网络拓扑图：
需求：通过在核心交换机上部署VRRP + MSTP技术，实现网关冗余，核心SW1作为vlan 10的主网关，SW 2作为vlan 20的网关
SW3配置：
<Huawei>system-view [Huawei]undo info-center enable [Huawei]sysname SW3 [SW3]vlan batch 10 20 [SW3]interface gig0/0/3 [SW3-GigabitEthernet0/0/3]port link-type access [SW3-GigabitEthernet0/0/3]port default vlan 10 [SW3-GigabitEthernet0/0/3]inter gig0/0/4 [SW3-GigabitEthernet0/0/4]port link-type access [SW3-GigabitEthernet0/0/4]port default vlan 20 [SW3-GigabitEthernet0/0/4]quit [SW3]port-group group-member GigabitEthernet 0/0/1 to GigabitEthernet 0/0/2 [SW3-port-group]port link-type trunk [SW3-port-group]port trunk allow-pass vlan all