如图配置：
SW1 SW2 SW3 SW4组成一环型网络 Sw2 和Sw4个存在两业务vlan（vlan 10 和vlan 20）
1.Smart Link 组1 的引用实例1(绑定VLAN 10 )的流量从经过SW1 所在的链路相互通讯; 而Smart Link 组2 的引用实例2( 绑定VLAN20) 的流量从经过SW3 所在的链路相互通讯.
2.Smart Link 组1 和组2分别在VLAN 100和VLAN 200内发送和接收Flush报文。
3.当Sw1 和SW2之间的链路down时，SW4上的Smart-link组主动切换
Sw3 和Sw2 之间的链路down时，SW4上的Smart-link组主动切换
实验步骤：
1.交换网络中创建业务vlan 以及控制vlan
[SW1]vlan 10
[SW1]vlan 100
[SW1]vlan 20
[SW1]vlan 200
[SW2]vlan 10
[SW2]vlan 100
[SW2]vlan 20
[SW2]vlan 200
[SW3]vlan 10
[SW3]vlan 100
[SW3]vlan 20
[SW3]vlan 200
[SW4]vlan 10
[SW4]vlan 100
[SW4]vlan 20
[SW4]vlan 200
2.交换网络中接口放行所有vlan（业务vlan 以及控制vlan,不是all）
[SW1]vlan 10
[SW1-vlan10]port e0/4/2
[SW1]vlan 20
[SW1-vlan20]port e0/4/3
[SW1-Ethernet0/4/0]port link-type trunk
[SW1-Ethernet0/4/0]port trunk permit vlan 10 20 100 200
[SW1-Ethernet0/4/1]port link-type trunk
[SW1-Ethernet0/4/1]port trunk permit vlan 10 20 100 200
[SW2-Ethernet0/4/0]port trunk permit vlan 10 20 100 200
[SW2-Ethernet0/4/2]port trunk permit vlan 10 20 100 200
[SW3-Ethernet0/4/1]port trunk permit vlan 10 20 100 200
[SW3-Ethernet0/4/3]port trunk permit vlan 10 20 100 200
[SW4-vlan10]port e0/4/0
[SW4-vlan20]port e0/4/1
[SW4-Ethernet0/4/2]port trunk permit vlan 10 20 100 200
[SW4-Ethernet0/4/3]port trunk permit vlan 10 20 100 200
3.所有trunk接口关闭STP特性
[SW1-Ethernet0/4/1]undo stp
[SW1-Ethernet0/4/0]undo stp
[SW2-Ethernet0/4/0]undo stp
[SW2-Ethernet0/4/2]undo stp
[SW3-Ethernet0/4/1]undo stp
[SW3-Ethernet0/4/3]undo stp
[SW4-Ethernet0/4/2]undo stp
[SW4-Ethernet0/4/3]undo stp
4.在接入层交换机上创建MST域（创建vlan与实例的映射关系）
[SW1-mst-region]region-name cisco
[SW1-mst-region]instance 1 vlan 10
[SW1-mst-region]instance 2 vlan 20
[SW1-mst-region]active region-configuration
[SW4-mst-region]region-name cisco
[SW4-mst-region]instance 1 vlan 10
[SW4-mst-region]instance 2 vlan 20
[SW4-mst-region]active region-configuration
5.网络中所有tunk接口开启smart-link
flush 接口特征，并说明接收和发送flush报文时所使用的 控制vlan
[SW1-Ethernet0/4/0]smart-link flush enable control-vlan 100 200
[SW1-Ethernet0/4/1]smart-link flush enable control-vlan 100 200
[SW2-Ethernet0/4/0]smart-link flush enable control-vlan 100 200
[SW2-Ethernet0/4/2]smart-link flush enable control-vlan 100 200
[SW3-Ethernet0/4/2]smart-link flush enable control-vlan 100 200
[SW3-Ethernet0/4/1]smart-link flush enable control-vlan 100 200
[SW3-Ethernet0/4/3]smart-link flush enable control-vlan 100 200
[SW4-Ethernet0/4/3]smart-link flush enable control-vlan 100 200
[SW4-Ethernet0/4/2]smart-link flush enable control-vlan 100 200
6.在接入层交换机上创建smart-link
[SW1-smlk-group1]protected-vlan reference-instance 1
[SW1-smlk-group1]port e0/4/0 master
[SW1-smlk-group1]port e0/4/1 slave
[SW1-smlk-group2]protected-vlan reference-instance 2
[SW1-smlk-group2]port e0/4/1 master
[SW1-smlk-group2]port e0/4/0 slave
[SW1-smlk-group2]preemption mode role
[SW1-smlk-group1]preemption mode role
[SW4-smlk-group1]protected-vlan reference-instance 1
[SW4-smlk-group1]port e0/4/2 master
[SW4-smlk-group1]port e0/4/3 slave
[SW4-smlk-group1]preemption mode role
[SW4-smlk-group2]protected-vlan reference-instance 2
[SW4-smlk-group2]port e0/4/2 s
[SW4-smlk-group2]port e0/4/2 slave
[SW4-smlk-group2]port e0/4/3 m
[SW4-smlk-group2]port e0/4/3 master
[SW2-mtlk-group1]port E0/4/0 uplink
[SW2-mtlk-group1]port e0/4/2 downlink
[SW3-mtlk-group1]port e0/4/1 uplink
[SW3-mtlk-group1]port e0/4/3 downlink
7、测试
Shutdown SW1的E0/4/0，查看smart-link端口状态
激活链路，查看smart-link端口状态
