вот конфиг который получился из примера:
/interface ethernet switch
set drop-if-invalid-or-src-port-not-member-of-vlan-on-ports=ether1,ether2,ether3
/interface ethernet switch egress-vlan-tag
add tagged-ports=ether1 vlan-id=20
add tagged-ports=ether1 vlan-id=30
add tagged-ports=switch1-cpu,ether1 vlan-id=99
/interface ethernet switch ingress-vlan-translation
add customer-vid=0 new-customer-vid=20 ports=ether2
add customer-vid=0 new-customer-vid=30 ports=ether3
add customer-vid=0 new-customer-vid=20 ports=ether2
add customer-vid=0 new-customer-vid=30 ports=ether3
/interface ethernet switch vlan
add ports=ether1,ether2 vlan-id=20
add ports=ether1,ether3 vlan-id=30
add ports=switch1-cpu,ether1 vlan-id=99