CompTIA Network+ Practice Test

What is a subinterface?

1. A physical device connecting multiple networks

2. A virtual interface created from a physical interface

3. An external network configuration

4. A dedicated server interface

The correct answer is: A virtual interface created from a physical interface

A subinterface refers to a virtual interface that is created from a physical interface on a network device, such as a router or a switch. This allows a single physical interface to be divided into multiple logical interfaces, each of which can operate independently. Subinterfaces are commonly used in various scenarios, such as when conducting network segmentation, configuring virtual local area networks (VLANs), or implementing routing for different network segments without needing additional physical interfaces. For instance, in a situation where a router connects multiple VLANs, subinterfaces enable the router to manage traffic specific to each VLAN on a single physical interface. Each subinterface can be configured with its own IP address and routing settings, allowing for efficient traffic management and enhanced network flexibility. This understanding of subinterfaces is critical for network engineers and administrators, as it aids in optimizing network resource use and simplifies the network design by reducing the need for multiple physical connections.