实验一

会配置OSPF下发默认路由，一般在出口设备配置下发默认路由，出口连接运营商，通过下发默认路由将数据引导至出口设备，再转交给运营商

拓扑

AR2模拟运营商

配置

PC1配置

LSW1配置

<Huawei>sys
[Huawei]sys LSW1
[LSW1]vlan batch 10 20
[LSW1]inte gi 0/0/2
[LSW1-GigabitEthernet0/0/2]port link-type access
[LSW1-GigabitEthernet0/0/2]port default vlan 10
[LSW1-GigabitEthernet0/0/2]inte gi 0/0/1
[LSW1-GigabitEthernet0/0/1]port link-type access
[LSW1-GigabitEthernet0/0/1]port default vlan 20
[LSW1-GigabitEthernet0/0/1]inte vlan 10
[LSW1-Vlanif10]ip addr 192.168.1.254 255.255.255.0
[LSW1-Vlanif10]inte vlan 20
[LSW1-Vlanif20]ip address 11.1.1.1 255.255.255.0
[LSW1-Vlanif20]q
[LSW1]ospf 1 router-id 2.2.2.2
[LSW1-ospf-1]area 0
[LSW1-ospf-1-area-0.0.0.0]network 11.1.1.1 0.0.0.0
[LSW1-ospf-1-area-0.0.0.0]network 192.168.1.0 0.0.0.255

AR1配置

<Huawei>sys
[Huawei]sys AR1
[AR1]inte gi 0/0/1
[AR1-GigabitEthernet0/0/1]ip addr 11.1.1.2 255.255.255.0
[AR1-GigabitEthernet0/0/1]inte gi 0/0/0
[AR1-GigabitEthernet0/0/0]ip addr 12.1.1.1 255.255.255.0
[AR1-GigabitEthernet0/0/0]inte lo 1
[AR1-LoopBack1]ip address 1.1.1.1 255.255.255.255
[AR1-LoopBack1]q
[AR1]ospf 1 router-id 1.1.1.1
[AR1-ospf-1]default-route-advertise   //下发默认路由，可选添加参数always，不添加always的时候只有当本设备有默认路由下会下发，没有则不发，加上always参数意思为不管本设备有无缺省路由都下发
[AR1-ospf-1]area 0
[AR1-ospf-1-area-0.0.0.0]network 11.1.1.2 0.0.0.0
[AR1-ospf-1-area-0.0.0.0]network 1.1.1.1 0.0.0.0
[AR1-ospf-1]q
[AR1]ip route-static 0.0.0.0 0 12.1.1.2

AR2配置

<Huawei>sys
[Huawei]sys AR2
[AR2]inte lo 1
[AR2-LoopBack1]ip addr 8.8.8.8 255.255.255.255
[AR2-LoopBack1]inte gi 0/0/0
[AR2-GigabitEthernet0/0/0]ip addr 12.1.1.2 255.255.255.0
[AR2]ip route-static 192.168.1.0 255.255.255.0 12.1.1.1   //现网中没有此步，运营商个内网回复使用的是nat技术，为了实验的完整性配置静态回程路由

通信验证

查看LSW1的路由表，可以看到OSPF下发的默认路由

[LSW1]dis ip routing-table 
Route Flags: R - relay, D - download to fib
\------------------------------------------------------------------------------
Routing Tables: Public
         Destinations : 8        Routes : 8        

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

        0.0.0.0/0   O_ASE   150  1           D   11.1.1.2        Vlanif20   //由AR1下发的默认路由
        1.1.1.1/32  OSPF    10   1           D   11.1.1.2        Vlanif20
       11.1.1.0/24  Direct  0    0           D   11.1.1.1        Vlanif20
       11.1.1.1/32  Direct  0    0           D   127.0.0.1       Vlanif20
      127.0.0.0/8   Direct  0    0           D   127.0.0.1       InLoopBack0
      127.0.0.1/32  Direct  0    0           D   127.0.0.1       InLoopBack0
    192.168.1.0/24  Direct  0    0           D   192.168.1.254   Vlanif10
  192.168.1.254/32  Direct  0    0           D   127.0.0.1       Vlanif10

PC1 ping 模拟运营商（AR2）

通信过程讲解