OSPF-缺省路由注入（default-route-advertise&default-route-advertise always）
关于OSPD的路由注入使用import-route命令。
import-route命令只能注入明细路由，直连路由，外部协议路由；但是不能注入缺省路由，默认路由。
AR4有一条默认路由指向外部网络，import-route不能注入缺省路由，内部路由器不能学习到默认路由，即内部网络无法访问外部网络。
我们通过default-route-advertise&default-route-advertise always其中一个命令注入缺省路由
一：default-route-advertise 使用
default-route-advertise：向内部路由器宣告自身的默认路由
[AR4]display ip routing-table 0.0.0.0 #目前自身没有默认路由 [AR4]ospf [AR4-ospf-1]default-route-advertise #进入协议，配置
查看内部路由器路由表，确认是否有新默认的路由
<AR1>dis ip routing-table 0.0.0.0 <AR1> #显示没有新的默认路由
由于AR4本身没有默认路由，所以内部路由器不会学习到新的默认路由
为AR4添加默认路由
[AR4]ip route-static 0.0.0.0 0.0.0.0 GigabitEthernet0/0/1 202.102.1.1 [AR4]dis ip ro [AR4]dis ip routing-table 0.0.0.0 Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Table : Public Summary Count : 1 Destination/Mask Proto Pre Cost Flags NextHop Interface 0.0.0.0/0 Static 60 0 D 202.102.1.1 GigabitEthernet 0/0/1 [AR4]
为AR4添加完默认路由后，再次查看内部路由器路由
<AR1>dis ip routing-table 0.0.0.0 Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Table : Public Summary Count : 1 Destination/Mask Proto Pre Cost Flags NextHop Interface 0.0.0.0/0 O_ASE 150 1 D 10.1.13.3 GigabitEthernet 0/0/1 <AR1>dis ospf ls <AR1>dis ospf lsdb OSPF Process 1 with Router ID 1.1.1.1 Link State Database Area: 0.0.0.0 Type LinkState ID AdvRouter Age Len Sequence Metric Router 2.2.2.2 2.2.2.2 596 60 8000000C 10 Router 1.1.1.1 1.1.1.1 598 60 8000000B 10 Router 3.3.3.3 3.3.3.3 597 60 8000000D 5 Network 10.1.23.3 3.3.3.3 601 32 80000004 0 Network 10.1.13.3 3.3.3.3 597 32 80000004 0 Network 10.1.12.2 2.2.2.2 596 32 80000004 0 Sum-Net 10.1.35.0 3.3.3.3 649 28 80000003 1 Sum-Net 10.1.34.0 3.3.3.3 649 28 80000003 1 Sum-Net 5.5.5.5 3.3.3.3 611 28 80000003 1 Sum-Net 4.4.4.4 3.3.3.3 604 28 80000003 1 Sum-Net 202.102.1.0 3.3.3.3 604 28 80000003 2 Sum-Asbr 4.4.4.4 3.3.3.3 736 28 80000002 1 AS External Database Type LinkState ID AdvRouter Age Len Sequence Metric External 0.0.0.0 4.4.4.4 181 36 80000001 1 <AR1>dis ospf lsdb ase 0.0.0.0 OSPF Process 1 with Router ID 1.1.1.1 Link State Database Type : External Ls id : 0.0.0.0 Adv rtr : 4.4.4.4 Ls age : 193 Len : 36 Options : E seq# : 80000001 chksum : 0x2568 Net mask : 0.0.0.0 TOS 0 Metric: 1 E type : 2 Forwarding Address : 202.102.1.1 Tag : 1 Priority : Low <AR1>
AR4添加完默认路由后，内部路由顺利学习到新的AR4上的默认路由。
二：default-route-advertise always 使用
default-route-advertise always与default-route-advertise 区别在于，如果自身没有缺省路由，设备自动生成默认路由的LSA发送内部路由器
[AR4-ospf-1]default-route-advertise always
<AR1>dis ip routing-table 0.0.0.0 Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Table : Public Summary Count : 1 Destination/Mask Proto Pre Cost Flags NextHop Interface 0.0.0.0/0 O_ASE 150 1 D 10.1.13.3 GigabitEthernet 0/0/1 <AR1>dis ospf lsdb OSPF Process 1 with Router ID 1.1.1.1 Link State Database Area: 0.0.0.0 Type LinkState ID AdvRouter Age Len Sequence Metric Router 2.2.2.2 2.2.2.2 298 60 8000000D 10 Router 1.1.1.1 1.1.1.1 300 60 8000000C 10 Router 3.3.3.3 3.3.3.3 300 60 8000000E 5 Network 10.1.23.3 3.3.3.3 303 32 80000005 0 Network 10.1.13.3 3.3.3.3 300 32 80000005 0 Network 10.1.12.2 2.2.2.2 298 32 80000005 0 Sum-Net 10.1.35.0 3.3.3.3 351 28 80000004 1 Sum-Net 10.1.34.0 3.3.3.3 351 28 80000004 1 Sum-Net 5.5.5.5 3.3.3.3 313 28 80000004 1 Sum-Net 4.4.4.4 3.3.3.3 306 28 80000004 1 Sum-Net 202.102.1.0 3.3.3.3 306 28 80000004 2 Sum-Asbr 4.4.4.4 3.3.3.3 1206 28 80000001 1 AS External Database Type LinkState ID AdvRouter Age Len Sequence Metric External 0.0.0.0 4.4.4.4 644 36 80000001 1 <AR1>dis ospf lsdb ase 0.0.0.0 OSPF Process 1 with Router ID 1.1.1.1 Link State Database Type : External Ls id : 0.0.0.0 Adv rtr : 4.4.4.4 Ls age : 653 Len : 36 Options : E seq# : 80000001 chksum : 0x863a Net mask : 0.0.0.0 TOS 0 Metric: 1 E type : 2 Forwarding Address : 0.0.0.0 Tag : 1 Priority : Low <AR1>
通过查询OSPD数据库得知，默认网段指向AR4，但是到达AR4后不会再转发出去。所以AR4上还必须补上一条指向外部的默认路由，内部网络才能正常访问外部网络。
[AR4]ip route-static 0.0.0.0 0.0.0.0 GigabitEthernet0/0/1 202.102.1.1
<AR1>dis ip routing-table 0.0.0.0
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Table : Public
Summary Count : 1
Destination/Mask Proto Pre Cost Flags NextHop Interface
0.0.0.0/0 O_ASE 150 1 D 10.1.13.3 GigabitEthernet
0/0/1
<AR1>dis ospf lsdb
OSPF Process 1 with Router ID 1.1.1.1
Link State Database
Area: 0.0.0.0
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 2.2.2.2 2.2.2.2 1176 60 8000000D 10
Router 1.1.1.1 1.1.1.1 1178 60 8000000C 10
Router 3.3.3.3 3.3.3.3 1178 60 8000000E 5
Network 10.1.23.3 3.3.3.3 1181 32 80000005 0
Network 10.1.13.3 3.3.3.3 1178 32 80000005 0
Network 10.1.12.2 2.2.2.2 1176 32 80000005 0
Sum-Net 10.1.35.0 3.3.3.3 1229 28 80000004 1
Sum-Net 10.1.34.0 3.3.3.3 1229 28 80000004 1
Sum-Net 5.5.5.5 3.3.3.3 1191 28 80000004 1
Sum-Net 4.4.4.4 3.3.3.3 1184 28 80000004 1
Sum-Net 202.102.1.0 3.3.3.3 1184 28 80000004 2
Sum-Asbr 4.4.4.4 3.3.3.3 283 28 80000002 1
AS External Database
Type LinkState ID AdvRouter Age Len Sequence Metric
External 0.0.0.0 4.4.4.4 101 36 80000002 1
<AR1>dis ospf lsdb ase 0.0.0.0
OSPF Process 1 with Router ID 1.1.1.1
Link State Database
Type : External
Ls id : 0.0.0.0
Adv rtr : 4.4.4.4
Ls age : 109
Len : 36
Options : E
seq# : 80000002
chksum : 0x2369
Net mask : 0.0.0.0
TOS 0 Metric: 1
E type : 2
Forwarding Address : 202.102.1.1
Tag : 1
Priority : Low
<AR1>
AR4增加默认路由后，查看OSPD数据库，路由表，发现0.0.0.0到达AR4后的下一跳地址指向了外部网络互联地址
三：特殊区域（nssa区域）的缺省路由宣告方式：nssa default-route-advertise
nssa区域需要ASBR宣告缺省路由，使得nssa区域的路由器学习到外部缺省路由。然后再通过ABR向内部路由器宣告缺省路由。
未宣告缺省路由前AR1，AR3，AR4的OSPF数据库
AR1路由器OSPF数据库中没有缺省路由
<AR1>dis ospf lsdb OSPF Process 1 with Router ID 1.1.1.1 Link State Database Area: 0.0.0.0 Type LinkState ID AdvRouter Age Len Sequence Metric Router 2.2.2.2 2.2.2.2 928 60 8000000A 10 Router 1.1.1.1 1.1.1.1 930 60 8000000A 10 Router 3.3.3.3 3.3.3.3 700 60 8000000D 5 Network 10.1.23.3 3.3.3.3 939 32 80000002 0 Network 10.1.13.3 3.3.3.3 929 32 80000003 0 Network 10.1.12.2 2.2.2.2 928 32 80000003 0 Sum-Net 10.1.35.0 3.3.3.3 980 28 80000002 1 Sum-Net 10.1.34.0 3.3.3.3 700 28 80000003 1 Sum-Net 5.5.5.5 3.3.3.3 942 28 80000002 1 Sum-Net 4.4.4.4 3.3.3.3 660 28 80000002 1 Sum-Net 202.102.1.0 3.3.3.3 660 28 80000002 2
AR3和AR4所属区域1 拥有sum-net和nssa的0.0.0.0 链路信息，sum-net对普通区域发送，nssa针对nssa内部路由器发送
[AR3-ospf-1-area-0.0.0.1]dis ospf lsdb OSPF Process 1 with Router ID 3.3.3.3 Link State Database Area: 0.0.0.0 Type LinkState ID AdvRouter Age Len Sequence Metric Router 2.2.2.2 2.2.2.2 996 60 8000000A 10 Router 1.1.1.1 1.1.1.1 999 60 8000000A 10 Router 3.3.3.3 3.3.3.3 767 60 8000000D 5 Network 10.1.23.3 3.3.3.3 1005 32 80000002 0 Network 10.1.13.3 3.3.3.3 995 32 80000003 0 Network 10.1.12.2 2.2.2.2 996 32 80000003 0 Sum-Net 10.1.35.0 3.3.3.3 1047 28 80000002 1 Sum-Net 10.1.34.0 3.3.3.3 767 28 80000003 1 Sum-Net 5.5.5.5 3.3.3.3 1008 28 80000002 1 Sum-Net 4.4.4.4 3.3.3.3 726 28 80000002 1 Sum-Net 202.102.1.0 3.3.3.3 726 28 80000002 2 Area: 0.0.0.1 Type LinkState ID AdvRouter Age Len Sequence Metric Router 4.4.4.4 4.4.4.4 32 60 8000000A 1 Router 3.3.3.3 3.3.3.3 726 36 80000005 1 Network 10.1.34.4 4.4.4.4 727 32 80000002 0 Sum-Net 0.0.0.0 3.3.3.3 767 28 80000002 1 NSSA 0.0.0.0 3.3.3.3 767 36 80000002 1 Area: 0.0.0.2 Type LinkState ID AdvRouter Age Len Sequence Metric Router 5.5.5.5 5.5.5.5 1001 48 80000007 1 Router 3.3.3.3 3.3.3.3 767 36 80000006 1 Network 10.1.35.5 5.5.5.5 1001 32 80000003 0 Sum-Net 10.1.23.0 3.3.3.3 1047 28 80000002 5 Sum-Net 10.1.34.0 3.3.3.3 767 28 80000003 1 Sum-Net 10.1.13.0 3.3.3.3 1042 28 80000002 5 Sum-Net 3.3.3.3 3.3.3.3 1047 28 80000002 0 Sum-Net 10.1.12.0 3.3.3.3 998 28 80000003 15 Sum-Net 4.4.4.4 3.3.3.3 726 28 80000002 1 Sum-Net 2.2.2.2 3.3.3.3 1006 28 80000002 5 Sum-Net 202.102.1.0 3.3.3.3 727 28 80000002 2 Sum-Net 1.1.1.1 3.3.3.3 1003 28 80000002 5 [AR3-ospf-1-area-0.0.0.1]dis ospf lsdb summary 0.0.0.0 OSPF Process 1 with Router ID 3.3.3.3 Area: 0.0.0.0 Link State Database Area: 0.0.0.1 Link State Database Type : Sum-Net Ls id : 0.0.0.0 Adv rtr : 3.3.3.3 Ls age : 780 Len : 28 Options : None seq# : 80000002 chksum : 0x371a Net mask : 0.0.0.0 Tos 0 metric: 1 Priority : Low Area: 0.0.0.2 Link State Database [AR3-ospf-1-area-0.0.0.1]dis ospf lsdb nssa 0.0.0.0 OSPF Process 1 with Router ID 3.3.3.3 Area: 0.0.0.0 Link State Database Area: 0.0.0.1 Link State Database Type : NSSA Ls id : 0.0.0.0 Adv rtr : 3.3.3.3 Ls age : 789 Len : 36 Options : None seq# : 80000002 chksum : 0xa41f Net mask : 0.0.0.0 TOS 0 Metric: 1 E type : 2 Forwarding Address : 0.0.0.0 Tag : 1 Priority : Low Area: 0.0.0.2 Link State Database [AR3-ospf-1-area-0.0.0.1]dis ip routing-table 0.0.0.0 [AR3-ospf-1-area-0.0.0.1]
[AR4]dis ospf lsdb OSPF Process 1 with Router ID 4.4.4.4 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 1603 60 80000009 1 Router 3.3.3.3 3.3.3.3 501 36 80000005 1 Network 10.1.34.4 4.4.4.4 500 32 80000002 0 Sum-Net 0.0.0.0 3.3.3.3 542 28 80000002 1 NSSA 0.0.0.0 3.3.3.3 542 36 80000002 1 [AR4]dis ospf ls [AR4]dis ospf lsdb ns [AR4]dis ospf lsdb nssa 0.0.0.0 OSPF Process 1 with Router ID 4.4.4.4 Area: 0.0.0.1 Link State Database Type : NSSA Ls id : 0.0.0.0 Adv rtr : 3.3.3.3 Ls age : 553 Len : 36 Options : None seq# : 80000002 chksum : 0xa41f Net mask : 0.0.0.0 TOS 0 Metric: 1 E type : 2 Forwarding Address : 0.0.0.0 Tag : 1 Priority : Low [AR4]dis ip ro [AR4]dis ip routing-table 0.0.0.0 Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Table : Public Summary Count : 1 Destination/Mask Proto Pre Cost Flags NextHop Interface 0.0.0.0/0 OSPF 10 2 D 10.1.34.3 GigabitEthernet 0/0/0 [AR4]dis ospf lsdb OSPF Process 1 with Router ID 4.4.4.4 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 1724 60 80000009 1 Router 3.3.3.3 3.3.3.3 622 36 80000005 1 Network 10.1.34.4 4.4.4.4 621 32 80000002 0 Sum-Net 0.0.0.0 3.3.3.3 663 28 80000002 1 NSSA 0.0.0.0 3.3.3.3 663 36 80000002 1 [AR4]dis ospf lsdb summary 0.0.0.0 OSPF Process 1 with Router ID 4.4.4.4 Area: 0.0.0.1 Link State Database Type : Sum-Net Ls id : 0.0.0.0 Adv rtr : 3.3.3.3 Ls age : 683 Len : 28 Options : None seq# : 80000002 chksum : 0x371a Net mask : 0.0.0.0 Tos 0 metric: 1 Priority : Low [AR4]dis ospf lsdb nssa 0.0.0.0 OSPF Process 1 with Router ID 4.4.4.4 Area: 0.0.0.1 Link State Database Type : NSSA Ls id : 0.0.0.0 Adv rtr : 3.3.3.3 Ls age : 690 Len : 36 Options : None seq# : 80000002 chksum : 0xa41f Net mask : 0.0.0.0 TOS 0 Metric: 1 E type : 2 Forwarding Address : 0.0.0.0 Tag : 1 Priority : Low [AR4]
AR4，配置默认路由，宣告默认路由配置
[AR4]ip route-static 0.0.0.0 0.0.0.0 GigabitEthernet0/0/1 202.102.1.1 [AR4]ospf [AR4-ospf-1]area 1 [AR4-ospf-1-area-0.0.0.1]nssa default-route-advertise
查看AR4的LSDB，默认路由：
[AR4]dis ip routing-table 0.0.0.0 0.0.0.0 Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Table : Public Summary Count : 1 Destination/Mask Proto Pre Cost Flags NextHop Interface 0.0.0.0/0 OSPF 10 2 D 10.1.34.3 GigabitEthernet 0/0/0 [AR4]dis ospf lsdb OSPF Process 1 with Router ID 4.4.4.4 Link State Database Area: 0.0.0.1 Type LinkState ID AdvRouter Age Len Sequence Metric Router 4.4.4.4 4.4.4.4 936 60 80000006 1 Router 3.3.3.3 3.3.3.3 937 36 80000004 1 Network 10.1.34.4 4.4.4.4 936 32 80000001 0 Sum-Net 0.0.0.0 3.3.3.3 976 28 80000001 1 NSSA 0.0.0.0 3.3.3.3 976 36 80000001 1
AR4宣告路由后，路由表和LSDB没有变化。因为华为选路规则中，OSPF优先级为10，静态路由优先级为60；所以路由表选择优先值低的静态路由。
因此，为了实现路由表选择静态路由，需要手动配置默认路由优先级，使优先值小于OSPF路由的优先值
[AR4]ip route-static 0.0.0.0 0.0.0.0 GigabitEthernet0/0/1 202.102.1.1 preference 5
[AR4]display ip routing-table 0.0.0.0
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Table : Public
Summary Count : 1
Destination/Mask Proto Pre Cost Flags NextHop Interface
0.0.0.0/0 Static 5 0 D 202.102.1.1 GigabitEthernet
0/0/1
[AR4]dis ospf ls
[AR4]dis ospf lsdb
OSPF Process 1 with Router ID 4.4.4.4
Link State Database
Area: 0.0.0.1
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 4.4.4.4 4.4.4.4 460 60 80000007 1
Router 3.3.3.3 3.3.3.3 461 36 80000005 1
Network 10.1.34.4 4.4.4.4 460 32 80000002 0
Sum-Net 0.0.0.0 3.3.3.3 500 28 80000002 1
NSSA 0.0.0.0 4.4.4.4 747 36 80000001 1
NSSA 0.0.0.0 3.3.3.3 500 36 80000002 1
[AR4]display ospf lsdb nssa 0.0.0.0 self-originate
OSPF Process 1 with Router ID 4.4.4.4
Area: 0.0.0.1
Link State Database
Type : NSSA
Ls id : 0.0.0.0
Adv rtr : 4.4.4.4
Ls age : 762
Len : 36
Options : None
seq# : 80000001
chksum : 0x2766
Net mask : 0.0.0.0
TOS 0 Metric: 1
E type : 2
Forwarding Address : 202.102.1.1
Tag : 1
Priority : Low
[AR4]
[AR3-ospf-1-area-0.0.0.1]dis ospf lsdb OSPF Process 1 with Router ID 3.3.3.3 Link State Database Area: 0.0.0.0 Type LinkState ID AdvRouter Age Len Sequence Metric Router 2.2.2.2 2.2.2.2 420 60 80000009 10 Router 1.1.1.1 1.1.1.1 424 60 80000009 10 Router 3.3.3.3 3.3.3.3 257 60 8000000C 5 Network 10.1.23.3 3.3.3.3 430 32 80000001 0 Network 10.1.13.3 3.3.3.3 420 32 80000002 0 Network 10.1.12.2 2.2.2.2 420 32 80000002 0 Sum-Net 10.1.35.0 3.3.3.3 472 28 80000001 1 Sum-Net 10.1.34.0 3.3.3.3 257 28 80000002 1 Sum-Net 5.5.5.5 3.3.3.3 429 28 80000001 1 Sum-Net 4.4.4.4 3.3.3.3 210 28 80000001 1 Sum-Net 202.102.1.0 3.3.3.3 210 28 80000001 2 Area: 0.0.0.1 Type LinkState ID AdvRouter Age Len Sequence Metric Router 4.4.4.4 4.4.4.4 211 60 80000006 1 Router 3.3.3.3 3.3.3.3 210 36 80000004 1 Network 10.1.34.4 4.4.4.4 211 32 80000001 0 Sum-Net 0.0.0.0 3.3.3.3 257 28 80000001 1 NSSA 0.0.0.0 3.3.3.3 257 36 80000001 1 NSSA 0.0.0.0 4.4.4.4 134 36 80000001 1 Area: 0.0.0.2 Type LinkState ID AdvRouter Age Len Sequence Metric Router 5.5.5.5 5.5.5.5 431 48 80000006 1 Router 3.3.3.3 3.3.3.3 257 36 80000004 1 Network 10.1.35.5 5.5.5.5 431 32 80000001 0 Sum-Net 10.1.23.0 3.3.3.3 472 28 80000001 5 Sum-Net 10.1.34.0 3.3.3.3 257 28 80000002 1 Sum-Net 10.1.13.0 3.3.3.3 469 28 80000001 5 Sum-Net 3.3.3.3 3.3.3.3 472 28 80000001 0 Sum-Net 10.1.12.0 3.3.3.3 423 28 80000002 15 Sum-Net 4.4.4.4 3.3.3.3 212 28 80000001 1 Sum-Net 2.2.2.2 3.3.3.3 432 28 80000001 5 Sum-Net 202.102.1.0 3.3.3.3 212 28 80000001 2 Sum-Net 1.1.1.1 3.3.3.3 429 28 80000001 5 [AR3-ospf-1-area-0.0.0.1]dis ospf ls [AR3-ospf-1-area-0.0.0.1]dis ospf lsdb ns [AR3-ospf-1-area-0.0.0.1]dis ospf lsdb nssa 0.0.0.0 or [AR3-ospf-1-area-0.0.0.1]dis ospf lsdb nssa 0.0.0.0 originate-router OSPF Process 1 with Router ID 3.3.3.3 Area: 0.0.0.0 Link State Database Area: 0.0.0.1 Link State Database Type : NSSA Ls id : 0.0.0.0 Adv rtr : 3.3.3.3 Ls age : 300 Len : 36 Options : None seq# : 80000001 chksum : 0xa61e Net mask : 0.0.0.0 TOS 0 Metric: 1 E type : 2 Forwarding Address : 0.0.0.0 Tag : 1 Priority : Low Type : NSSA Ls id : 0.0.0.0 Adv rtr : 4.4.4.4 Ls age : 177 Len : 36 Options : None seq# : 80000001 chksum : 0x2766 Net mask : 0.0.0.0 TOS 0 Metric: 1 E type : 2 Forwarding Address : 202.102.1.1 Tag : 1 Priority : Low Area: 0.0.0.2 Link State Database [AR3-ospf-1-area-0.0.0.1]dis ip ro [AR3-ospf-1-area-0.0.0.1]dis ip routing-table 0.0.0.0
此时内部路由器还没有学习到NSSA区域AR4的默认路由。原因在于NSSA区域的默认路由不会转发到内部区域。
所以需要AR3配置默认路由指向AR4，通过在AR3宣告默认路由，让内部路由器默认路由指向AR3，再由AR3转发AR4
[AR3]ip route-static 0.0.0.0 0.0.0.0 GigabitEthernet 0/0/0 10.1.34.4 [AR3]ospf [AR3-ospf-1]default-route-advertise always
<AR1>dis ospf lsdb OSPF Process 1 with Router ID 1.1.1.1 Link State Database Area: 0.0.0.0 Type LinkState ID AdvRouter Age Len Sequence Metric Router 2.2.2.2 2.2.2.2 482 60 80000009 10 Router 1.1.1.1 1.1.1.1 483 60 80000008 10 Router 3.3.3.3 3.3.3.3 459 60 8000000C 5 Network 10.1.23.3 3.3.3.3 487 32 80000001 0 Network 10.1.13.3 3.3.3.3 479 32 80000002 0 Network 10.1.12.2 2.2.2.2 484 32 80000001 0 Sum-Net 10.1.35.0 3.3.3.3 529 28 80000001 1 Sum-Net 10.1.34.0 3.3.3.3 459 28 80000002 1 Sum-Net 5.5.5.5 3.3.3.3 485 28 80000001 1 Sum-Net 4.4.4.4 3.3.3.3 417 28 80000001 1 AS External Database Type LinkState ID AdvRouter Age Len Sequence Metric External 0.0.0.0 3.3.3.3 76 36 80000001 1 External 202.102.1.0 3.3.3.3 391 36 80000001 1 <AR1>dis ospf lsdb ase 0.0.0.0 OSPF Process 1 with Router ID 1.1.1.1 Link State Database Type : External Ls id : 0.0.0.0 Adv rtr : 3.3.3.3 Ls age : 193 Len : 36 Options : E seq# : 80000001 chksum : 0x1380 Net mask : 0.0.0.0 TOS 0 Metric: 1 E type : 2 Forwarding Address : 10.1.34.4 Tag : 1 Priority : Low <AR1>dis ip routing-table 0.0.0.0 Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Routing Table : Public Summary Count : 1 Destination/Mask Proto Pre Cost Flags NextHop Interface 0.0.0.0/0 O_ASE 150 1 D 10.1.13.3 GigabitEthernet 0/0/1
查询AR1的LSDB和路由表已经学习到默认路由，此时还无法访问外部网络。
<AR1>ping -a 1.1.1.1 9.9.9.9
PING 9.9.9.9: 56 data bytes, press CTRL_C to break
Request time out
Request time out
Request time out
Request time out
Request time out
--- 9.9.9.9 ping statistics ---
5 packet(s) transmitted
0 packet(s) received
100.00% packet loss
此时AR4没有指向内部的路由，所以需要在AR4逐条配置指向内部网络的静态路由
[AR4]ip route-static 1.1.1.1 32 GigabitEthernet 0/0/0 10.1.34.3
<AR1>ping -a 1.1.1.1 9.9.9.9
PING 9.9.9.9: 56 data bytes, press CTRL_C to break
Reply from 9.9.9.9: bytes=56 Sequence=1 ttl=253 time=30 ms
Reply from 9.9.9.9: bytes=56 Sequence=2 ttl=253 time=30 ms
Reply from 9.9.9.9: bytes=56 Sequence=3 ttl=253 time=40 ms
Reply from 9.9.9.9: bytes=56 Sequence=4 ttl=253 time=30 ms
Reply from 9.9.9.9: bytes=56 Sequence=5 ttl=253 time=20 ms
--- 9.9.9.9 ping statistics ---
5 packet(s) transmitted
5 packet(s) received
0.00% packet loss
round-trip min/avg/max = 20/30/40 ms
<AR1>
AR4主体配置如下
interface GigabitEthernet0/0/0 ip address 10.1.34.4 255.255.255.0 # interface GigabitEthernet0/0/1 ip address 202.102.1.4 255.255.255.0 # interface GigabitEthernet0/0/2 # interface NULL0 # interface LoopBack0 ip address 4.4.4.4 255.255.255.255 # ospf 1 router-id 4.4.4.4 import-route direct area 0.0.0.1 network 4.4.4.4 0.0.0.0 network 10.1.34.4 0.0.0.0 nssa default-route-advertise # ip route-static 0.0.0.0 0.0.0.0 GigabitEthernet0/0/1 202.102.1.1 preference 5 ip route-static 1.1.1.1 255.255.255.255 GigabitEthernet0/0/0 10.1.34.3 # user-interface con 0 authentication-mode password idle-timeout 0 0
AR3主体配置如下：
interface LoopBack0 ip address 3.3.3.3 255.255.255.255 # ospf 1 router-id 3.3.3.3 default-route-advertise always area 0.0.0.0 network 3.3.3.3 0.0.0.0 network 10.1.13.3 0.0.0.0 network 10.1.23.3 0.0.0.0 area 0.0.0.1 network 10.1.34.3 0.0.0.0 nssa no-summary area 0.0.0.2 network 10.1.35.3 0.0.0.0 # ip route-static 0.0.0.0 0.0.0.0 GigabitEthernet0/0/0 10.1.34.4 # user-interface con 0 authentication-mode password idle-timeout 0 0
