1.實驗拓撲

2.使用設備

eNSP模擬建議下行設備三臺使用S3700模擬（全部使用S5700可能會出現流量丟失等異常問題。）

3.實驗配置

[SW1]dis cu
#
sysname SW1
#
vlan batch 100 110
#
interface Ethernet0/0/1port link-type accessport default vlan 100
#
interface GigabitEthernet0/0/1port link-type trunkport trunk allow-pass vlan 100 110stp disable
#
interface GigabitEthernet0/0/2port link-type trunkport trunk allow-pass vlan 100 110stp disable
#
smart-link group 1restore enablesmart-link enableport GigabitEthernet0/0/1 masterport GigabitEthernet0/0/2 slavetimer wtr 30flush send control-vlan 110
#

[SW2]dis cu
#
sysname SW2
#
vlan batch 100 110
#
interface GigabitEthernet0/0/1shutdownport link-type trunkport trunk allow-pass vlan 100 110stp disablesmart-link flush receive control-vlan 110
#
interface GigabitEthernet0/0/2port link-type trunkport trunk allow-pass vlan 100 110stp disablesmart-link flush receive control-vlan 110
#
monitor-link group 1port GigabitEthernet0/0/2 uplinkport GigabitEthernet0/0/1 downlink 1timer recover-time 10
#

[SW3]dis cu
#
sysname SW3
#
vlan batch 100 110
#
interface GigabitEthernet0/0/1port link-type trunkport trunk allow-pass vlan 100 110stp disablesmart-link flush receive control-vlan 110
#
interface GigabitEthernet0/0/2port link-type trunkport trunk allow-pass vlan 100 110stp disablesmart-link flush receive control-vlan 110
#
monitor-link group 1port GigabitEthernet0/0/1 uplinkport GigabitEthernet0/0/2 downlink 1timer recover-time 10
#

[SW4]dis cu
#
sysname SW4
#
vlan batch 100 110
#
interface Vlanif100ip address 192.168.100.254 255.255.255.0
#
interface GigabitEthernet0/0/1port link-type trunkport trunk allow-pass vlan 100 110stp disablesmart-link flush receive control-vlan 110
#
interface GigabitEthernet0/0/2port link-type trunkport trunk allow-pass vlan 100 110stp disablesmart-link flush receive control-vlan 110
#

4.實驗現象

此處表示流量走向如下圖所示

此時將SW2的上行鏈路關閉

[SW2-GigabitEthernet0/0/2]shutdown?

此時流量走向