20
# Set the PVID of GigabitEthernet 1/0/2 to VLAN 100.
[SwitchA-GigabitEthernet1/0/2] port trunk pvid vlan 100
# Enable QinQ on GigabitEthernet1/0/2.
[SwitchA-GigabitEthernet1/0/2] qinq enable
[SwitchA-GigabitEthernet1/0/2] quit
# Configure the downlink port GigabitEthernet 1/0/3 as a trunk port, and assign the port to
VLANs 20 and 100.
[SwitchA] interface gigabitethernet 1/0/3
[SwitchA-GigabitEthernet1/0/3] port link-type trunk
[SwitchA-GigabitEthernet1/0/3] port trunk permit vlan 20 100
# Set the PVID of GigabitEthernet 1/0/3 to VLAN 100.
[SwitchA-GigabitEthernet1/0/3] port trunk pvid vlan 100
# Enable QinQ on GigabitEthernet 1/0/3.
[SwitchA-GigabitEthernet1/0/3] qinq enable
[SwitchA-GigabitEthernet1/0/3] quit
# Assign GigabitEthernet 1/0/2 and GigabitEthernet 1/0/3 to VLAN 100.
[SwitchA] vlan 100
[SwitchA-vlan100] port gigabitethernet 1/0/2
[SwitchA-vlan100] port gigabitethernet 1/0/3
4.
Configure Switch B:
# Create VLAN 10.
<SwitchB> system-view
[SwitchB] vlan 10
# Assign GigabitEthernet 1/0/2 to VLAN 10.
[SwitchB-vlan10] port gigabitethernet 1/0/2
[SwitchB-vlan10] quit
# Configure GigabitEthernet 1/0/1 as a trunk port, and assign the port to VLAN 10.
[SwitchB] interface gigabitethernet 1/0/1
[SwitchB-GigabitEthernet1/0/1] port link-type trunk
[SwitchB-GigabitEthernet1/0/1] port trunk permit vlan 10
5.
Configure Switch C:
# Create VLAN 20.
<SwitchC> system-view
[SwitchC] vlan 20
# Assign GigabitEthernet 1/0/2 to VLAN 20.
[SwitchC-vlan20] port gigabitethernet 1/0/2
[SwitchC-vlan20] quit
# Configure GigabitEthernet 1/0/1 as a trunk port, and assign the port to VLAN 20.
[SwitchC] interface gigabitethernet 1/0/1
[SwitchC-GigabitEthernet1/0/1] port link-type trunk
[SwitchC-GigabitEthernet1/0/1] port trunk permit vlan 20
Verifying the configuration
# Verify that DHCP client A and DHCP client B can obtain IP settings from Provider B. (Details not
shown.)