关于堆叠之间做bfd监测

创建一个单独的vlan，将bfd检测端口加入对应vlan，该端口和vlan不走业务。

# 创建VLAN 3，并将Device A上的端口GigabitEthernet1/0/1和Device B上的端口GigabitEthernet2/0/1加入VLAN3中。

<DeviceA> system-view

[DeviceA] vlan 3

[DeviceA-vlan3] port gigabitethernet 1/0/1 gigabitethernet 2/0/1

[DeviceA-vlan3] quit

# 创建VLAN接口3，并配置MAD IP地址。

[DeviceA] interface vlan-interface 3

[DeviceA-Vlan-interface3] mad bfd enable

[DeviceA-Vlan-interface3] mad ip address 192.168.2.1 24 member 1

[DeviceA-Vlan-interface3] mad ip address 192.168.2.2 24 member 2

[DeviceA-Vlan-interface3] quit

# 因为BFD MAD和生成树功能互斥，所以在GigabitEthernet1/0/1和GigabitEthernet2/0/1上关闭生成树协议。

[Sysname] interface gigabitethernet 1/0/1

[Sysname-gigabitethernet1/0/1] undo stp enable

[Sysname-gigabitethernet1/0/1] quit

[Sysname] interface gigabitethernet 2/0/1

[Sysname-gigabitethernet2/0/1] undo stp enable