200-301 · Question #719
When you enable PortFast on a switch port, the port immediately transitions to which state?
The correct answer is B. Forwarding. Enabling PortFast on a switch port causes it to bypass the normal Spanning Tree Protocol (STP) listening and learning states and transition directly to the forwarding state.
Question
Options
- ABlocking
- BForwarding
- CLearning
- DListening
How the community answered
(54 responses)- A7% (4)
- B87% (47)
- C2% (1)
- D4% (2)
Why each option
Enabling PortFast on a switch port causes it to bypass the normal Spanning Tree Protocol (STP) listening and learning states and transition directly to the forwarding state.
Blocking is an STP state where the port does not forward frames but listens for BPDUs, which PortFast aims to bypass.
PortFast immediately transitions a switch port to the forwarding state, skipping the listening and learning states, which reduces the time it takes for a device to gain network access.
Learning is an STP state where the port learns MAC addresses but does not forward frames, a state PortFast is designed to skip.
Listening is an STP state where the port listens for BPDUs but does not learn MAC addresses or forward frames, which PortFast also bypasses.
Concept tested: STP PortFast operation
Source: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12_2_55_se/configuration/guide/3750x_3560x_cg/swstp.html
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