oapf_LSA类型

LSA（链路状态通告）类型

LSA Type	Description
1	Router LSAs:
2	Network LSAs
3&4	Summary LSAs
5	Autonomous system external LSAs
6	Multicast OSPF LSA
7	Defined for not-so-stubby areas
8	External attributes LSA for Border Gateway Protocol (BGP)
9, 10, 11	Opaque LSAs

1、router LSAs（一类）
路由器LSA：没一台路由器都会产生路由器LSA。这个最基本的LSA通告列出了路由器所有的链路或接口，并且指明了他们的状态和沿每条链路方向出站的开销，以及该链路上的所有OSPF邻居





以上拓扑所示的两台路由器都已经配置好。
使用R1#show ip ospf database router得到下面的信息
OSPF Router with ID (1.1.1.1) (Process ID 1)
Router Link States (Area 0)
LS age: 176
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 1.1.1.1 注：使用的是router-ID
Advertising Router: 1.1.1.1
LS Seq Number: 80000004
Checksum: 0x65F9
Length: 60
Number of Links: 3

Link connected to: a Stub Network
(Link ID) Network/subnet number: 1.1.1.1
(Link Data) Network Mask: 255.255.255.255 【这个是由他的网络类型决定的，默认是LOOPBACK，修改为点对点之后就会不一样了(Link ID) Network/subnet number: 1.1.1.0
(Link Data) Network Mask: 255.255.255.0】
Number of TOS metrics: 0
TOS 0 Metrics: 1 【开销，出接口】

Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 2.2.2.2
(Link Data) Router Interface address: 12.1.1.1
Number of TOS metrics: 0
TOS 0 Metrics: 64

Link connected to: a Stub Network
(Link ID) Network/subnet number: 12.1.1.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 64
综上所得：R2学到R1还回口的开销等于:64+1=65
R2#show ip route ospf
1.0.0.0/24 is subnetted, 1 subnets
O 1.1.1.0 [110/65] via 12.1.1.1, 00:03:07, Serial1/0
2、network LSA（二类）
网络LSA，每一个多路访问的网络中的指定路由器（DR）将会产生网络LSA。




R4#show ip ospf database network

OSPF Router with ID (4.4.4.4) (Process ID 1)

Net Link States (Area 2)

Routing Bit Set on this LSA
LS age: 256
Options: (No TOS-capability, DC)
LS Type: Network Links
Link State ID: 34.1.1.1 (address of Designated Router) 指定路由器与邻居相连的接口IP。
Advertising Router: 3.3.3.3
LS Seq Number: 80000001
Checksum: 0x9755
Length: 32
Network Mask: /24 说明一下的地址的子网掩码都是24位
Attached Router: 3.3.3.3 都是Router ID
Attached Router: 4.4.4.4

3、summary LSA （三类）
自治系统内汇总的LSA，由ABR路由器发出的LSA。ABR路由器将发送网络汇总LSA到一个区域，用来通告该区域外部的目的地址。





在R2上做区域汇总：R2(config-router)#area 0 range 1.1.0.0 255.255.252.0
在R3查看路由表和链路状态数据库
R3#show ip route ospf
1.0.0.0/22 is subnetted, 1 subnets
O IA 1.1.0.0 [110/129] via 23.1.1.1, 00:03:33, Serial1/0
12.0.0.0/24 is subnetted, 1 subnets
O IA 12.1.1.0 [110/128] via 23.1.1.1, 00:03:33, Serial1/0
R3#show ip ospf database summary

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

Summary Net Link States (Area 1)

Routing Bit Set on this LSA
LS age: 240
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 1.1.0.0 (summary Network Number) //汇总的网络号
Advertising Router: 23.1.1.1
LS Seq Number: 80000001
Checksum: 0x9D9
Length: 28
Network Mask: /22 //汇总后的子网掩码
TOS: 0 Metric: 65

Routing Bit Set on this LSA
LS age: 240
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 12.1.1.0 (summary Network Number) //汇总的网络号
Advertising Router: 23.1.1.1
LS Seq Number: 80000001
Checksum: 0x7361
Length: 28
Network Mask: /24 //汇总后的子网掩码，这里没有进行汇总，所以不变
TOS: 0 Metric: 64

R3学到R1环回口IP地址所需要的开销计算：
要到达1.1.0.0网段首先要到23.1.1.1即R2使用一类LSA可以达到。
其次是使用汇总LSA，两者相加就可以得到了
R3#show ip ospf database route

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

Router Link States (Area 1)
Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 23.1.1.1
(Link Data) Router Interface address: 23.1.1.2
Number of TOS metrics: 0
TOS 0 Metrics: 64
R3# show ip ospf database summary
Link State ID: 1.1.0.0 (summary Network Number)
Advertising Router: 23.1.1.1
LS Seq Number: 80000001
Checksum: 0x9D9
Length: 28
Network Mask: /22
TOS: 0 Metric: 65
64+65=129