sw3-1：
vsf domain 10
vsf member 1
vsf port-group 1
vsf port-group int eth 1/0/27
vsf port-group int eth 1/0/28
exit
switch con mode vsf
sw3-2：
vsf domain 10
vsf member 2
vsf priority 32
vsf port-group 1
vsf port-group int eth 1/0/27
vsf port-group int eth 1/0/28
exit
switch con mode vsf
sw-core：
interface Vlan4000
vsf mad bfd enable
vsf mad ip address 10.10.255.253 255.255.255.252 member 1
vsf mad ip address 10.10.255.254 255.255.255.252 member 2
exit
vsf auto-merge enable
