OSPF的LSA类型 ——连载三网络汇总LSA
图1：
（基本配置见“OSPF的LSA类型 ——连载一”）
3类 网络汇总LSA
网络汇总LSA通告的是一个区域外部的网络（包括缺省路由），在区域间传递的LSA，且只能在单个区域中泛洪。一条LSA信息即是一条路由信息。
LSA传播范围：域间路由，能泛洪到整个AS中，始发路由器除外。
LSA通告路由器：ABR的Router ID（经过一个ABR，就会改为这个ABR的Router ID）
LSA链路状态ID：网络号
LSA包含的内容：本区域中的路由信息，包括网络号和掩码
show ip ospf database summary 查看一条网络汇总LSA
R4# show ip ospf database summary
OSPF Router with ID (4.4.4 .4) (Process ID 110)
Summary Net Link States (Area 1)
Routing Bit Set on this LSA
LS age: 1126
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 12.1.1 .0 (summary Network Number) //传递进该区域的网络号作为链路状态ID
Advertising Router: 2.2.2 .2 // ABR的Router ID
LS Seq Number: 80000004
Checksum: 0xF722
Length: 28
Network Mask: /24
TOS: 0 Metric: 10 // Metric=10，通往12.1.1 .0网路走的是以太网络
Routing Bit Set on this LSA
LS age: 1126
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 13.1.1 .0 (summary Network Number)
Advertising Router: 2.2.2 .2
LS Seq Number: 80000004
Checksum: 0x6D6B
Length: 28
Network Mask: /24
TOS: 0 Metric: 74
Routing Bit Set on this LSA
LS age: 1128
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 35.1.1.0 (summary Network Number)
Advertising Router: 2.2.2 .2
LS Seq Number: 80000002
Checksum: 0xD4AF
Length: 28
Network Mask: /24
TOS: 0 Metric: 138
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R4#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF , IA
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
35.0.0.0/24 is subnetted, 1 subnets
O IA 35.1.1.0 [110/202] via 24.1.1.2, 01:02:28, Serial1/1
// O IA= OSPF inter area，24.1.1.2说发往35.1.1.0的数据包全部转给我，因为我是ABR。
3类LSA学习区域间的路由，并将其泛洪到区域中的其他路由器。但不会在泛洪给始发给它的那台。
24.0.0.0/24 is subnetted, 1 subnets
C 24.1.1.0 is directly connected, Serial1/1
O IA 12.1.1 .0 [110/74] via 24.1.1.2, 01:02:34, Serial1/1
O IA 13.1.1 .0 [110/138] via 24.1.1.2, 01:02:24, Serial1/1
