Cisco Enterprise Network Core Technologies (ENCOR) Practice Exam

In the Learning state of the Spanning Tree Protocol (STP), a port is primarily focused on building and updating the MAC address table. During this state, the switch is not yet forwarding traffic but is actively listening to incoming frames. This allows the switch to learn the source MAC addresses of the frames it receives and store them in its MAC address table.

When a switch learns a source MAC address from a device connected to a port, it associates that MAC address with the specific port from which the frame was received. This process is crucial for efficient forwarding decisions to be made once the port transitions to the Forwarding state.

The other options outlined do not accurately describe the Learning state. For instance, while ports do not forward traffic during this state, they are not involved in blocking traffic to prevent loops, as that occurs in the Blocking state. Additionally, they do not reset forwarding decisions during the Learning state; instead, they are gathering the information necessary for making those decisions in the future.