What is a VLAN?

A VLAN, or Virtual Local Area Network, is indeed best described as a logical grouping of devices within the same physical network. This means that VLANs allow network administrators to segment a single physical network into multiple isolated segments without the need for additional physical infrastructure. By utilizing VLANs, devices can be grouped together regardless of their physical location, facilitating better traffic management, security, and efficiency.

For instance, if a company has multiple departments (like HR, finance, and IT), VLANs can be used to create distinct broadcast domains and limit traffic to those specific groups. This setup enhances security by preventing unauthorized access between departments while still allowing devices to communicate as if they are on the same local network.

The other choices represent concepts that do not accurately define a VLAN. Aspects like dividing a network into physical segments pertain more to traditional network segmentation rather than the logical aspect of VLANs. Translating IP addresses to domain names refers to the Domain Name System (DNS), while protocols for ensuring reliable communication typically relate to transport layer protocols like TCP, which is not specific to VLAN functionality.