After executing the displayinterface Ethernet 1/0/1 command on the switch SWA, the output information is as follows:

After executing the displayinterface Ethernet 1/0/1 command on the switch SWA, the output information is as follows:

[SWA]display interface Ethernet 1/0/1

Ethernetl/0/1 current state: UP

PVID: 10

Mdi type: auto

Link delay is 0(sec)

Port link-type: trunk

VLAN passing: 1 (default vlan), 10

VLAN permitted: 1 (default vlan), 2-4094

Trunk port encapsulation: IEEE 802.1q

Port priority: 0

It can be judged from the above output
A . Port Ethernet1/0/1 is a Trunk port, allowing all VLAN data to pass through
B . Data frames with VLAN1 tags will be stripped of tags when they leave port Ethernet1/0/1
C . Data frames with VLAN20 tags can be forwarded from port Ethernet1/0/1
D . Data frames with VLAN10 tags will not be discarded when entering port Ethernet1/0/1