What is a trunk port?

• A. Switch port connecting to a single VLAN only.
• B. A port used only for management.
• C. Switch port carrying multiple VLANs using tagging (802.1Q).
• D. Wireless uplink.

Answer: (C)

A trunk port is a switch port configured to carry traffic for multiple VLANs over a single physical link by tagging each frame with its VLAN identifier (commonly using 802.1Q). This tagging lets the receiving device know which VLAN the frame belongs to, enabling multiple VLANs to share one connection—ideal for inter-switch links and uplinks that need to carry several networks. In contrast, an access port carries traffic for only one VLAN and typically sends/receives untagged frames. A port used solely for management is a management port, not defined by VLAN tagging. A wireless uplink serves a wireless access point rather than carrying VLAN-tagged traffic. So the description of a switch port carrying multiple VLANs using tagging best captures what a trunk port is.