In a networking context, what is the purpose of a trunk port?

A trunk port is used primarily to connect multiple VLANs (Virtual Local Area Networks) across networking devices. This functionality is crucial in networking environments where VLANs are implemented to segment traffic for improved performance, security, and management.

By enabling a trunk port, a single physical link can carry traffic from various VLANs simultaneously. This is achieved through tagging protocols like IEEE 802.1Q, which attach a tag to each Ethernet frame indicating the VLAN to which it belongs. As a result, devices (such as switches) can correctly interpret the incoming frames based on their tags and deliver them to the appropriate VLANs.

Connecting to a single VLAN is typically handled by access ports, which carry traffic for a specific VLAN without tagging. Isolating networks generally involves other networking devices or configurations rather than the specific role of trunk ports. While trunk ports can contribute to increased link capacity by aggregating multiple VLAN traffic, the primary purpose remains focused on enabling communication for multiple VLANs over a single connection.