethernet0/0 6.0.0.0/32 is subnetted, 1 subnets O IA 6.6.6.6 [110/31] via 192.168.13.1, 00:03:12, Ethernet0/0 172.16.0.0/24 is subnetted, 3 subnets O N2 172.16.1.0 [110/20] via 192.168.13.1, 00:03:12, Ethernet0/0 O N2 172.16.2.0 [110/20] via 192.168.13.1, 00:03:12, Ethernet0/0 O N2 172.16.3.0 [110/20] via 192.168.13.1, 00:03:12, Ethernet0/0 # 这边能学到是因为R1也是area1的 O IA 192.168.12.0/24 [110/20] via 192.168.13.1, 00:03:12, Ethernet0/0 O 192.168.14.0/24 [110/20] via 192.168.13.1, 00:02:14, Ethernet0/0 O IA 192.168.25.0/24 [110/30] via 192.168.13.1, 00:03:12, Ethernet0/0 O IA 192.168.26.0/24 [110/30] via 192.168.13.1, 00:03:12, Ethernet0/0
在R4上配置3个loopback,地址是172.16.1~3.1/24,并且加入ospf area 2,然后我们观察汇总的特性
检查R3的路由表,可以看到明细路由
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R3#sh ip route ospf 172.16.0.0/32 is subnetted, 3 subnets O 172.16.1.1 [110/11] via 192.168.34.4, 00:01:24, Ethernet0/1 O 172.16.2.1 [110/11] via 192.168.34.4, 00:01:24, Ethernet0/1 O 172.16.3.1 [110/11] via 192.168.34.4, 00:01:24, Ethernet0/1
我们可以尝试在R4上配置汇总
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R4 router ospf 1 area 2 range 172.16.0.0 255.255.0.0
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R3#sh ip route ospf 172.16.0.0/32 is subnetted, 3 subnets O 172.16.1.1 [110/11] via 192.168.34.4, 00:02:41, Ethernet0/1 O 172.16.2.1 [110/11] via 192.168.34.4, 00:02:41, Ethernet0/1 O 172.16.3.1 [110/11] via 192.168.34.4, 00:02:41, Ethernet0/1 # 在同一个区域中,OSPF是不支持汇总的
R3 router ospf 1 area 2 range 172.16.2.1 255.255.255.255 not-advertise
在R2上查看效果
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R2#sh ip route ospf 172.16.0.0/32 is subnetted, 2 subnets O IA 172.16.1.1 [110/21] via 192.168.23.3, 00:09:04, Ethernet0/1 O IA 172.16.3.1 [110/21] via 192.168.23.3, 00:09:04, Ethernet0/1 # 172.16.2.1消失
R3#sh ip route ospf 10.0.0.0/24 is subnetted, 2 subnets O E2 10.1.0.0 [110/20] via 192.168.23.2, 00:02:43, Ethernet0/0 O E2 10.3.0.0 [110/20] via 192.168.23.2, 00:02:43, Ethernet0/0
抑制7类转发地址
在配置好了之后,我们在R2上抑制R1的条目
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router ospf 1 area 1 range 1.1.1.1 255.255.255.255 not-advertise
我们发现R3不仅仅是1.1.1.1无法学习,连10.x.0.0/24也学习不到了
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R3#sh ip route ospf 2.0.0.0/32 is subnetted, 1 subnets O 2.2.2.2 [110/11] via 192.168.23.2, 00:11:48, Ethernet0/0 4.0.0.0/32 is subnetted, 1 subnets O 4.4.4.4 [110/11] via 192.168.34.4, 00:11:48, Ethernet0/1 172.16.0.0/32 is subnetted, 3 subnets O 172.16.1.1 [110/11] via 192.168.34.4, 00:11:48, Ethernet0/1 O 172.16.2.1 [110/11] via 192.168.34.4, 00:11:48, Ethernet0/1 O 172.16.3.1 [110/11] via 192.168.34.4, 00:11:48, Ethernet0/1 O IA 192.168.12.0/24 [110/20] via 192.168.23.2, 00:11:48, Ethernet0/0
虽然R3路由表中没有10开头的地址,但是数据库中竟然还有
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R3#sh ip ospf database ------------省略------------ Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag 10.1.0.0 2.2.2.2 124 0x80000001 0x004F3A 0 10.2.0.0 2.2.2.2 124 0x80000001 0x004345 0 10.3.0.0 2.2.2.2 124 0x80000001 0x003750 0
LS age: 171 Options: (No TOS-capability, DC, Upward) LS Type: AS External Link Link State ID: 10.1.0.0 (External Network Number ) Advertising Router: 2.2.2.2 LS Seq Number: 80000001 Checksum: 0x4F3A Length: 36 Network Mask: /24 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 20 Forward Address: 1.1.1.1 # 这个地址不可达,导致即使有LSA,也是无法使用的 External Route Tag: 0
LS age: 32 Options: (No TOS-capability, DC, Upward) LS Type: AS External Link Link State ID: 10.1.0.0 (External Network Number ) Advertising Router: 2.2.2.2 LS Seq Number: 80000002 Checksum: 0x1B71 Length: 36 Network Mask: /24 Metric Type: 2 (Larger than any link state path) MTID: 0 Metric: 20 Forward Address: 0.0.0.0 External Route Tag: 0 R3#show ip route ospf 10.0.0.0/24 is subnetted, 3 subnets O E2 10.1.0.0 [110/20] via 192.168.23.2, 00:03:15, Ethernet0/0 O E2 10.2.0.0 [110/20] via 192.168.23.2, 00:03:15, Ethernet0/0 O E2 10.3.0.0 [110/20] via 192.168.23.2, 00:03:15, Ethernet0/0 # 发现1.1.1.1没学到,但是外部的条目都可以使用了