What is the primary purpose of VLANs in a network?

The primary purpose of VLANs, or Virtual Local Area Networks, is to split up broadcast domains. In a traditional network, a single broadcast domain encompasses all devices on the same physical network segment, meaning that broadcast packets are sent to all devices within that domain, regardless of whether they need to receive the information. This can lead to unnecessary traffic and performance issues.

By implementing VLANs, network administrators can logically segregate networks without altering the physical setup. Each VLAN acts as an independent broadcast domain, meaning that broadcasts sent in one VLAN do not affect devices in another VLAN. This segmentation helps to improve overall network efficiency; it reduces broadcast traffic and enhances security by isolating sensitive data or devices from other parts of the network.

The other options, while related to networking, do not accurately capture the primary function of VLANs. Increasing physical connections pertains to hardware infrastructure rather than logical segmentation. Enhancing routing protocols is related to how routes are managed between different networks rather than addressing the broadcast traffic issue within a local network. Lastly, while VLANs can contribute to network security by isolating segments, their main role lies in controlling broadcast domains. Thus, the correct choice emphasizes VLANs' fundamental purpose in network design.