The correct answer is that the 'Pop Label' entry signifies penultimate hop popping (PHP) in MPLS. This is because in a PHP configuration, the penultimate router (the router just before the egress LSR) removes the top MPLS label from the packet before forwarding it to the egress router. The egress router then only needs to perform a simple IP lookup on the remaining payload, reducing its processing burden. On the Cisco SPCOR 350-501 exam, this concept tests your understanding of MPLS label operations and forwarding behavior; a common trap is confusing PHP with explicit null labels (label 0), but remember that PHP uses the implicit null label (label 3) to signal the penultimate hop to pop. A solid memory tip: "Pop before you drop" — the penultimate hop pops the label so the egress router doesn't have to drop it.
350-501 Architecture Practice Question
This 350-501 practice question tests your understanding of architecture. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Exhibit
PE1#show mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
16 Pop Label 10.0.0.0/8 0 Gi0/0/0 192.168.1.1
17 34 10.0.1.0/24 0 Gi0/0/1 192.168.1.2
18 Untagged 10.0.2.0/24 0 Gi0/0/2 192.168.1.3
Refer to the exhibit. What is the significance of the entry with 'Pop Label'?
PE1#show mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
16 Pop Label 10.0.0.0/8 0 Gi0/0/0 192.168.1.1
17 34 10.0.1.0/24 0 Gi0/0/1 192.168.1.2
18 Untagged 10.0.2.0/24 0 Gi0/0/2 192.168.1.3
A
It indicates a merge operation
Why wrong: Merge is not indicated by Pop Label.
B
It indicates the penultimate hop popping (PHP)
PHP removes the label before sending to the egress.
C
It indicates the label is removed at this router
Why wrong: Actually the label is popped before forwarding, so it is removed here, but the term PHP is more precise. However, technically it is removed, but the best answer is PHP.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
It indicates the penultimate hop popping (PHP)
The 'Pop Label' in the outgoing label column indicates that the router will pop the top label before forwarding (penultimate hop popping, PHP). This is typical for PHP in MPLS.
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.
✗
It indicates a merge operation
Why it's wrong here
Merge is not indicated by Pop Label.
✓
It indicates the penultimate hop popping (PHP)
Why this is correct
PHP removes the label before sending to the egress.
Related concept
Read the scenario before looking for a memorised answer.
✗
It indicates the label is removed at this router
Why it's wrong here
Actually the label is popped before forwarding, so it is removed here, but the term PHP is more precise. However, technically it is removed, but the best answer is PHP.
✗
It indicates an error
Why it's wrong here
Pop Label is normal in PHP.
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 350-501 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 350-501 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.
Architecture — This question tests Architecture — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: It indicates the penultimate hop popping (PHP) — The 'Pop Label' in the outgoing label column indicates that the router will pop the top label before forwarding (penultimate hop popping, PHP). This is typical for PHP in MPLS.
What should I do if I get this 350-501 question wrong?
Identify which 350-501 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
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Refer to the exhibit. The router has an outgoing label of 'Pop' for prefix ***********. What does this imply?
medium
A.The router has not learned a label for that prefix
B.The router will not forward traffic for that prefix
✓ C.The router is the penultimate hop and will remove the label before forwarding
D.The router will push a new label for that prefix
Why C: A 'Pop' outgoing label indicates that the router is the penultimate hop and advertises implicit null. Option D is correct. Option A is wrong because Pop means the label is removed. Option B is wrong because the outgoing interface is still used. Option C is wrong because Pop is not a failure.
Last reviewed: Jun 24, 2026
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This 350-501 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 350-501 exam.
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