What is the purpose of a trunk port in switching?

A trunk port serves an important role in networking by carrying traffic for multiple VLANs (Virtual Local Area Networks) between switches. This functionality allows a single physical connection to handle the data traffic of various VLANs, which enhances network efficiency and reduces the number of required physical connections.

Trunk ports utilize tagging protocols, such as IEEE 802.1Q, to differentiate between the VLANs, ensuring that the data packets can be properly directed to their respective VLANs as they travel across the trunk link. This capability is vital in environments where network segmentation is necessary for different departments or services, as it helps maintain organization and security within the network without the need for additional infrastructure.

The other options presented do not accurately describe the primary purpose of trunk ports. For instance, while a trunk port plays a role in connecting devices, it is specifically designed for VLAN traffic management rather than direct connections to end devices. Similarly, rather than isolating broadcast domains, trunk ports facilitate the carrying of VLAN traffic across broadcast domains. Moreover, while they can be part of a connection to routers, their main purpose is not limited to such functions but rather centers on multiple VLAN support in a switching environment.