SW1:
<SW1>sys
[SW1] vlan batch10 20
[SW1] interface g0/0/1
[SW1-GigabitEthernet0/0/1] portlink-type trunk
[SW1-GigabitEthernet0/0/1] port trunkallow-pass vlan 10 20
[SW1-GigabitEthernet0/0/1] intergi0/0/2
[SW1-GigabitEthernet0/0/2] portlink-type trunk
[SW1-GigabitEthernet0/0/2] port trunkallow-pass vlan 10 20
SW2:
<SW2>sys
[SW2]vlan batch10 20
[SW2] interfaceg0/0/24
[SW2-GigabitEthernet0/0/24] portlink-type trunk
[SW2-GigabitEthernet0/0/24] port trunkallow-pass vlan 10 20
[SW2-GigabitEthernet0/0/24]inter gi0/0/1
[SW2-GigabitEthernet0/0/1]port link-type access
[SW2-GigabitEthernet0/0/1] port defaultvlan 10
[SW2-GigabitEthernet0/0/1]inter gi0/0/2
[SW2-GigabitEthernet0/0/2]port link-type access
[SW2-GigabitEthernet0/0/2]port default vlan 20
SW3:
<SW3>sys
[SW3]vlan batch10 20
[SW3] interfaceg0/0/24
[SW3-GigabitEthernet0/0/24] portlink-type trunk
[SW3-GigabitEthernet0/0/24] port trunkallow-pass vlan 10 20
[SW3-GigabitEthernet0/0/24]inter gi0/0/1
[SW3-GigabitEthernet0/0/1]port link-type access
[SW3-GigabitEthernet0/0/1] port defaultvlan 20
[SW3-GigabitEthernet0/0/1]inter gi0/0/2
[SW3-GigabitEthernet0/0/2]port link-type access
[SW3-GigabitEthernet0/0/2]port default vlan 10