What does a trunk link accomplish in networking?

A trunk link plays a crucial role in networking by carrying multiple VLANs' traffic across the same physical link. This functionality is essential within a switched network environment, particularly in scenarios where VLAN segmentation is implemented to improve performance and security.

In a typical network setup, VLANs are used to separate broadcast domains on the same network infrastructure. A trunk link allows switches to communicate and transmit frames belonging to different VLANs without needing separate physical links for each VLAN. This is accomplished by tagging the Ethernet frames with VLAN identifiers (such as using IEEE 802.1Q tagging), ensuring that the frames are appropriately routed to their respective VLANs once they reach a connected switch or device.

By enabling multiple VLANs to share a single link, trunk links help optimize network resources, reduce congestion, and simplify cable management while maintaining VLAN segmentation and improving overall network efficiency.