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N10-008 Exam - Question 143


A network technician reviews an entry on the syslog server and discovers the following message from a switch:

SPANNING-TREE Port 1/1 BLOCKED -

Which of the following describes the issue?

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Correct Answer: A

The message 'SPANNING-TREE Port 1/1 BLOCKED' indicates that the Spanning Tree Protocol (STP) detected a potential loop in the network and has taken action to prevent it by blocking the port. STP is designed to prevent network loops by dynamically blocking switch ports to ensure there is only one active path between network devices. Blocking a port is a standard procedure within STP to mitigate loops and maintain network stability.

Discussion

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JakeCharlesOption: A
Jan 30, 2023

A. A loop was discovered, and the impact was mitigated. The message "SPANNING-TREE Port 1/1 BLOCKED" indicates that a loop was discovered on port 1/1 and the spanning-tree protocol (STP) blocked the port to prevent the loop from causing a broadcast storm. The "BLOCKED" status is a normal part of the STP process, and it is used to prevent loops in the network. This is the most likely cause of the issue.

kungfusevenOption: A
Dec 11, 2022

A: Spanning Tree Protocol (STP) was developed to address these issues. STP ensures that there is only one logical path between all destinations on the network by intentionally blocking redundant paths that could cause a loop. A port is considered blocked when user data is prevented from entering or leaving that port

MitchFOption: A
Aug 15, 2023

GPT picks (A): "The message "SPANNING-TREE Port 1/1 BLOCKED" indicates that the issue is (A) a loop was discovered, and the impact was mitigated. In a spanning tree protocol (STP) environment, the "BLOCKED" status on a port means that the port is in a blocking state as part of STP's loop prevention mechanism. STP detects and prevents loops in Ethernet networks by selectively blocking certain ports to ensure there are no redundant paths that could lead to broadcast storms or network instability. When a loop is detected, STP will block one of the redundant paths to mitigate the loop and maintain network stability. Options (B) An incorrectly pinned cable being disconnected, (C) Incorrect link-local address, and (D) Port shut down are not directly related to the specific message indicating a blocked port due to a loop."

aeroangel1234
Oct 5, 2023

so when is it the right time to enable the port back up?

osmasterOption: A
Oct 13, 2023

A. A loop was discovered, and the impact was mitigated. In a network environment using the Spanning Tree Protocol (STP), when a port is in a "BLOCKED" state, it typically means that a loop or potential loop in the network topology has been detected, and STP has taken action to prevent the loop by blocking the port. STP's primary purpose is to prevent broadcast storms and network loops, and it does this by blocking redundant links that could introduce loops into the network.

phoenix98Option: A
Nov 7, 2023

spanning tree protocol (STP) Protocol that prevents layer 2 network loops by dynamically blocking switch ports as needed