What Step Follows a Top-to-Bottom OSI Model Examination in CompTIA Troubleshooting?

N10-009 By islever Editorial Last updated

Short answer

A Test the theory.

Question

Which of the following steps in the troubleshooting methodology comes after using a top-to-bottom examination of the OSI model to determine cause?
  1. Test the theory. Correct Answer
  2. Establish a plan of action.
  3. Verify full system functionality.
  4. Identify the problem.

Key Takeaways

This question tests your knowledge of the exact order of CompTIA's troubleshooting steps, and the trap is misreading 'determine cause' as step 3 when the OSI model examination actually occurs in step 2, 'Establish a theory of probable cause.'

In CompTIA Network+ troubleshooting, a top-to-bottom OSI model review is used to establish a theory of probable cause, making 'Test the theory' the immediate next step. The community consensus favors option A, with 67 votes, and this aligns with the official troubleshooting methodology.

Common mistake: The most common wrong answer is B, 'Establish a plan of action,' because some test-takers interpret 'determine cause' as the completion of step 3. However, the top-to-bottom OSI examination is used to build a theory, so the correct next step is to test that theory.

Expert Analysis

Why the Answer Is Correct

In the CompTIA troubleshooting methodology, step 2 is 'Establish a theory of probable cause.' Using the OSI model from top to bottom is a technique included in this step to help isolate the layer most likely causing the issue. Once that theory has been formed, the next step is exactly 'Test the theory to determine cause.' Therefore, the sequence is: identify problem → establish theory via OSI examination → test theory. Option A is the correct immediate next step.

Why the Other Options Are Wrong

B ('Establish a plan of action') comes only after the theory has been tested and the cause confirmed, so choosing it skips the required testing step. C ('Verify full system functionality') is part of the later verification phase after implementing a solution. D ('Identify the problem') is the first step and would already have been completed before a technician begins an OSI model examination. Thus, A is the only answer that maintains the correct troubleshooting order.

Community Comment Notes

Several comments correctly note that a top-to-bottom OSI examination is used to establish a probable cause, followed by testing that theory. Comment [2] lists the steps and confirms that after step 2 you move to step 3. Some comments, such as [5] and [6], argue for B by focusing on the phrase 'to determine cause,' but they overlook that the OSI model analysis belongs to step 2, not step 3. The majority vote and the most-liked explanations support A.

Official Reference

https://www.comptia.org/certifications/network

This link opens the official vendor documentation in a new tab.

Exam Strategy

Memorize the exact order of the troubleshooting methodology: Identify the problem, Establish a theory, Test the theory, Establish a plan, Implement, Verify, Document. When a question mentions the OSI model top-to-bottom approach, recognize that it is part of establishing a theory, and the next step is always to test that theory.

Community Votes

A
77%
B
23%

77% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 9 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 9

  1. CalicoJack 👍 4 Answered A
    You should be able to establish a theory using the OSI model, that is its intended use after all. Test the theory is next.
  2. ExamLSMotor 👍 3 Answered A
    The steps are: 1. Identify the problem 2. Establish a theory of probable cause 3. Test the theory 4. Implement a solution or escalate 5. Verify functionality 6. Document findings After step 2 we move on to 3, "test the theory". A is the correct answer.
  3. CISUMPATR 👍 2 Answered A
    Correct answer is A because, examination of the OSI Model simply means "Establish a Theory of Probable Cause" according to Comptia, indicating the next step to be test the theory
  4. 93831b0 👍 1 Answered B
    Using a top-to-bottom examination of the OSI model to determine the cause of the issue happens during the "Test the theory to determine cause" step. So, the next step is to establish a plan of action. Why are the other options incorrect? - Test the theory: You've already tested the theory (using the OSI model examination) and determined the cause. - Verify full system functionality: This is a later step, after you've implemented a solution. - Identify the problem: This is the first step, which has already been completed.
  5. Knekworst 👍 1
    This one pisses me off. The CompTIA troubleshooting methodology references to the OSI is to vague! This is why these exams are predatory. I would Select. B Comptia references by checking the OSI-model during ''3. Test the Theory'' What comes after Test the Theory? ''Establish a plan of action'' So... the right answer is: B: Establish a plan of action. Reference: https://www.comptia.org/blog/troubleshooting-methodology
Show 4 more comments
  1. Philco 👍 1 Answered D
    Test the Theory --------- comes in as the 3rd step of the Troubleshooting mdel and I believe, after examining the top-to-Bottom of the OSI. We should start with step 1..........ID the Problem
  2. fc040c7 👍 1 Answered A
    Top to bottom involves analyzing each layer of the network model to identify the potential source of the problem and creating a theory. So then next step would be to test the theory
  3. Philco 👍 1 Answered D
    my understanding is that after top-to-bottom examination, NO problem ID has been made yet.So,.....1st step of Troubleshooting Model is, "Identify the Problem"
  4. TDWA2k 👍 2 Answered B
    Establish a plan of action.

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