CCNP-15 OSPF试验11（BSCI）
CCNP-15 OSPF试验11
实验拓扑：
实验要求：
R1 R2
起
OSPF
，再分别起若干个连续子网的
Loopback
接口作为测试，然后配置
R2
为
ABR
，
R1
为
ASBR
。
试验目的：掌握
OSPF
区域间汇总和自治系统外汇总的配置方法。
实验配置：
R1
：
R1(config)#int s1/0
R1(config-if)#ip add 199.99.1.1 255.255.255.0
R1(config-if)#clock rate 64000
R1(config-if)#no shu
R1(config-if)#exit
R1(config)#int loop0
R1(config-if)#ip add 1.1.1 .1 255.255.255.0
R1(config-if)#exit
R1(config)#int loop1
R1(config-if)#ip add 172.16.1.1 255.255.255.0
R1(config-if)#exit
R1(config)#int loop2
R1(config-if)#ip add 172.16.2.1 255.255.255.0
R1(config-if)#exit
R1(config)#int loop3
R1(config-if)#ip add 172.16.3.1 255.255.255.0
R1(config-if)#exit
R1(config)#int loop4
R1(config-if)#ip add 172.16.0.1 255.255.255.0
R1(config-if)#exit
R1(config)#router ospf 100
R1(config-router)#router-id 1.1.1 .1
R1(config-router)#network 199.99.1.0 0.0.0 .255 area 0
R2
：
R2(config)#int s1/0
R2(config-if)#ip add 199.99.1.2 255.255.255.0
R2(config-if)#no shu
R2(config-if)#exit
R2(config)#int loop0
R2(config-if)#ip add 2.2.2 .2 255.255.255.0
R2(config-if)#exit
R2(config)#int loop1
R2(config-if)#ip add 172.17.0.1 255.255.255.0
R2(config-if)#ip ospf network point-to-point
R2(config-if)#exit
R2(config)#int loop2
R2(config-if)#ip add 172.17.1.1 255.255.255.0
R2(config-if)#ip ospf network point-to-point
R2(config-if)#exit
R2(config)#int loop3
R2(config-if)#ip add 172.17.2.1 255.255.255.0
R2(config-if)#ip ospf network point-to-point
R2(config-if)#exit
R2(config)#int loop4
R2(config-if)#ip add 172.17.3.1 255.255.255.0
R2(config-if)#ip ospf network point-to-point
R2(config-if)#exit
R2(config)#router ospf 100
R2(config-router)#router-id 2.2.2 .2
R2(config-router)#network 199.99.1.0 0.0.0 .255 area 0
以上为基本配置，下面在
R1
上
show ip ospf neighbor
查看一下
OSPF
邻居关系是否成功建立：
R1#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
2.2.2
.2 0 FULL/ - 00:00:38 199.99.1.2 Serial1/0
OK
，好了，
OSPF
配置成功，下面开始把
R2
配置成为
ABR
：
R2(config)#router ospf 100
R2(config-router)#network 172.17.0.0 0.0.0 .255 area 1
R2(config-router)#network 172.17.1.0 0.0.0 .255 area 1
R2(config-router)#network 172.17.2.0 0.0.0 .255 area 1
R2(config-router)#network 172.17.3.0 0.0.0 .255 area 1
在
R2
上配置了一个区域
1
，并且加入了
4
个连续的网段，配置完成后查看一下
R1
上的路由表：
R1#show ip route
Codes: 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
Gateway of last resort is not set
1.0.0 .0/24 is subnetted, 1 subnets
C 1.1.1 .0 is directly connected, Loopback0
172.17.0.0/24 is subnetted, 4 subnets
O IA 172.17.0.0 [110/65] via 199.99.1.2, 00:00:27, Serial1/0
O IA 172.17.1.0 [110/65] via 199.99.1.2, 00:00:27, Serial1/0
O IA 172.17.2.0 [110/65] via 199.99.1.2, 00:00:17, Serial1/0
O IA 172.17.3.0 [110/65] via 199.99.1.2, 00:00:07, Serial1/0
172.16.0.0/24 is subnetted, 4 subnets
C 172.16.0.0 is directly connected, Loopback4
C 172.16.1.0 is directly connected, Loopback1
C 172.16.2.0 is directly connected, Loopback2
C 172.16.3.0 is directly connected, Loopback3
C 199.99.1.0/24 is directly connected, Serial1/0
再查看一下
LSDB
：
R1#show ip ospf database
OSPF Router with ID ( 1.1.1 .1) (Process ID 100)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1
.1 1.1.1 .1 197 0x80000002 0x 0042F 7 2
2.2.2
.2 2.2.2 .2 69 0x80000004 0x00E051 2
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
172.17.0.0 2.2.2 .2 3605 0x80000003 0x00ADC6
172.17.1.0 2.2.2 .2 3605 0x80000003 0x 00A 2D0
172.17.2.0 2.2.2 .2 3605 0x80000002 0x0099D9
172.17.3.0 2.2.2 .2 3605 0x80000002 0x008EE3
可以发现不管是路由表还是
LSDB
都有点大了，解决这个问题的方法是在
ABR
上配置区域间路由汇总，如下在
R2
上的配置：
R2(config)#router ospf 100
R2(config-router)#area 1 range 172.17.0.0 255.255.252.0
R2(config-router)#end
配置完成后，在
R1
和
R2
上都
clear ip ospf p
一下，然后再在
R1
上查看路由表：
R1#show ip route
Codes: 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
Gateway of last resort is not set
1.0.0 .0/24 is subnetted, 1 subnets
C 1.1.1 .0 is directly connected, Loopback0
172.17.0.0/22 is subnetted, 1 subnets
O IA 172.17.0.0 [110/65] via 199.99.1.2, 00:00:03, Serial1/0
172.16.0.0/24 is subnetted, 4 subnets
C 172.16.0.0 is directly connected, Loopback4
C 172.16.1.0 is directly connected, Loopback1
C 172.16.2.0 is directly connected, Loopback2
C 172.16.3.0 is directly connected, Loopback3
C 199.99.1.0/24 is directly connected, Serial1/0
可以看到从原来的
4
条路由汇聚成了一条
22
位的路由，再看一下
LSDB
：
R1#show ip ospf database
OSPF Router with ID ( 1.1.1 .1) (Process ID 100)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1
.1 1.1.1 .1 206 0x80000002 0x 0042F 7 2
2.2.2
.2 2.2.2 .2 78 0x80000004 0x00E051 2
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
172.17.0.0 2.2.2 .2 15 0x80000001 0x00B 6C 2
发现了吧，三类
LSA
就剩下一条了。大大减小了路由表和
LSDB
的大小。
接下来是把
R1
配置成为
ASBR
，如下：
R1(config)#router rip
R1(config-router)#version 2
R1(config-router)#no auto-summary
R1(config-router)#network 172.16.0.0
R1(config-router)#network 172.16.1.0
R1(config-router)#network 172.16.2.0
R1(config-router)#network 172.16.3.0
R1(config-router)#exit
R1(config)#router ospf 100
R1(config-router)#redistribute rip subnets
R1(config-router)#exit
这样配置后
,R1
就是一台
ASBR
了，下面查看
R2
的路由表和
LSDB
：
R2#show ip route
Codes: 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
Gateway of last resort is not set
2.0.0 .0/24 is subnetted, 1 subnets
C 2.2.2 .0 is directly connected, Loopback0
172.17.0.0/16 is variably subnetted, 5 subnets, 2 masks
C 172.17.1.0/24 is directly connected, Loopback2
C 172.17.0.0/24 is directly connected, Loopback1
O 172.17.0.0/22 is a summary, 00:02:36, Null0
C 172.17.3.0/24 is directly connected, Loopback4
C 172.17.2.0/24 is directly connected, Loopback3
172.16.0.0/24 is subnetted, 4 subnets
O E2 172.16.0.0 [110/20] via 199.99.1.1, 00:00:01, Serial1/0
O E2 172.16.1.0 [110/20] via 199.99.1.1, 00:00:06, Serial1/0
O E2 172.16.2.0 [110/20] via 199.99.1.1, 00:00:06, Serial1/0
O E2 172.16.3.0 [110/20] via 199.99.1.1, 00:00:06, Serial1/0
C 199.99.1.0/24 is directly connected, Serial1/0
学到了
4
条
AS
外部路由。
R2#show ip ospf database
OSPF Router with ID ( 2.2.2 .2) (Process ID 100)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1
.1 1.1.1 .1 111 0x80000003 0x 0046F 0 2
2.2.2
.2 2.2.2 .2 221 0x80000004 0x00E051 2
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
172.17.0.0 2.2.2 .2 158 0x80000001 0x00B 6C 2
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
2.2.2
.2 2.2.2 .2 202 0x80000003 0x00D317 4
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
199.99.1.0 2.2.2 .2 222 0x80000001 0x 00F 6D1
Summary ASB Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
1.1.1
.1 2.2.2 .2 105 0x80000001 0x 00935C
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.0.0 1.1.1 .1 5 0x80000004 0x003E9E 0
172.16.1.0 1.1.1 .1 10 0x80000001 0x 0039A 5 0
172.16.2.0 1.1.1 .1 10 0x80000001 0x002EAF 0
172.16.3.0 1.1.1 .1 10 0x80000001 0x0023B9 0
和在配置区域间汇总前遇到的问题是一样的，就是路由表和
LSDB
的体积都比较大，这里解决问题的方法是采用
AS
外部路由汇总，在
R1
上作如下配置：
R1(config)#router ospf 100
R1(config-router)#summary-address 172.16.0.0 255.255.252.0
R1(config-router)#end
配置完成后，为了快速查看实验效果，同样是在
R1 R2
上
clear ip ospf p
，然后查看
R2
的路由表：
R2#show ip route
Codes: 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
Gateway of last resort is not set
2.0.0 .0/24 is subnetted, 1 subnets
C 2.2.2 .0 is directly connected, Loopback0
172.17.0.0/16 is variably subnetted, 5 subnets, 2 masks
C 172.17.1.0/24 is directly connected, Loopback2
C 172.17.0.0/24 is directly connected, Loopback1
O 172.17.0.0/22 is a summary, 00:00:01, Null0
C 172.17.3.0/24 is directly connected, Loopback4
C 172.17.2.0/24 is directly connected, Loopback3
172.16.0.0/22 is subnetted, 1 subnets
O E2 172.16.0.0 [110/20] via 199.99.1.1, 00:00:01, Serial1/0
C 199.99.1.0/24 is directly connected, Serial1/0
原来的
4
条
24
位掩码的外部路由汇聚成了一条
22
位掩码的外部路由，再查看
LSDB
看看有什么变化：
R2#show ip ospf database
OSPF Router with ID ( 2.2.2 .2) (Process ID 100)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1
.1 1.1.1 .1 130 0x80000003 0x 0046F 0 2
2.2.2
.2 2.2.2 .2 240 0x80000004 0x00E051 2
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
172.17.0.0 2.2.2 .2 176 0x80000001 0x00B 6C 2
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
2.2.2
.2 2.2.2 .2 220 0x80000003 0x00D317 4
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
199.99.1.0 2.2.2 .2 241 0x80000001 0x 00F 6D1
Summary ASB Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
1.1.1
.1 2.2.2 .2 124 0x80000001 0x 00935C
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
172.16.0.0 1.1.1 .1 16 0x80000005 0x002DB1 0
类型
5
的
LSA
，也就是
AS
外部
LSA
就剩下了一条了，比原来大大减小了。
实验总结：了解
OSPF
中为了减小路由表和
LSDB
表的大小，可以采用
OSPF
区域间汇总和自治系统外部路由汇总的方法，并且要掌握这两种汇总方法的配置。