PortFast Transition State

A

PortFast is a Cisco proprietary feature that is used to improve network performance and reduce the time required for a switch port to transition from the blocking state to the forwarding state. When PortFast is enabled on a switch port, it bypasses the Spanning Tree Protocol (STP) process and immediately transitions the port to the forwarding state.

The answer to the question is A. forwarding. When you enable PortFast on a switch port, the port immediately transitions to the forwarding state.

The normal process for a switch port to transition from the blocking state to the forwarding state involves several steps. When a port is first enabled or a link is re-established, the port goes through the following states:

1. Blocking: In this state, the switch port is listening to the network traffic and not forwarding any frames.

2. Listening: In this state, the switch port is preparing to forward frames by checking the network topology.

3. Learning: In this state, the switch port is learning the MAC addresses of devices connected to it.

4. Forwarding: In this state, the switch port is forwarding frames.

However, when PortFast is enabled on a switch port, the port immediately transitions to the forwarding state, bypassing the blocking, listening, and learning states. This is because PortFast assumes that the port is connected to an end device such as a computer, printer, or server, and there is no possibility of a loop in the network.

It is important to note that PortFast should only be enabled on access ports, not on trunk ports or ports connected to other switches. Enabling PortFast on these ports can cause loops in the network, which can lead to network outages and other problems.

In conclusion, when you enable PortFast on a switch port, the port immediately transitions to the forwarding state, bypassing the blocking, listening, and learning states.