On access switch ASW4, port Gi0/7 connects an IP phone, and a workstation is plugged into the pass-through port on the back of that phone. The desk requires the workstation in data VLAN 41 and the phone in voice VLAN 42. The port is configured as a single access port with both an access VLAN and a voice VLAN assigned. Which statements correctly describe how ASW4 handles traffic on this one physical port? Select THREE.
- AThe workstation's frames are forwarded untagged on the access link and are placed by ASW4 into data VLAN 41. Correct
- BThe IP phone tags its own voice frames with VLAN 42, which the switch learns and signals to the phone through CDP or LLDP-MED. Correct
- CA single access port can carry the untagged data VLAN and the tagged voice VLAN at the same time without being a full trunk. Correct
- DASW4 must be set to switchport mode trunk on Gi0/7 before the phone and workstation can use their separate VLANs.
- EThe phone's voice frames cross ASW4 untagged and are sorted into VLAN 42 by inspecting their source MAC address.
Why A is correct: On a port with an access VLAN plus a voice VLAN, the attached PC stays untagged and the switch classifies that traffic into the configured access VLAN, here VLAN 41.
Why B is correct: The voice VLAN feature instructs the phone via CDP or LLDP-MED to tag voice traffic with the voice VLAN id, so the phone marks its frames with VLAN 42.
Why C is correct: The voice VLAN is a special case that lets one access port carry untagged data plus tagged voice, so a general 802.1Q trunk is not required for this phone-and-PC topology.
Why D is wrong: Forcing a trunk seems necessary because two VLANs cross the port, but the voice VLAN feature works on an access port, and a trunk would change how the PC traffic is classified.
Why E is wrong: This is tempting because data is untagged, but voice frames are explicitly 802.1Q tagged with the voice VLAN and are not classified from the source MAC address.