On a switch, how are frames typically treated on access ports versus trunk ports in terms of tagging?

• A. Trunk ports do not forward frames.
• B. Access ports send untagged frames; trunk ports send tagged frames for all VLANs except the native VLAN which is untagged.
• C. Both port types always tag frames.
• D. Access ports tag frames; trunk ports do not tag.

Answer: (B)

VLAN tagging defines how frames are carried across switch links. Access ports are tied to a single VLAN and always send and receive untagged frames. Trunk ports carry traffic for multiple VLANs using 802.1Q tagging, so frames from most VLANs are tagged when they traverse the trunk, with the exception of the native VLAN, which is sent untagged. This means the correct statement is that access ports send untagged frames, while trunk ports send tagged frames for all VLANs except the native VLAN, which remains untagged. The other options conflict with how tagging works on these port types: trunk ports do forward frames and include tags; access ports do not tag frames; and both port types do not always tag frames.