2.6 OSPF LSA过滤、overflow

3.LSDB的Overflow

1）设置R3的OSPF缺省路由为8条（减少了自己生成的非缺省外部路由）

[R3]ospf 1
[R3-ospf-1]lsdb-overflow-limit 8
[R3]display ospf lsdb    

         OSPF Process 1 with Router ID 3.3.3.3
                 Link State Database 

                         Area: 0.0.0.1
 Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
 Router    2.2.2.2         2.2.2.2            946  48    8000001C       0
 Router    3.3.3.3         3.3.3.3            935  36    80000019       1
 Network   23.1.1.3        3.3.3.3            935  32    80000002       0
 Sum-Net   14.0.0.0        2.2.2.2           1393  28    80000002       2
 Sum-Net   24.0.0.0        2.2.2.2           1393  28    80000002       1
 Sum-Net   12.0.0.0        2.2.2.2           1393  28    80000002       1
 Sum-Asbr  1.1.1.1         2.2.2.2           1393  28    80000002       1

                 AS External Database
 Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
 External  11.1.2.1        1.1.1.1           1519  36    80000002       1
 External  11.1.3.1        1.1.1.1           1519  36    80000002       1
 External  11.1.1.1        1.1.1.1           1519  36    80000002       1
 External  14.0.0.0        1.1.1.1           1519  36    80000002       1
 External  12.0.0.0        1.1.1.1           1519  36    80000002       1
 External  1.1.1.1         1.1.1.1           1519  36    80000002       1

2）删除R1的LoopBack1地址，R3查看LSDB

[R1]interface LoopBack 1
[R1-LoopBack1]undo ip address 
[R3]display ospf lsdb
         OSPF Process 1 with Router ID 3.3.3.3
                 Link State Database 
                         Area: 0.0.0.1
 Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
 Router    2.2.2.2         2.2.2.2           1144  48    8000001C       0
 Router    3.3.3.3         3.3.3.3           1133  36    80000019       1
 Network   23.1.1.3        3.3.3.3           1133  32    80000002       0
 Sum-Net   14.0.0.0        2.2.2.2           1591  28    80000002       2
 Sum-Net   24.0.0.0        2.2.2.2           1591  28    80000002       1
 Sum-Net   12.0.0.0        2.2.2.2           1591  28    80000002       1
 Sum-Asbr  1.1.1.1         2.2.2.2           1591  28    80000002       1
                 AS External Database
 Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
 External  14.0.0.0        1.1.1.1           1717  36    80000002       1
 External  12.0.0.0        1.1.1.1           1717  36    80000002       1
 External  1.1.1.1         1.1.1.1           1717  36    80000002       1

3）5秒的Overflow定时器后，R3会将自己的5条外部路由添加

[R1]interface LoopBack 0
[R1-LoopBack0]undo ip address 
//为确保LSDB外部路由少于8，删除R1LoopBack 0地址
<R3>display ospf lsdb
OSPF Process 1 with Router ID 3.3.3.3
                 Link State Database 

                         Area: 0.0.0.1
 Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
 Router    2.2.2.2         2.2.2.2            119  48    8000001D       0
 Router    3.3.3.3         3.3.3.3            109  36    8000001A       1
 Network   23.1.1.3        3.3.3.3            109  32    80000003       0
 Sum-Net   14.0.0.0        2.2.2.2            566  28    80000003       2
 Sum-Net   24.0.0.0        2.2.2.2            566  28    80000003       1
 Sum-Net   12.0.0.0        2.2.2.2            566  28    80000003       1
 Sum-Asbr  1.1.1.1         2.2.2.2            566  28    80000003       1

                 AS External Database
 Type      LinkState ID    AdvRouter          Age  Len   Sequence   Metric
 External  33.1.2.1        3.3.3.3            353  36    80000001       1
 External  33.1.3.1        3.3.3.3            353  36    80000001       1
 External  33.1.1.1        3.3.3.3            353  36    80000001       1
 External  23.0.0.0        3.3.3.3            353  36    80000001       1
 External  3.3.3.3         3.3.3.3            353  36    80000001       1
 External  14.0.0.0        1.1.1.1            692  36    80000003       1
 External  12.0.0.0        1.1.1.1            692  36    80000003       1

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