What is the role of a trunk port in VLANs?

The role of a trunk port in VLANs is to carry traffic for multiple VLANs between switches. This is essential in a network setup where multiple VLANs are configured, as it allows different types of traffic to flow over a single physical link while keeping the data logically separated.

Trunk ports use tagging protocols, such as IEEE 802.1Q, to mark packets with information about which VLAN they belong to. This ensures that when data travels across the trunk link, it can be delivered to the appropriate VLAN on the receiving switch, maintaining network segmentation and improving security and performance.

In contrast, other roles mentioned, such as isolating traffic from different VLANs or connecting devices within a single VLAN, do not pertain to trunk ports. Instead, these tasks are typically handled by access ports, which connect end devices to a specific VLAN, thereby not mixing traffic from multiple VLANs. Additionally, routing functions are managed by routers or layer 3 switches, rather than trunk ports themselves.