CCNP-11 OSPF试验7(BSCI)-优快云博客

CCNP-11 OSPF试验7

实验拓扑：

试验要求：R1 R2 R3 R4按照拓扑上连好，R1 R2 R4起OSPF，R3起RIPv2，首先把AREA 1设置为普通区域，并且配置R1重分布RIPv2路由到OSPF，观察R4上的LSDB的类型，然后再把AREA 1配置成为STUB区域，观察R4的LSDB有什么变化。

试验目的：掌握OSPF STUB的配置方法，并且能够分析LSDB的变化。

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 s1/1

R1(config-if)#ip add 199.99.2.1 255.255.255.0

R1(config-if)#clock rate 64000

R1(config-if)#no shu

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 s1/1

R2(config-if)#ip add 199.99.3.1 255.255.255.0

R2(config-if)#clock rate 64000

R2(config-if)#no shu

R2(config-if)#exit

R3：

R3(config)#int s1/0

R3(config-if)#ip add 199.99.2.2 255.255.255.0

R3(config-if)#no shu

R3(config-if)#exit

R4：

R4(config)#int s1/0

R4(config-if)#ip add 199.99.3.2 255.255.255.0

R4(config-if)#no shu

R4(config-if)#exit

OK，基本的链路层配置完毕，然后用ping测试连通性，这里略，然后在R1 R2 R4上配置OSPF，R3 R1上配置RIP，并在R1上重分布RIP路由到OSPF中，都起loopback口：

R1(config)#int loop0

R1(config-if)#ip add 1.1.1.1 255.255.255.0

R1(config-if)#ip ospf network point-to-point

R1(config-if)#exit

R1(config)#router ospf 100

R1(config-router)#network 199.99.1.0 0.0.0.255 area 0

R1(config-router)#exit

R1(config)#router rip

R1(config-router)#version 2

R1(config-router)#network 199.99.2.0

R1(config-router)#no auto-summary

R1(config-router)#exit

R1(config)#router ospf 100

R1(config-router)#redistribute rip subnets

R1(config-router)#exit

R2(config)#int loop0

R2(config-if)#ip add 2.2.2.2 255.255.255.0

R2(config-if)#ip ospf network point-to-point

R2(config-if)#exit

R2(config)#router ospf 100

R2(config-router)#network 199.99.1.0 0.0.0.255 area 0

R2(config-router)#network 199.99.3.0 0.0.0.255 area 1

R3(config)#int loop 0

R3(config-if)#ip add 3.3.3.3 255.255.255.0

R3(config-if)#no shu

R3(config-if)#exit

R3(config)#router rip

R3(config-router)#version 2

R3(config-router)#network 199.99.2.0

R3(config-router)#network 3.3.3.0

R3(config-router)#no auto-summary

R3(config-router)#end

R4(config)#int loop0

R4(config-if)#ip add 4.4.4.4 255.255.255.0

R4(config-if)#ip ospf network point-to-point

R4(config-if)#exit

R4(config)#router ospf 100

R4(config-router)#network 199.99.3.0 0.0.0.255 area 1

好了，注意每台路由器和不同路由协议所通告的网段，下面我们在R1 R2 R4上show ip route查看一下路由表：

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

3.0.0.0/24 is subnetted, 1 subnets

R 3.3.3.0 [120/1] via 199.99.2.2, 00:00:07, Serial1/1

O IA 199.99.3.0/24 [110/128] via 199.99.1.2, 00:01:12, Serial1/0

C 199.99.2.0/24 is directly connected, Serial1/1

C 199.99.1.0/24 is directly connected, Serial1/0

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

3.0.0.0/24 is subnetted, 1 subnets

O E2 3.3.3.0 [110/20] via 199.99.1.1, 00:00:02, Serial1/0

C 199.99.3.0/24 is directly connected, Serial1/1

O E2 199.99.2.0/24 [110/20] via 199.99.1.1, 00:00:08, Serial1/0

C 199.99.1.0/24 is directly connected, Serial1/0

R4#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

3.0.0.0/24 is subnetted, 1 subnets

O E2 3.3.3.0 [110/20] via 199.99.3.1, 00:00:08, Serial1/0

4.0.0.0/24 is subnetted, 1 subnets

C 4.4.4.0 is directly connected, Loopback0

C 199.99.3.0/24 is directly connected, Serial1/0

O E2 199.99.2.0/24 [110/20] via 199.99.3.1, 00:00:09, Serial1/0

O IA 199.99.1.0/24 [110/128] via 199.99.3.1, 00:00:35, Serial1/0

我们在R2和R4的路由表里发现了O E2和O IA路由，O E2表示从自治系统外部学到的路由，O IA表示从相同自治系统中不同区域学到的路由，下面我们show ip ospf database查看一下LSDB表：

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 6 0x80000003 0x0046F0 2

2.2.2.2 2.2.2.2 29 0x80000004 0x00E051 2

Summary Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum

199.99.3.0 2.2.2.2 28 0x80000001 0x00E0E5

Type-5 AS External Link States

Link ID ADV Router Age Seq# Checksum Tag

199.99.2.0 1.1.1.1 5 0x80000001 0x00E589 0

以上为R1的LSDB，发现里面有LSA TYPE-1 and 3 and 5，由此我们可以知道R1为ASBR。

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 15 0x80000003 0x0046F0 2

2.2.2.2 2.2.2.2 36 0x80000004 0x00E051 2

Summary Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum

199.99.3.0 2.2.2.2 35 0x80000001 0x00E0E5

Router Link States (Area 1)

Link ID ADV Router Age Seq# Checksum Link count

2.2.2.2 2.2.2.2 40 0x80000001 0x0083A2 2

4.4.4.4 4.4.4.4 40 0x80000002 0x00AF6D 2

Summary Net Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

199.99.1.0 2.2.2.2 40 0x80000001 0x00F6D1

Summary ASB Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

1.1.1.1 2.2.2.2 9 0x80000001 0x00935C

Type-5 AS External Link States

Link ID ADV Router Age Seq# Checksum Tag

3.3.3.0 1.1.1.1 4 0x80000001 0x005D36 0

199.99.2.0 1.1.1.1 15 0x80000001 0x00E589 0

以上为R2的LSDB，发现它包含了两个区域的LSDB，说明它是一台ABR，同样我们可以看到LSA TYPE-1 and 3 and 5。

R4#show ip ospf database

OSPF Router with ID (4.4.4.4) (Process ID 100)

Router Link States (Area 1)

Link ID ADV Router Age Seq# Checksum Link count

2.2.2.2 2.2.2.2 47 0x80000001 0x0083A2 2

4.4.4.4 4.4.4.4 46 0x80000002 0x00AF6D 2

Summary Net Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

199.99.1.0 2.2.2.2 47 0x80000001 0x00F6D1

Summary ASB Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

1.1.1.1 2.2.2.2 16 0x80000001 0x00935C

Type-5 AS External Link States

Link ID ADV Router Age Seq# Checksum Tag

3.3.3.0 1.1.1.1 12 0x80000001 0x005D36 0

199.99.2.0 1.1.1.1 22 0x80000001 0x00E589 0

以上为R4的LSDB，包含了LSA TYPE-1 and 3 and 4 and 5。

接下来我们把AREA 1配置成为STUB区域，看看LSDB有什么变化：

R2(config)#router ospf 100

R2(config-router)#area 1 stub

R4(config)#router ospf 100

R4(config-router)#area 1 stub

注意：area xx stub这条命令要在STUB区域内的每台OSPF路由器上配置，否则无法成功建立邻居关系！然后我们在R4上clear ip route *，再show ip route查看，看看是否有什么变化？

R4#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 199.99.3.1 to network 0.0.0.0

4.0.0.0/24 is subnetted, 1 subnets

C 4.4.4.0 is directly connected, Loopback0

C 199.99.3.0/24 is directly connected, Serial1/0

O IA 199.99.1.0/24 [110/128] via 199.99.3.1, 00:00:07, Serial1/0

O*IA 0.0.0.0/0 [110/65] via 199.99.3.1, 00:00:07, Serial1/0

R4#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

3.0.0.0/24 is subnetted, 1 subnets

O E2 3.3.3.0 [110/20] via 199.99.3.1, 00:00:08, Serial1/0

4.0.0.0/24 is subnetted, 1 subnets

C 4.4.4.0 is directly connected, Loopback0

C 199.99.3.0/24 is directly connected, Serial1/0

O E2 199.99.2.0/24 [110/20] via 199.99.3.1, 00:00:09, Serial1/0

O IA 199.99.1.0/24 [110/128] via 199.99.3.1, 00:00:35, Serial1/0

发现了吗？原来的O E2路由没有了，变成了O*IA路由了，下一跳地址为ABR的接口地址，show ip ospf database查看一下LSDB的变化：

R4#show ip ospf database

OSPF Router with ID (4.4.4.4) (Process ID 100)

Router Link States (Area 1)

Link ID ADV Router Age Seq# Checksum Link count

2.2.2.2 2.2.2.2 22 0x80000003 0x009D88 2

4.4.4.4 4.4.4.4 20 0x80000004 0x00C953 2

Summary Net Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

0.0.0.0 2.2.2.2 27 0x80000001 0x0075C0

199.99.1.0 2.2.2.2 27 0x80000002 0x0013B6

R4#show ip ospf database

OSPF Router with ID (4.4.4.4) (Process ID 100)

Router Link States (Area 1)

Link ID ADV Router Age Seq# Checksum Link count

2.2.2.2 2.2.2.2 47 0x80000001 0x0083A2 2

4.4.4.4 4.4.4.4 46 0x80000002 0x00AF6D 2

Summary Net Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

199.99.1.0 2.2.2.2 47 0x80000001 0x00F6D1

Summary ASB Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

1.1.1.1 2.2.2.2 16 0x80000001 0x00935C

Type-5 AS External Link States

Link ID ADV Router Age Seq# Checksum Tag

3.3.3.0 1.1.1.1 12 0x80000001 0x005D36 0

199.99.2.0 1.1.1.1 22 0x80000001 0x00E589 0

原来的LSA TYPE-4 and 5的LSA没有了，多了一条三类的默认路由，由此我们可以判断出STUB区域中的ABR将外部来的5类LSA转变为默认3类LSA后，再向区域内泛洪。这样配置后LSDB的体积明显小多了。

实验总结：掌握OSPF的特殊区域STUB区域的配置方法，理解STUB区域的作用，理解STUB区域的ABR将阻止外部传来的4和5类LSA洪泛到STUB区域内，并且将5类LSA转变为一条默认的3类LSA后，再向STUB区域内洪泛。

本文转自loveme2351CTO博客，原文链接：http://blog.51cto.com/loveme23/46604 ，如需转载请自行联系原作者