OSPF的NSSA区域

来源：互联网发布：网络直播的意义编辑：程序博客网时间：2024/04/28 19:30

1、 OSPF的NSSA区域

a、不完全存根区域，能学习本区域连接的外部路由，能学习域间路由，不能学习其它区域的外部路由

b、含有ASBR路由器的stub区域

c、配置命令：area 区域号 nssa

思考：一般末节区域的路由器都是性能不是很好的，但是现在又不得不加入外网路由，没有办法，使用了NSSA区域，NSSA说白了就是不那么末节的区域，总而言之，NSSA区域就是拓扑设计的一个补救措施，本应是stub区域的，但是现在又不得以连上一个外部网络，而且是绝对NSSA区域，那么就禁止了3，4类lsa，所以就会自动推一个3类的默认路由，让去往域内的路由都匹配这个默认路由。

R1配置

enconf thostname R1 int loopback 0ip address 1.1.1.1 255.255.255.0no shutdownexit int f0/0ip address 192.168.1.1 255.255.255.0no shutdownexit router ospf 1network 1.1.1.0 0.0.0.255 area 0network 192.168.1.0 0.0.0.255 area 0exitend

R2配置

enconf thostname R2 int loopback 0ip address 2.2.2.2 255.255.255.0no shutdownexit int f0/0ip address 192.168.1.2 255.255.255.0no shutdownexit int f0/1ip address 192.168.2.1 255.255.255.0no shutdownexit router ospf 1network 2.2.2.0 0.0.0.255 area 0network 192.168.1.0 0.0.0.255 area 0network 192.168.2.0 0.0.0.255 area 1area 1 nssaexitend

R3配置

enconf thostname R3 int loopback 0ip address 3.3.3.3 255.255.255.0no shutdownexit int f0/1ip address 192.168.2.2 255.255.255.0no shutdownexit int f0/0ip address 202.168.1.1 255.255.255.0no shutdownexit router ospf 1network 192.168.2.0 0.0.0.255 area 1network 3.3.3.0 0.0.0.255 area 1area 1 nssaredistribute static metric-type 1 subnetsexit ip route 4.4.4.0 255.255.255.0 f0/0 end

R4配置

enconf thostname R4 int f0/0ip address 202.168.1.2 255.255.255.0no shutdownexit int loopback 0ip address 4.4.4.4 255.255.255.0no shutdownexit ip route 0.0.0.0 0.0.0.0 f0/0end

R2#show ip ospf database

OSPF Router with ID (2.2.2.2) (Process ID 1)

Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count

2.2.2.2 2.2.2.2 67 0x80000004 0x00410e 2

1.1.1.1 1.1.1.1 67 0x80000003 0x00500e 2

Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum

192.168.1.2 2.2.2.2 67 0x80000001 0x00741f

Summary Net Link States (Area0)

Link ID ADV Router Age Seq# Checksum

192.168.2.0 2.2.2.2 47 0x80000001 0x008f5b

3.3.3.3 2.2.2.2 47 0x80000003 0x00d274

Summary ASB Link States (Area0)

Link ID ADV Router Age Seq# Checksum

2.2.2.2 2.2.2.2 2 0x8000000e 0x009b90

Router Link States (Area 1)

Link ID ADV Router Age Seq# Checksum Link count

2.2.2.2 2.2.2.2 55 0x80000002 0x005d0c 1

3.3.3.3 3.3.3.3 55 0x80000004 0x00a29d 2

Net Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

192.168.2.2 3.3.3.3 55 0x80000001 0x007f07

Summary Net Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

192.168.1.0 2.2.2.2 47 0x80000001 0x009a51

2.2.2.2 2.2.2.2 47 0x80000002 0x00f854

1.1.1.1 2.2.2.2 47 0x80000003 0x002f20

Type-7 AS External Link States(Area 1)

Link ID ADV Router Age Seq# Checksum Tag

4.4.4.0 3.3.3.3 50 0x80000001 0x000fa0 0

Type-5 AS External Link States

Link ID ADV Router Age Seq# Checksum Tag

4.4.4.0 2.2.2.2 50 0x80000001 0x00dfdf 0

R2#show ip route

Codes: C - connected, S - static, I - IGRP,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 - OSPFexternal type 2, E - EGP

i - IS-IS, 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

1.0.0.0/32 is subnetted, 1 subnets

O 1.1.1.1 [110/2] via 192.168.1.1, 00:01:10, FastEthernet0/0

2.0.0.0/24 is subnetted, 1 subnets

C 2.2.2.0 is directly connected, Loopback0

3.0.0.0/32 is subnetted, 1 subnets

O 3.3.3.3 [110/2] via 192.168.2.2, 00:00:55, FastEthernet0/1

4.0.0.0/24 is subnetted, 1 subnets

O N1 4.4.4.0 [110/21] via 192.168.2.2, 00:00:55, FastEthernet0/1

C 192.168.1.0/24 is directly connected, FastEthernet0/0

C 192.168.2.0/24 is directly connected, FastEthernet0/1

解释：不完全存根区域NSSA外部路由为LSA7因为存根区域不能存在LSA5，发送到主干区域时，边界路由器转换为LSA5发送到各区域（除存根区域）。

R3#show ip ospf database

OSPF Router with ID (3.3.3.3) (Process ID 1)

Router Link States (Area 1)

Link ID ADV Router Age Seq# Checksum Link count

3.3.3.3 3.3.3.3 25 0x80000004 0x00a29d 2

2.2.2.2 2.2.2.2 25 0x80000002 0x005d0c 1

Net Link States (Area 1)

Link ID ADV Router Age Seq# Checksum

192.168.2.2 3.3.3.3 25 0x80000001 0x007f07

Summary Net Link States (Area1)

Link ID ADV Router Age Seq# Checksum

192.168.1.0 2.2.2.2 17 0x80000001 0x009a51

2.2.2.2 2.2.2.2 17 0x80000002 0x00f854

1.1.1.1 2.2.2.2 17 0x80000003 0x002f20

Type-7 AS External LinkStates (Area 1)

Link ID ADV Router Age Seq# Checksum Tag

4.4.4.0 3.3.3.3 20 0x80000001 0x000fa0 0

R3#show ip route

Codes: C - connected, S - static, I - IGRP,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 - OSPFexternal type 2, E - EGP

i - IS-IS, 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

1.0.0.0/32 is subnetted, 1 subnets

O IA 1.1.1.1 [110/3] via 192.168.2.1, 00:01:14, FastEthernet0/1

2.0.0.0/32 is subnetted, 1 subnets

O IA 2.2.2.2 [110/2] via 192.168.2.1, 00:01:14, FastEthernet0/1

3.0.0.0/24 is subnetted, 1 subnets

C 3.3.3.0 is directly connected, Loopback0

4.0.0.0/24 is subnetted, 1 subnets

S 4.4.4.0 is directly connected, FastEthernet0/0

O IA 192.168.1.0/24 [110/2] via192.168.2.1, 00:01:14, FastEthernet0/1

C 192.168.2.0/24 is directly connected, FastEthernet0/1

C 202.168.1.0/24 is directly connected, FastEthernet0/0

解释：OIA域间路由，不完全存根区域能接受域间路由，但不接受其他区域的外部路由（本实验其他区域没有设置外部路由，只有本区域有外部路由）。

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