OSPF 特殊区域
OSPF 特殊区域
什么时候使用特殊区域
(目的：减少 LSDB 的规模)
1. 网络末端
2. 路由器性能低下
Stub 区域
Stub (末节区域)
Stub 中只有 1LSA,2LSA,3LSA 以及一个描述缺省路由的 3LSA
LSA5,LSA4 不允许发布到 STUB 区域中，到达 AS 外的路由只能基于 ABR 生成的默认路由
STUB 区域可以减少 STUB 区域内路由器的 LSDB 规模和对设备的需求
[R6-ospf-1-area-0.0.0.1]stub
[R4-ospf-1-area-0.0.0.1]stub
[R6]dis ospf lsdb
OSPF Process 1 with Router ID 6.6.6.6
Link State Database
Area: 0.0.0.1
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 4.4.4.4 4.4.4.4 95 36 80000003 1
Router 6.6.6.6 6.6.6.6 94 84 80000007 1
Network 46.1.1.6 6.6.6.6 94 32 80000001 0
Sum-Net 5.5.5.5 4.4.4.4 85 28 80000001 50
Sum-Net 3.3.3.3 4.4.4.4 90 28 80000001 49
Sum-Net 14.1.1.0 4.4.4.4 128 28 80000001 48
Sum-Net 123.1.1.0 4.4.4.4 117 28 80000001 49
Sum-Net 4.4.4.4 4.4.4.4 137 28 80000001 0
Sum-Net 2.2.2.2 4.4.4.4 85 28 80000001 49
Sum-Net 25.1.1.0 4.4.4.4 85 28 80000001 50
Sum-Net 1.1.1.1 4.4.4.4 117 28 80000001 48
Sum-Asbr 5.5.5.5 4.4.4.4 85 28 80000001 50
AS External Database
Type LinkState ID AdvRouter Age Len Sequence Metric
External 20.1.0.0 5.5.5.5 151 36 80000001 2
External 7.7.7.7 5.5.5.5 151 36 80000001 1
External 5.5.5.5 5.5.5.5 160 36 80000001 1
External 25.1.1.0 5.5.5.5 131 36 80000001 1
External 57.1.1.0 5.5.5.5 151 36 80000001 1
[R6]ospf 1
[R6-ospf-1]a 1
[R6-ospf-1-area-0.0.0.1]stub ?
no-summary Do not send summary LSA into stub area
<cr> Please press ENTER to execute command
[R6-ospf-1-area-0.0.0.1]stub
[R4]ospf 1
[R4-ospf-1]a 1
[R4-ospf-1-area-0.0.0.1]stub
[R6-ospf-1-area-0.0.0.1]dis ospf lsdb
OSPF Process 1 with Router ID 6.6.6.6
Link State Database
Area: 0.0.0.1
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 4.4.4.4 4.4.4.4 41 36 80000004 1
Router 6.6.6.6 6.6.6.6 40 84 80000005 1
Network 46.1.1.6 6.6.6.6 40 32 80000001 0
Sum-Net 0.0.0.0 4.4.4.4 86 28 80000001 1
Sum-Net 5.5.5.5 4.4.4.4 86 28 80000001 50
Sum-Net 3.3.3.3 4.4.4.4 86 28 80000001 49
Sum-Net 14.1.1.0 4.4.4.4 86 28 80000001 48
Sum-Net 123.1.1.0 4.4.4.4 86 28 80000001 49
Sum-Net 4.4.4.4 4.4.4.4 86 28 80000001 0
Sum-Net 2.2.2.2 4.4.4.4 86 28 80000001 49
Sum-Net 25.1.1.0 4.4.4.4 86 28 80000001 50
Sum-Net 1.1.1.1 4.4.4.4 86 28 80000001 48
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Totally Stub 区域
Totally Stub (完全末节区域): 只有 1LSA,2LSA 以及一条描述缺省路由的 3LSA
(所有的 Stub 区域都无法引入外部路由)
[R6-ospf-1-area-0.0.0.1]stub no-summary
[R4-ospf-1-area-0.0.0.1]stub no-summary
[R6-ospf-1-area-0.0.0.1]dis ospf lsdb
OSPF Process 1 with Router ID 6.6.6.6
Link State Database
Area: 0.0.0.1
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 4.4.4.4 4.4.4.4 35 36 80000009 1
Router 6.6.6.6 6.6.6.6 32 84 8000000B 1
Network 46.1.1.6 6.6.6.6 32 32 80000002 0
Sum-Net 0.0.0.0 4.4.4.4 280 28 80000001 1
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NSSA 区域
NSSA (次末节区域): 不接受且不生成 4LSA,5LSA, 但可以引入外部路由，会生成一个 7LSA, 描述外部路由。同时 ABR 生成一个缺省路由，由 7LSA 描述。其他的普通区域不认识 7LSA,ABR 会将 7LSA 转换成 5LSA 进行泛洪.
[R2]ospf 1
[R2-ospf-1]a 2
[R2-ospf-1-area-0.0.0.2]nssa
[R5]ospf 1
[R5-ospf-1]a 2
[R5-ospf-1-area-0.0.0.2]nssa
<R2>reset ospf 1 process
<R5>reset ospf 1 process
<R5>dis ospf lsdb
OSPF Process 1 with Router ID 5.5.5.5
Link State Database
Area: 0.0.0.2
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 2.2.2.2 2.2.2.2 50 36 80000004 1
Router 5.5.5.5 5.5.5.5 41 48 80000006 1
Network 25.1.1.5 5.5.5.5 41 32 80000002 0
Sum-Net 6.6.6.6 2.2.2.2 39 28 80000001 50
Sum-Net 3.3.3.3 2.2.2.2 51 28 80000001 1
Sum-Net 14.1.1.0 2.2.2.2 39 28 80000001 49
Sum-Net 123.1.1.0 2.2.2.2 88 28 80000001 1
Sum-Net 46.1.1.0 2.2.2.2 39 28 80000001 50
Sum-Net 4.4.4.4 2.2.2.2 39 28 80000001 49
Sum-Net 2.2.2.2 2.2.2.2 88 28 80000001 0
Sum-Net 1.1.1.1 2.2.2.2 39 28 80000001 1
Sum-Net 10.1.0.0 2.2.2.2 39 28 80000001 50
NSSA 20.1.0.0 5.5.5.5 91 36 80000001 2
NSSA 7.7.7.7 5.5.5.5 91 36 80000001 1
NSSA 5.5.5.5 5.5.5.5 95 36 80000002 1
NSSA 25.1.1.0 5.5.5.5 87 36 80000001 1
NSSA 57.1.1.0 5.5.5.5 91 36 80000001 1
NSSA 0.0.0.0 2.2.2.2 51 36 80000001 1
<R2>dis ospf lsdb
OSPF Process 1 with Router ID 2.2.2.2
Link State Database
Area: 0.0.0.0
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 4.4.4.4 4.4.4.4 154 60 80000006 0
Router 2.2.2.2 2.2.2.2 119 48 80000009 1
Router 1.1.1.1 1.1.1.1 125 72 8000000B 1
Router 3.3.3.3 3.3.3.3 120 48 8000000A 1
Network 123.1.1.3 3.3.3.3 120 36 80000005 0
Sum-Net 6.6.6.6 4.4.4.4 140 28 80000001 1
Sum-Net 5.5.5.5 2.2.2.2 132 28 80000001 1
Sum-Net 46.1.1.0 4.4.4.4 180 28 80000001 1
Sum-Net 25.1.1.0 2.2.2.2 172 28 80000001 1
Sum-Net 10.1.0.0 4.4.4.4 140 28 80000001 1
Area: 0.0.0.2
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 2.2.2.2 2.2.2.2 134 36 80000004 1
Router 5.5.5.5 5.5.5.5 127 48 80000006 1
Network 25.1.1.5 5.5.5.5 127 32 80000002 0
Sum-Net 6.6.6.6 2.2.2.2 123 28 80000001 50
Sum-Net 3.3.3.3 2.2.2.2 135 28 80000001 1
Sum-Net 14.1.1.0 2.2.2.2 123 28 80000001 49
Sum-Net 123.1.1.0 2.2.2.2 172 28 80000001 1
Sum-Net 46.1.1.0 2.2.2.2 123 28 80000001 50
Sum-Net 4.4.4.4 2.2.2.2 123 28 80000001 49
Sum-Net 2.2.2.2 2.2.2.2 172 28 80000001 0
Sum-Net 1.1.1.1 2.2.2.2 123 28 80000001 1
Sum-Net 10.1.0.0 2.2.2.2 123 28 80000001 50
NSSA 0.0.0.0 2.2.2.2 135 36 80000001 1
NSSA 20.1.0.0 5.5.5.5 177 36 80000001 2
NSSA 7.7.7.7 5.5.5.5 177 36 80000001 1
NSSA 5.5.5.5 5.5.5.5 182 36 80000002 1
NSSA 25.1.1.0 5.5.5.5 174 36 80000001 1
NSSA 57.1.1.0 5.5.5.5 178 36 80000001 1
AS External Database
Type LinkState ID AdvRouter Age Len Sequence Metric
External 20.1.0.0 2.2.2.2 133 36 80000001 2
External 7.7.7.7 2.2.2.2 133 36 80000001 1
External 57.1.1.0 2.2.2.2 133 36 80000001 1
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Totally NSSA 区域
Totally NSSA (完全次末节区域): 只有 1LSA,2LSA,7LSA 和一条描述缺省路由的 3LSA, 一条描述缺省路由的 7LSA
骨干区域不能作为特殊区域
虚连接不能穿越骨干区域
[R5]ospf
[R5-ospf-1]a 2
[R5-ospf-1-area-0.0.0.2]nssa no-summary
[R2]ospf
[R2-ospf-1]a 2
[R2-ospf-1-area-0.0.0.2]nssa no-summary
[R5-ospf-1-area-0.0.0.2]dis ospf lsdb
OSPF Process 1 with Router ID 5.5.5.5
Link State Database
Area: 0.0.0.2
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 2.2.2.2 2.2.2.2 34 36 8000000A 1
Router 5.5.5.5 5.5.5.5 33 48 8000000C 1
Network 25.1.1.2 2.2.2.2 34 32 80000002 0
Sum-Net 0.0.0.0 2.2.2.2 56 28 80000001 1
NSSA 20.1.0.0 5.5.5.5 44 36 80000003 2
NSSA 7.7.7.7 5.5.5.5 44 36 80000001 1
NSSA 5.5.5.5 5.5.5.5 44 36 80000002 1
NSSA 25.1.1.0 5.5.5.5 44 36 80000001 1
NSSA 57.1.1.0 5.5.5.5 44 36 80000001 1
NSSA 0.0.0.0 2.2.2.2 56 36 80000001 1
[R2-ospf-1-area-0.0.0.2]dis ospf lsdb
OSPF Process 1 with Router ID 2.2.2.2
Link State Database
Area: 0.0.0.0
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 4.4.4.4 4.4.4.4 575 60 80000006 0
Router 2.2.2.2 2.2.2.2 540 48 80000009 1
Router 1.1.1.1 1.1.1.1 546 72 8000000B 1
Router 3.3.3.3 3.3.3.3 541 48 8000000A 1
Network 123.1.1.3 3.3.3.3 541 36 80000005 0
Sum-Net 6.6.6.6 4.4.4.4 561 28 80000001 1
Sum-Net 5.5.5.5 2.2.2.2 28 28 80000001 1
Sum-Net 46.1.1.0 4.4.4.4 601 28 80000001 1
Sum-Net 25.1.1.0 2.2.2.2 51 28 80000002 1
Sum-Net 10.1.0.0 4.4.4.4 561 28 80000001 1
Area: 0.0.0.2
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 2.2.2.2 2.2.2.2 29 36 8000000A 1
Router 5.5.5.5 5.5.5.5 30 48 8000000C 1
Network 25.1.1.2 2.2.2.2 29 32 80000002 0
Sum-Net 0.0.0.0 2.2.2.2 51 28 80000001 1
NSSA 0.0.0.0 2.2.2.2 51 36 80000001 1
NSSA 20.1.0.0 5.5.5.5 41 36 80000003 2
NSSA 7.7.7.7 5.5.5.5 598 36 80000001 1
NSSA 5.5.5.5 5.5.5.5 602 36 80000002 1
NSSA 25.1.1.0 5.5.5.5 594 36 80000001 1
NSSA 57.1.1.0 5.5.5.5 598 36 80000001 1
AS External Database
Type LinkState ID AdvRouter Age Len Sequence Metric
External 20.1.0.0 2.2.2.2 28 36 80000001 2
External 7.7.7.7 2.2.2.2 28 36 80000001 1
External 57.1.1.0 2.2.2.2 28 36 80000001 1
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