What is the duration of the Listening state when STP is enabled?

The duration of the Listening state when Spanning Tree Protocol (STP) is enabled is 15 seconds. In this state, a switch listens for Bridge Protocol Data Units (BPDUs) to learn about the network topology without yet participating in frame forwarding. The purpose of this period is to allow time for the switch to gather information about other switches in the network, ensuring that it can make informed decisions regarding the bridging paths.

This listening interval is crucial for maintaining the stability and integrity of the network, helping to prevent loops by ensuring that all switches are aware of the current topology before moving to the next state. The 15-second duration is specified in the IEEE 802.1D standard which outlines the operation of STP, demonstrating how the protocol is designed to create a loop-free network environment.