子网重叠测试

子网重叠的两个网络可以相互通

虽然子网掩码不同，但是 R1 可以 ping R2：

<R1>ping 10.0.12.14
  PING 10.0.12.14: 56  data bytes, press CTRL_C to break
    Reply from 10.0.12.14: bytes=56 Sequence=1 ttl=255 time=50 ms
    Reply from 10.0.12.14: bytes=56 Sequence=2 ttl=255 time=30 ms
    Reply from 10.0.12.14: bytes=56 Sequence=3 ttl=255 time=30 ms
    Reply from 10.0.12.14: bytes=56 Sequence=4 ttl=255 time=40 ms
    Reply from 10.0.12.14: bytes=56 Sequence=5 ttl=255 time=60 ms

  --- 10.0.12.14 ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 30/42/60 ms

当配置完接口 IP 后，查看路由表可以发现多了条路由：
比如：

<R1>display ip routing-table 
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
         Destinations : 4        Routes : 4        

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

       10.0.0.0/16  Direct  0    0           D   10.0.12.13      Ethernet0/0/0

根据 R1 这条 routing table 中的第一个条目，配置 dst IP 是同一个子网。因为是直连的情况，所以 nexthop 直接发送。R2 回包也是同理。

以下是 R2 的相关信息：

[Huawei-Ethernet0/0/0]ping 10.0.12.13
  PING 10.0.12.13: 56  data bytes, press CTRL_C to break
    Reply from 10.0.12.13: bytes=56 Sequence=1 ttl=255 time=40 ms
    Reply from 10.0.12.13: bytes=56 Sequence=2 ttl=255 time=40 ms
    Reply from 10.0.12.13: bytes=56 Sequence=3 ttl=255 time=50 ms
    Reply from 10.0.12.13: bytes=56 Sequence=4 ttl=255 time=40 ms
    Reply from 10.0.12.13: bytes=56 Sequence=5 ttl=255 time=30 ms

[Huawei-Ethernet0/0/0]display arp
IP ADDRESS      MAC ADDRESS     EXPIRE(M) TYPE        INTERFACE   VPN-INSTANCE 
                                          VLAN/CEVLAN PVC                      
------------------------------------------------------------------------------
10.0.12.14      5489-98e6-4c16            I -         Eth0/0/0
10.0.12.13      5489-98d2-47cf  20        D-0         Eth0/0/0
------------------------------------------------------------------------------
Total:2         Dynamic:1       Static:0     Interface:1    

[Huawei-Ethernet0/0/0]display ip routing-table 
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
         Destinations : 4        Routes : 4        

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

     10.0.12.12/30  Direct  0    0           D   10.0.12.14      Ethernet0/0/0
     10.0.12.14/32  Direct  0    0           D   127.0.0.1       Ethernet0/0/0
      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