What is a trunk link used for?

A trunk link is specifically designed to carry traffic from multiple virtual LANs (VLANs) over a single physical connection between devices such as switches or routers. This capability allows for efficient use of network resources and reduces the physical cabling needed in a network environment. By utilizing tagging protocols such as IEEE 802.1Q, trunk links can differentiate between VLAN traffic, ensuring that data for each VLAN is preserved and managed correctly as it traverses the trunk link.

While connecting more than two switches can use trunk links, it is not the primary function of a trunk link. Similarly, enabling protocols like Spanning Tree Protocol (STP) serves a separate purpose in preventing loops in networks but does not define what a trunk link does. The encapsulation of Layer 2 frames is a function that may occur over trunk links, but it does not inherently describe the use or purpose of the trunk itself. Thus, the primary role of a trunk link is its ability to handle traffic from multiple VLANs simultaneously.