（1）概念

子接口（Sub-Interface）是基于路由器以太网接口所创建的逻辑接口，以物理接口ID+子接口ID进行标识，子接口同物理接口一样可进行三层转发。

子接口不同于路由器的物理接口，可以终结携带VLAN Tag的数据帧。

基于一个物理接口创建多个子接口，将该物理接口对接到交换机的Trunk接口，即可实现使用一个物理接口为多个VLAN提供三层转发服务。

（2）子接口处理流程

（3）实验top

配置好PC1和PC2

S1的配置

<Huawei>system-view         

[Huawei]sysname S1

[S1]vlan batch 10 20

[S1]port-group 1

[S1-port-group-1]group-member GigabitEthernet 0/0/1 to GigabitEthernet 0/0/2

[S1-port-group-1]port link-type access

[S1-port-group-1]q

[S1]interface GigabitEthernet 0/0/1        

[S1-GigabitEthernet0/0/1]port default vlan 10

[S1-GigabitEthernet0/0/1]interface  GigabitEthernet 0/0/2

[S1-GigabitEthernet0/0/2]port default vlan 20

[S1-GigabitEthernet0/0/2]q

[S1]interface GigabitEthernet 0/0/3

[S1-GigabitEthernet0/0/3]port link-type trunk

[S1-GigabitEthernet0/0/3]port trunk allow-pass vlan all

[S1-GigabitEthernet0/0/3]q

[S1]q

<S1>save

The current configuration will be written to the device.

Are you sure to continue?[Y/N]y

Info: Please input the file name ( *.cfg, *.zip ) [vrpcfg.zip]:

Sep 14 2026 22:26:37-08:00 S1 %%01CFM/4/SAVE(l)[53]:The user chose Y when decidi

ng whether to save the configuration to the device.

Now saving the current configuration to the slot 0.

Save the configuration successfully.

AR1的配置

<Huawei>system-view

Enter system view, return user view with Ctrl+Z.        

[Huawei]sysname AR1

[AR1]interface GigabitEthernet 0/0/0.10

interface interface-type interface-number.sub-interface-number，该命令用来创建子接口，interface number代表物理接口的逻辑接口通道，一般情况下，子接口ID与所要终结的VLAN ID相同。

[AR1-GigabitEthernet0/0/0.10]dot1q termination vid 10

dot1q termination vid，该命令用来配置子接口dot1q终结的单层VLAN ID，默认情况下，子接口没有配置dot1q终结的单层VLAN ID。

[AR1-GigabitEthernet0/0/0.10]ip address 192.168.10.1 24

[AR1-GigabitEthernet0/0/0.10]arp broadcast enable

arp broadcast enable，该命令用来使能终结子接口的ARP广播功能。默认情况下，终结子接口没有使能ARP广播功能。如果没有启用，子接口就不能接收广播报文，就会直接丢弃。

[AR1-GigabitEthernet0/0/0.10]q

[AR1]interface GigabitEthernet 0/0/0.20

[AR1-GigabitEthernet0/0/0.20]dot1q termination vid 20

[AR1-GigabitEthernet0/0/0.20]ip address 192.168.20.1 24

[AR1-GigabitEthernet0/0/0.20]arp broadcast enable

[AR1-GigabitEthernet0/0/0.20]q

[AR1]q

<AR1>save

  The current configuration will be written to the device.

  Are you sure to continue? (y/n)[n]:y

  It will take several minutes to save configuration file, please wait…….

  Configuration file had been saved successfully

  Note: The configuration file will take effect after being activated

测试PC1 ping PC2