OSPF多区域
一，实验要点：
（1），LSA1：路由器LSA（由区域内的路由器发出的，泛洪在内部区域)
（2)，LSA2：网络LSA（由区域内的DR始发的，泛洪在内部区域)
（3)，LSA3：网络汇总LSA(由ABR路由器始发的，通告该区域外部的目的地址）
（4），LSA4：ASBR汇总LSA(由ABR路由器始发的，用于通告ASBR信息，指出谁是ASBR）
（5），LSA5：自治系统外部LSA(由ASBR路由器始发的，用来通告到达OSPF自治系统外部的目的地或者是到OSPF自治系统外部的默认路由的LSA。外部LSA通告将在整个自治系统中进行泛洪）
OSPF 多区域的拓扑结构有如下的优势：
1. 降低SPF 计算频率
2. 减小路由表
3. 降低了通告LSA 的开销
4. 将不稳定限制在特定的区
二，实验拓扑图
R1（loopback0）：1.1.1.1/32 R2（loopback0）：2.2.2.2/32
R3（loopback0）：3.3.3.3/32 R4（loopback0）：4.4.4.4/32
R5（loopback0）：5.5.5.5/32 R6（loopback0）：6.6.6.6/32
R1配置：
R1#conf t
R1(config)#int f0/0
R1(config-if)#ip add 192.168.1.2 255.255.255.252
R1(config-if)#no shut
R1(config-if)#int f0/1
R1(config-if)#ip add 10.1.1.1 255.255.255.252
R1(config-if)#no shut
R1(config-if)#int loo 0
R1(config-if)#ip add 1.1.1.1 255.255.255.255
R1(config-if)#no shut
R1(config-if)#ex
R1(config)#router ospf 110
R1(config-router)#router-id 1.1.1.1
R1(config-router)#network 1.1.1.1 0.0.0.0 a 1
R1(config-router)#network 10.1.1.0 0.0.0.3 a 1
R2配置：
R2#conf t
R2(config)#int f0/0
R2(config-if)#ip add 10.1.1.2 255.255.255.252
R2(config-if)#no shut
R2(config-if)#int f0/1
R2(config-if)#ip add 20.2.2.1 255.255.255.252
R2(config-if)#no shut
R2(config-if)#int loo 0
R2(config-if)#ip add 2.2.2.2 255.255.255.255
R2(config-if)#no shut
R2(config-if)#ex
R2(config)#router ospf 110
R2(config-router)#router-id 2.2.2.2
R2(config-router)#network 2.2.2.2 0.0.0.0 a 1
R2(config-router)#network 10.1.1.0 0.0.0.3 a 1
R2(config-router)#network 20.2.2.0 0.0.0.3 a 1
R3配置：
R3#conf t
R3(config)#int f0/0
R3(config-if)#ip add 20.2.2.2 255.255.255.252
R3(config-if)#no shut
R3(config-if)#int f0/1
R3(config-if)#ip add 30.3.3.1 255.255.255.252
R3(config-if)#no shut
R3(config-if)#int loo 0
R3(config-if)#ip add 3.3.3.3 255.255.255.255
R3(config-if)#no shut
R3(config-if)#ex
R3(config)#router ospf 110
R3(config-router)#router-id 3.3.3.3
R3(config-router)#network 3.3.3.3 0.0.0.0 a 0
R3(config-router)#network 20.2.2.0 0.0.0.3 a 1
R3(config-router)#network 30.3.3.0 0.0.0.3 a 0
R4配置：
R4#conf t
R4(config)#int f0/0
R4(config-if)#ip add 30.3.3.2 255.255.255.252
R4(config-if)#no shut
R4(config-if)#int f0/1
R4(config-if)#ip add 40.4.4.1 255.255.255.252
R4(config-if)#no shut
R4(config-if)#int loo 0
R4(config-if)#ip add 4.4.4.4 255.255.255.255
R4(config-if)#no shut
R4(config-if)#ex
R4(config)#router ospf 110
R4(config-router)#router-id 4.4.4.4
R4(config-router)#network 4.4.4.4 0.0.0.0 a 2
R4(config-router)#network 30.3.3.0 0.0.0.3 a 0
R4(config-router)#network 40.4.4.0 0.0.0.3 a 2
R5配置：
R5#conf t
R5(config)#int f0/0
R5(config-if)#ip add 40.4.4.2 255.255.255.252
R5(config-if)#no shut
R5(config-if)#int loo 0
R5(config-if)#ip add 5.5.5.5 255.255.255.255
R5(config-if)#no shut
R5(config-if)#ex
R5(config)#router ospf 110
R5(config-router)#router-id 5.5.5.5
R5(config-router)#network 5.5.5.5 0.0.0.0 a 2
R5(config-router)#network 40.4.4.0 0.0.0.3 a 2
R6配置：
R6#conf t
R6(config)#int f0/0
R6(config-if)#ip add 192.168.1.1 255.255.255.252
R6(config-if)#no shut
R6(config-if)#int loo 0
R6(config-if)#ip add 6.6.6.6 255.255.255.255
R6(config-if)#no shut
R6(config-if)#ex
R6(config)#router rip
R6(config-router)#version 2
R6(config-router)#no auto-summary
R6(config-router)#network 6.6.6.6
R6(config-router)#network 192.168.1.0
R1配置：
R1(config)#router rip
R1(config-router)#version 2
R1(config-router)#no auto-summary
R1(config-router)#network 192.168.1.0
R1(config-router)#network 1.1.1.1
R1(config-router)#network 10.1.1.0
R1(config)#router ospf 110
R1(config-router)#redistribute rip subnets
R1(config)#router rip
R1(config-router)#redistribute ospf 110 metric 2
R6#ping 5.5.5.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 188/216/268 ms
R5#ping 6.6.6.6
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 6.6.6.6, timeout is 2 seconds:
!!!!!
（至此全网互通）
Success rate is 100 percent (5/5), round-trip min/avg/max = 144/183/212 ms
R1#show ip ospf database router //查看内部数据库中列出的所有路由器LSA通告
OSPF Router with ID (1.1.1.1) (Process ID 110)
Router Link States (Area 1)
LS age: 759
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 1.1.1.1
Advertising Router: 1.1.1.1
LS Seq Number: 80000005
Checksum: 0x17D5
Length: 48
AS Boundary Router
Number of Links: 2
Link connected to: a Transit Network
(Link ID) Designated Router address: 10.1.1.1
(Link Data) Router Interface address: 10.1.1.1
Number of TOS metrics: 0
TOS 0 Metrics: 10
Link connected to: a Stub Network
(Link ID) Network/subnet number: 1.1.1.1
(Link Data) Network Mask: 255.255.255.255
Number of TOS metrics: 0
TOS 0 Metrics: 1
LS age: 1413
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: 0x5045
Length: 60
Number of Links: 3
Link connected to: a Transit Network
(Link ID) Designated Router address: 20.2.2.1
(Link Data) Router Interface address: 20.2.2.1
Number of TOS metrics: 0
TOS 0 Metrics: 10
Link connected to: a Transit Network
(Link ID) Designated Router address: 10.1.1.1
(Link Data) Router Interface address: 10.1.1.2
Number of TOS metrics: 0
TOS 0 Metrics: 10
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 TOS metrics: 0
TOS 0 Metrics: 1
Routing Bit Set on this LSA
LS age: 1521
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 3.3.3.3
Advertising Router: 3.3.3.3
LS Seq Number: 80000003
Checksum: 0x8C4F
Length: 36
Area Border Router
Number of Links: 1
Link connected to: a Transit Network
(Link ID) Designated Router address: 20.2.2.1
(Link Data) Router Interface address: 20.2.2.2
Number of TOS metrics: 0
TOS 0 Metrics: 10
（泛洪在内部区域，由区域内的路由器发出的：LSA1)
R1#show ip ospf database network //查看内部网络LSA通告的信息
OSPF Router with ID (1.1.1.1) (Process ID 110)
Net Link States (Area 1)
Routing Bit Set on this LSA
LS age: 125
Options: (No TOS-capability, DC)
LS Type: Network Links
Link State ID: 10.1.1.1 (address of Designated Router)
Advertising Router: 1.1.1.1
LS Seq Number: 80000003
Checksum: 0x4ECF
Length: 32
Network Mask: /30
Attached Router: 1.1.1.1
Attached Router: 2.2.2.2
Routing Bit Set on this LSA
LS age: 1791
Options: (No TOS-capability, DC)
LS Type: Network Links
Link State ID: 20.2.2.1 (address of Designated Router)
Advertising Router: 2.2.2.2
LS Seq Number: 80000002
Checksum: 0xEC1A
Length: 32
Network Mask: /30
Attached Router: 2.2.2.2
Attached Router: 3.3.3.3
(每一个多址网络中的指定路由器DR都将产生网络LSA通告,即由区域内的DR发出的）
R1#show ip ospf database summary //显示链接状态数据库中的网络汇总LSA信息
OSPF Router with ID (1.1.1.1) (Process ID 110)
Summary Net Link States (Area 1)
Routing Bit Set on this LSA
LS age: 59
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 3.3.3.3 (summary Network Number)
Advertising Router: 3.3.3.3
LS Seq Number: 80000003
Checksum: 0xAA77
Length: 28
Network Mask: /32
TOS: 0 Metric: 1
Routing Bit Set on this LSA
LS age: 59
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 4.4.4.4 (summary Network Number)
Advertising Router: 3.3.3.3
LS Seq Number: 80000003
Checksum: 0xE033
Length: 28
Network Mask: /32
TOS: 0 Metric: 11
Routing Bit Set on this LSA
LS age: 1839
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 5.5.5.5 (summary Network Number)
Advertising Router: 3.3.3.3
LS Seq Number: 80000002
Checksum: 0x19ED
Length: 28
Network Mask: /32
TOS: 0 Metric: 21
Routing Bit Set on this LSA
LS age: 63
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 30.3.3.0 (summary Network Number)
Advertising Router: 3.3.3.3
LS Seq Number: 80000003
Checksum: 0xB053
Length: 28
Network Mask: /30
TOS: 0 Metric: 10
Routing Bit Set on this LSA
LS age: 64
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 40.4.4.0 (summary Network Number)
Advertising Router: 3.3.3.3
LS Seq Number: 80000003
Checksum: 0x7B72
Length: 28
Network Mask: /30
TOS: 0 Metric: 20
（由ABR路由器始发的，ABR将发送网络汇总LSA到一个区域，用来通告外部的目的地址。一台ABR也可以通过网络汇总LSA向area 0通告与它相连的区域内部的目的地址。在一个区域外部，且仍然在一个OSPF自治系统内部的默认路由，可以通过这种LSA来通告。）
R4#show ip ospf database asbr-summary //查看ASBR汇总LSA的信息
OSPF Router with ID (4.4.4.4) (Process ID 110)
Summary ASB Link States (Area 0)
Routing Bit Set on this LSA
LS age: 152
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(AS Boundary Router)
Link State ID: 1.1.1.1 (AS Boundary Router address)
Advertising Router: 3.3.3.3
LS Seq Number: 80000003
Checksum: 0xB75E
Length: 28
Network Mask: /0
TOS: 0 Metric: 20
Summary ASB Link States (Area 2)
LS age: 8
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(AS Boundary Router)
Link State ID: 1.1.1.1 (AS Boundary Router address)
Advertising Router: 4.4.4.4
LS Seq Number: 80000003
Checksum: 0xFD0A
Length: 28
Network Mask: /0
TOS: 0 Metric: 30
（由ABR路由器始发的，用于通告ASBR信息，指出谁是ASBR。ASBR汇总LSA除了所通告的目的地是一个ASBR路由器而不是一个网络外，其他的网络汇总LSA都是一样）
R1#show ip ospf database external //查看AS外部LSA的信息
OSPF Router with ID (1.1.1.1) (Process ID 110)
Type-5 AS External Link States
LS age: 576
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 6.6.6.6 (External Network Number )
Advertising Router: 1.1.1.1
LS Seq Number: 80000003
Checksum: 0xB0D1
Length: 36
Network Mask: /32
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0
LS age: 576
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 192.168.1.0 (External Network Number )
Advertising Router: 1.1.1.1
LS Seq Number: 80000003
Checksum: 0xF63C
Length: 36
Network Mask: /30
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0
（由ASBR始发的，用来通告到达OSPF自治系统外部的目的地或者是到OSPF自治系统外部的默认路由的LSA。外部LSA通告将在整个自治系统中进行泛洪）