三层交换：把带有部分路由功能的交换机配置三层接口地址，实现VLAN间的互通，三层交换机带有所有二层交换机的功能，在现实工作中三层交换的做法是最多的，可靠性高，扩展性好，带宽利用率高，速度快，配置简单等等。
一、实验环境：
1、准备两台PC和一台三层交换机华为S5700。
2、配置PC1的IP和网关地址，192.168.10.2/24，192.168.10.1，配置PC2的IP和网关地址，
192.168.20.1/24，192.168.20.1。
3、将交换机的g0/0/1和g0/0/2端口配置为Access模式，并把g0/0/1划到VLAN 10，把g0/0/2划到 VLAN 20
4、在三层交换机上配置各VLAN的网关，各VLAN的ID号必须与三层的VALNIF接口相对应。
二、一起看看具体配置吧
<Huawei>
<Huawei>sys
[Huawei]sysn
[Huawei]sysname L3SW1
[L3SW1]vlan bat 10 20
[L3SW1]int g0/0/1
[L3SW1-GigabitEthernet0/0/1]port li
[L3SW1-GigabitEthernet0/0/1]port link-t
[L3SW1-GigabitEthernet0/0/1]port link-type ac
[L3SW1-GigabitEthernet0/0/1]port link-type access
[L3SW1-GigabitEthernet0/0/1]port de
[L3SW1-GigabitEthernet0/0/1]port default
Sep 6 2020 20:45:05-08:00 L3SW1 DS/4/DATASYNC_CFGCHANGE:OID 1.3.6.1.4.1.2011.5.
25.191.3.1 configurations have been changed. The current change number is 6, the
change loop count is 0, and the maximum number of records is 4095.vlan 10
[L3SW1-GigabitEthernet0/0/1]int g0/0/2
[L3SW1-GigabitEthernet0/0/2]
[L3SW1-GigabitEthernet0/0/2]port link-t
[L3SW1-GigabitEthernet0/0/2]port link-type ac
[L3SW1-GigabitEthernet0/0/2]port link-type access
[L3SW1-GigabitEthernet0/0/2]port de
[L3SW1-GigabitEthernet0/0/2]port default
Sep 6 2020 20:45:25-08:00 L3SW1 DS/4/DATASYNC_CFGCHANGE:OID 1.3.6.1.4.1.2011.5.
25.191.3.1 configurations have been changed. The current change number is 8, the
change loop count is 0, and the maximum number of records is 4095.vlan 20
[L3SW1-GigabitEthernet0/0/2]q
[L3SW1]int int vlanif 10
[L3SW1-Vlanif10]ip add
[L3SW1-Vlanif10]ip address 192.168.10.1 24
[L3SW1-Vlanif10]
[L3SW1-Vlanif10]int vlanif 20
[L3SW1-Vlanif20]ip add
[L3SW1-Vlanif20]ip address 192.168.20.1 24
[L3SW1-Vlanif20]q