- A
The LDP session is experiencing packet loss because the number of hellos sent and received are not equal.
Why wrong: Hellos sent 5000, received 4998; a small difference is normal due to timing.
- B
There is a problem with label distribution because label withdraw messages are significantly higher than label release messages.
Label withdraw (5) vs label release (2) suggests that some labels are being withdrawn but not released, which could indicate a problem.
- C
The router has sent 100 label mapping messages but received 95, indicating that 5 mapping messages were lost.
Why wrong: While true, this is a small difference and not necessarily a significant issue compared to the withdraw/release mismatch.
- D
The router has sent 1 notification message and received 2, indicating errors in the LDP session.
Why wrong: Notifications are normal for error reporting; a small number is not indicative of a major issue.
Quick Answer
The answer is a problem with label distribution, as indicated by the mismatch between label withdraw messages sent (5) and received (3) compared to label release messages sent (2) and received (1). In MPLS LDP, label withdraw messages signal that a label is no longer valid, while label release messages confirm the withdrawal was processed; a significant imbalance suggests that some withdrawals are not being acknowledged, pointing to packet loss or session instability. On the ENCOR 350-401 exam, this command tests your ability to interpret show mpls ldp traffic statistics and diagnose LDP session health, often appearing in troubleshooting scenarios where asymmetric counters reveal hidden issues. A common trap is focusing on the hellos or keepalive mismatches, but the real clue is the withdraw-to-release ratio, which indicates incomplete label cleanup. Remember the mnemonic: “Withdraws without releases mean the session has seizures.”
CCNP MPLS Practice Question
This 350-401 practice question tests your understanding of mpls. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network engineer runs the following command on Router R8:
R8# show mpls ldp traffic
LDP Traffic Statistics: Hellos sent: 5000, Hellos received: 4998 Initialization messages sent: 2, received: 2 Keepalive messages sent: 15000, received: 14995 Label mapping messages sent: 100, received: 95 Label withdraw messages sent: 5, received: 3 Label release messages sent: 2, received: 1 Label abort messages sent: 0, received: 0 Notification messages sent: 1, received: 2 Address messages sent: 10, received: 9 Address withdraw messages sent: 1, received: 0
Based on this output, what is a likely issue?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
There is a problem with label distribution because label withdraw messages are significantly higher than label release messages.
The statistics show a mismatch between sent and received messages for several types, especially label withdraw (5 sent, 3 received) and label release (2 sent, 1 received). This may indicate packet loss or a problem with the LDP session. However, the most notable discrepancy is in label mapping messages (100 sent, 95 received), suggesting some mapping messages were lost. But the question asks for a likely issue; the high number of label withdraws relative to releases could indicate instability.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The LDP session is experiencing packet loss because the number of hellos sent and received are not equal.
Why it's wrong here
Hellos sent 5000, received 4998; a small difference is normal due to timing.
- ✓
There is a problem with label distribution because label withdraw messages are significantly higher than label release messages.
Why this is correct
Label withdraw (5) vs label release (2) suggests that some labels are being withdrawn but not released, which could indicate a problem.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The router has sent 100 label mapping messages but received 95, indicating that 5 mapping messages were lost.
Why it's wrong here
While true, this is a small difference and not necessarily a significant issue compared to the withdraw/release mismatch.
- ✗
The router has sent 1 notification message and received 2, indicating errors in the LDP session.
Why it's wrong here
Notifications are normal for error reporting; a small number is not indicative of a major issue.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 350-401 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which 350-401 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Questions learners often ask
What does this 350-401 question test?
MPLS — This question tests MPLS — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: There is a problem with label distribution because label withdraw messages are significantly higher than label release messages. — The statistics show a mismatch between sent and received messages for several types, especially label withdraw (5 sent, 3 received) and label release (2 sent, 1 received). This may indicate packet loss or a problem with the LDP session. However, the most notable discrepancy is in label mapping messages (100 sent, 95 received), suggesting some mapping messages were lost. But the question asks for a likely issue; the high number of label withdraws relative to releases could indicate instability.
What should I do if I get this 350-401 question wrong?
Identify which 350-401 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 18, 2026
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.
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