ASBR汇总LSA（ASBR Summary LSA）
产生：ABR产生
内容：通告的是ASBR这个路由器，到达这个ASBR的代价
泛洪范围：整个OSPF
查看命令：show ip ospf database asbr-summary
图片解析：
可以看到地址是主机地址,掩码是0.0.0.0 说明到一台路由器的路由
这个地方也是距离矢量哈
命令查看：
R4#sh ip ospf database asbr-summary
OSPF Router with ID (4.4.4.4) (Process ID 1)
Summary ASB Link States (Area 0)
LS age: 1230
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(AS Boundary Router)
Link State ID: 5.5.5.5 (AS Boundary Router address)
Advertising Router: 4.4.4.4
LS Seq Number: 80000002
Checksum: 0x9C3A
Length: 28
Network Mask: /0
TOS: 0 Metric: 64
Summary ASB Link States (Area 2)
LS age: 1487
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(AS Boundary Router)
Link State ID: 3.3.3.3 (AS Boundary Router address)
Advertising Router: 4.4.4.4
LS Seq Number: 80000002
Checksum: 0x809D
Length: 28
Network Mask: /0
TOS: 0 Metric: 1
自主系统外部LSA（Autonomous System External LSA）
产生：ASBR路由器
内容：自治系统外部的目的地/缺省路由的LSA/代价
泛洪范围：整个OSPF
查看命令:show ip ospf database external
图片解析:
命令查看：
R5#
R5#sh ip ospf database external
OSPF Router with ID (5.5.5.5) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 338
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 192.167.3.0 (External Network Number )
Advertising Router: 3.3.3.3
LS Seq Number: 80000003
Checksum: 0xC264
Length: 36
Network Mask: /24
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: 279
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 218.2.115.0 (External Network Number )
Advertising Router: 5.5.5.5
LS Seq Number: 80000003
Checksum: 0x2218
Length: 36
Network Mask: /24
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0
没有看到转发地址~~~
组成员LSA：组播OSPF协议中
NSSA外部LSA （NSSA External LSA）
产生：ASBR产生
内容：和自主系统外部LSA通告是相同。至于为什么要有这个看下面的末梢区域的解释
查看命令：show ip ospf database nssa-external
泛洪范围：非纯末梢区域
命令查看：
R5#show ip ospf database nssa-external
OSPF Router with ID (5.5.5.5) (Process ID 1)
Type-7 AS External Link States (Area 2)
Routing Bit Set on this LSA
LS age: 549
Options: (No TOS-capability, No Type 7/5 translation, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 4.4.4.4
LS Seq Number: 80000001
Checksum: 0xE8F8
Length: 36
Network Mask: /0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 172.16.2.1
External Route Tag: 0
LS age: 389
Options: (No TOS-capability, Type 7/5 translation, DC)
LS Type: AS External Link
Link State ID: 218.2.115.0 (External Network Number )
Advertising Router: 5.5.5.5
LS Seq Number: 80000001
Checksum: 0xE68B
Length: 36
Network Mask: /24
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 172.16.1.2
External Route Tag: 0
