Which state does the switch port move to when PortFast is enabled?
When PortFast is enabled on a switch port, the switch port moves directly from the blocking state to the forwarding state, skipping the listening and learning states.
The blocking state is the initial state of a switch port when it is first enabled. In this state, the port does not forward data frames and simply listens to the network for 20 seconds. This prevents network loops and ensures that the Spanning Tree Protocol (STP) has enough time to calculate the topology of the network.
After the blocking state, the port moves to the listening state. In this state, the port starts to learn about the network topology by receiving BPDUs (Bridge Protocol Data Units) from neighboring switches. This state lasts for 15 seconds.
Following the listening state, the port enters the learning state. In this state, the port continues to receive BPDUs and begins to learn the MAC addresses of devices on the network by analyzing the source MAC addresses of incoming frames. This state lasts for another 15 seconds.
Finally, after the learning state, the port enters the forwarding state. In this state, the port starts to forward data frames and becomes fully operational. When PortFast is enabled, the port skips the listening and learning states and moves directly to the forwarding state.
PortFast is typically enabled on access ports, where end-user devices are connected, to reduce the amount of time it takes for a port to become operational. This helps to improve network performance and reduce user frustration.