What is the purpose of a trunk in networking?

A trunk in networking serves the specific purpose of carrying multiple VLANs across a single network connection. This is essential in environments where there is a need to manage different types of traffic for separate networks while still using a single physical network link. By utilizing trunking, network administrators can effectively consolidate traffic management and reduce the amount of physical infrastructure required since multiple virtual networks can coexist over the same link.

Implementing trunking allows tagged frames to travel over the trunk link, enabling the receiving switch to differentiate between the various VLANs based on the VLAN tags embedded in the frames. This solution is particularly beneficial in complex networks, as it supports scalability and simplifies the management of numerous VLANs.

The other choices, while relevant to various aspects of networking, do not define the specific role of a trunk. Limiting bandwidth usage pertains to different configurations aimed at traffic management rather than the fundamental function of a trunk. Enhancing network security is a broader goal that can be achieved through separate means, such as firewalls or access control lists, rather than the trunking mechanism itself. Increasing data transfer speed for individual devices involves separate techniques focused on optimizing network performance, which is not inherently a function of trunking either.