CompTIA Network+ Practice Test

How does a switch create and update its MAC address table?

1. By listening for VLAN requests

2. By examining incoming traffic and noting source MAC addresses

3. By receiving ARP broadcasts from devices

4. By querying a central database

The correct answer is: By examining incoming traffic and noting source MAC addresses

A switch creates and updates its MAC address table primarily by examining incoming traffic and noting the source MAC addresses of the frames it receives. When a switch receives a data frame, it checks the source MAC address of that frame and records it in its MAC address table along with the corresponding port from which the frame was received. This process allows the switch to learn which devices are connected to which ports, enabling it to efficiently forward frames only to the appropriate ports rather than broadcasting them to all connected devices. This method of learning is crucial for the switch's operation because it helps reduce unnecessary traffic on the network and improves overall efficiency. Each time a new frame arrives, the switch continually updates its MAC address table, ensuring that it maintains a current view of the network's topology. While other options mention methods like listening for VLAN requests or receiving ARP broadcasts, these actions do not directly contribute to the learning process of MAC addresses by the switch. VLAN requests pertain more to network segmentation and management, while ARP broadcasts are part of the IP address resolution process and are not the primary mechanism by which switches learn MAC addresses. Querying a central database would not apply in the context of traditional switching operations, as switches are designed to operate independently without needing to rely on a