CCNP-13 OSPF试验9
试验拓扑：
试验要求：
R1 R2 R3
全部起
OSPF
，并且按照拓扑划分区域，把
AREA 1
设置成为
NSSA
区域。
试验目的：掌握
OSPF NSSA
的配置方法，并且知道和理解
NSSA
的作用以及
NSSA
区域中路由器的
LSA
的类型。
实验配置：
R1
：
interface Loopback0
ip address
1.1.1
.1 255.255.255.0
ip ospf network point-to-point
!
interface Loopback1
ip address 172.17.1.1 255.255.255.0
ip ospf network point-to-point
!
interface Loopback2
ip address 172.17.2.1 255.255.255.0
ip ospf network point-to-point
!
interface Loopback3
ip address 100.100.100.100 255.255.255.0
!
interface Serial1/0
ip address 199.99.1.1 255.255.255.0
serial restart-delay 0
!
router ospf 100
router-id
1.1.1
.1
log-adjacency-changes
redistribute rip subnets
network 172.17.1.0
0.0.0
.255 area 0
network 172.17.2.0
0.0.0
.255 area 0
network 199.99.1.0
0.0.0
.255 area 0
!
router rip
version 2
network 100.0.0.0
R2
：
interface Loopback0
ip address
2.2.2
.2 255.255.255.0
ip ospf network point-to-point
!
interface Serial1/0
ip address 199.99.1.2 255.255.255.0
serial restart-delay 0
clock rate 64000
!
interface Serial1/1
ip address 199.99.2.1 255.255.255.0
serial restart-delay 0
clock rate 64000
!
router ospf 100
router-id
2.2.2
.2
log-adjacency-changes
area 1 nssa
network 199.99.1.0
0.0.0
.255 area 0
network 199.99.2.0
0.0.0
.255 area 1
R3
：
interface Loopback0
ip address
3.3.3
.3 255.255.255.0
ip ospf network point-to-point
!
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
!
interface Serial1/0
ip address 199.99.2.2 255.255.255.0
serial restart-delay 0
!
router ospf 100
router-id
3.3.3
.3
log-adjacency-changes
area 1 nssa
redistribute rip subnets
network 199.99.2.0
0.0.0
.255 area 1
!
router rip
version 2
network 172.16.0.0
以上为基本配置，注意用红颜色标记的部分。这样配置完成后就把
AREA 1
配置成为了
NSSA
区域，
NSSA
区域具有
STUB
区域的特性，并且
STUB
区域内部可以有
ASBR
，但是
NSSA
区域内可以有
ASBR
。下面在
R2
上查看一下路由表：
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
C
2.2.2
.0 is directly connected, Loopback0
100.0.0.0/24 is subnetted, 1 subnets
O E2 100.100.100.0 [110/20] via 199.99.1.1, 00:00:08, Serial1/0
172.17.0.0/24 is subnetted, 2 subnets
O 172.17.1.0 [110/65] via 199.99.1.1, 00:00:08, Serial1/0
O 172.17.2.0 [110/65] via 199.99.1.1, 00:00:08, Serial1/0
172.16.0.0/24 is subnetted, 3 subnets
O N2 172.16.1.0 [110/20] via 199.99.2.2, 00:00:08, Serial1/1
O N2 172.16.2.0 [110/20] via 199.99.2.2, 00:00:08, Serial1/1
O N2 172.16.3.0 [110/20] via 199.99.2.2, 00:00:08, Serial1/1
C 199.99.2.0/24 is directly connected, Serial1/1
C 199.99.1.0/24 is directly connected, Serial1/0
发现有三条
O N2
路由，这是
NSSA
独有的特性，他把
5
类
LSA
通过
NSSA
区域的
ASBR
转变为
7
类
LSA
后向区域内洪泛，查看一下
LSDB
：
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
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
199.99.2.0
2.2.2
.2 186 0x80000001 0x00EBDB
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
172.17.1.0
2.2.2
.2 68 0x80000002 0x00E04D
172.17.2.0
2.2.2
.2 68 0x80000002 0x00D557
199.99.1.0
2.2.2
.2 68 0x80000002 0x
009A
27
Type-7 AS External Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0
3.3.3
.3 65 0x80000001 0x00DCC0 0
172.16.2.0
3.3.3
.3 65 0x80000001 0x00D1CA 0
172.16.3.0
3.3.3
.3 65 0x80000001 0x
00C
6D4 0
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
100.100.100.0
1.1.1
.1 18 0x80000001 0x00ABC3 0
172.16.1.0
2.2.2
.2 47 0x80000001 0x
008F
1C
0
172.16.2.0
2.2.2
.2 47 0x80000001 0x008426 0
172.16.3.0
2.2.2
.2 47 0x80000001 0x007930 0
看到
LSDB
中有
7
类的
LSA
出现。
再看一下
R1
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
C
1.1.1
.0 is directly connected, Loopback0
100.0.0.0/24 is subnetted, 1 subnets
C 100.100.100.0 is directly connected, Loopback3
172.17.0.0/24 is subnetted, 2 subnets
C 172.17.1.0 is directly connected, Loopback1
C 172.17.2.0 is directly connected, Loopback2
172.16.0.0/24 is subnetted, 3 subnets
O E2 172.16.1.0 [110/20] via 199.99.1.2, 00:00:33, Serial1/0
O E2 172.16.2.0 [110/20] via 199.99.1.2, 00:00:33, Serial1/0
O E2 172.16.3.0 [110/20] via 199.99.1.2, 00:00:33, Serial1/0
O IA 199.99.2.0/24 [110/128] via 199.99.1.2, 00:00:49, Serial1/0
C 199.99.1.0/24 is directly connected, Serial1/0
同样是这三条路由，但是在
AREA 0
区域内看到的是
O E2
路由，也就是说
NSSA
区域的
ABR
把
7
类
LSA
又转变为
5
类
LSA
后，再向其他区域洪泛。
下面在
R3
上
show ip route
看看路由表：
R3#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
C
3.3.3
.0 is directly connected, Loopback0
172.17.0.0/24 is subnetted, 2 subnets
O IA 172.17.1.0 [110/129] via 199.99.2.1, 00:00:36, Serial1/0
O IA 172.17.2.0 [110/129] via 199.99.2.1, 00:00:36, Serial1/0
172.16.0.0/24 is subnetted, 3 subnets
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 199.99.2.0/24 is directly connected, Serial1/0
O IA 199.99.1.0/24 [110/128] via 199.99.2.1, 00:00:36, Serial1/0
我们发现了
3
条区域间路由，但是并没有到
100.100.100.0/24
的路由，这与
STUB
区域的
ABR
把
5
类
LSA
转变为
3
类
LSA
后洪泛不太一样，在这里，
NSSA
区域的
ABR
默认是不会注入默认路由的，但是可以通过在
NSSA
区域的
ABR
的
OSPF NSSA
配置中添加
default-information-originate no-summary
选项来解决这个问题，下面为添加了
default-information-originate no-summary
后路由表的变化：
R2(config-router)#area 1 nssa default-information-originate
R3#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 199.99.2.1 to network
0.0.0
.0
C
3.3.3
.0 is directly connected, Loopback0
172.17.0.0/24 is subnetted, 2 subnets
O IA 172.17.1.0 [110/129] via 199.99.2.1, 00:00:49, Serial1/0
O IA 172.17.2.0 [110/129] via 199.99.2.1, 00:00:49, Serial1/0
172.16.0.0/24 is subnetted, 3 subnets
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 199.99.2.0/24 is directly connected, Serial1/0
O IA 199.99.1.0/24 [110/128] via 199.99.2.1, 00:00:49, Serial1/0
O*N2
0.0.0
.0/0 [110/1] via 199.99.2.1, 00:00:00, Serial1/0
可以看到最后面有一条
O*N2
的默认路由，下一条地址是
199.99.2.1
，也就是
ABR
的地址。
OK
，这样的话就可以通过默认路由到达
100.100.100.0/24
了。
下面我们来把
AREA 1
配置成为完全
NSSA
区域。与完全
STUB
配置方法相同，只需在路由配置模式中输入：
area 1 nssa default-information-originate no-summary
这样，
AREA 1
区玉酒杯配置成为了一个完全
NSSA
区域。完全
NSSA
区域也具有完全
STUB
区域的特性，查看一下
R3
的路由表就可以知道了：
R3#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 199.99.2.1 to network
0.0.0
.0
C
3.3.3
.0 is directly connected, Loopback0
172.16.0.0/24 is subnetted, 3 subnets
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 199.99.2.0/24 is directly connected, Serial1/0
O*I
A 0.0.0
.0/0 [110/65] via 199.99.2.1, 00:00:36, Serial1/0
可以发现就剩下一条默认路由了，查看一下
LSDB
：
R3#show ip ospf database
OSPF Router with ID (
3.3.3
.3) (Process ID 100)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
Type-7 AS External Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Tag
172.16.1.0
3.3.3
.3 45 0x80000001 0x00DCC0 0
172.16.2.0
3.3.3
.3 45 0x80000001 0x00D1CA 0
172.16.3.0
3.3.3
.3 45 0x80000001 0x
00C
6D4 0
可以看到
R3
的
LSDB
里面就剩下一条
实验总结：掌握
OSPF NSSA
和完全
NSSA
的配置方法，并且知道和理解
NSSA
的主要特性：不会自动注入默认路由，
NSSA
区域中的
ASBR
将
5
类
LSA
转变为
7
类
LSA
向区域内洪泛，然后
NSSA
区域的
ABR
又将
7
类
LSA
转变为
5
类
LSA
向其他区域洪泛。
本文转自loveme2351CTO博客，原文链接：
http://blog.51cto.com/loveme23/46899
，如需转载请自行联系原作者
