The correct answer is that the egress LSR removes the label before forwarding the IP packet, because in MPLS label operations, the egress router performs a pop to strip the final label, leaving only the native IP packet for onward routing. This contrasts with the ingress LSR, which performs a push to impose the initial label, and intermediate LSRs that execute a swap—replacing the incoming label with a new outgoing label. On the ENCOR 350-401 exam, this topic tests your understanding of the label lifecycle across the MPLS domain, often appearing in multiple-choice questions that require distinguishing which router performs which operation. A common trap is confusing the egress pop with the penultimate hop popping (PHP) feature, where the second-to-last router pops the label so the egress receives a pure IP packet. Remember the mnemonic: Ingress Pushes, Transit Swaps, Egress Pops—and PHP lets the penultimate do the pop early.
CCNP MPLS Practice Question
This 350-401 practice question tests your understanding of mpls. 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.
Which two statements about MPLS label operations are true? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The ingress LSR imposes a label onto the packet.
In MPLS, the ingress LSR imposes (pushes) a label onto the packet. At each intermediate LSR, the label is swapped (the incoming label is replaced with an outgoing label). The egress LSR removes (pops) the label before forwarding the IP packet. Penultimate Hop Popping (PHP) is a feature where the penultimate router pops the label, so the egress router receives only an IP packet. Option C is incorrect because the egress LSR always pops the label, not pushes. Option D is incorrect because label imposition occurs only at the ingress, not at every LSR. Option E is incorrect because label swapping is the action at transit LSRs, not label imposition.
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 ingress LSR imposes a label onto the packet.
Why this is correct
Correct because the ingress LSR pushes the initial label onto the packet.
Related concept
Read the scenario before looking for a memorised answer.
✓
The egress LSR removes the label before forwarding the IP packet.
Why this is correct
Correct because the egress LSR pops the label to restore the original IP packet.
Related concept
Read the scenario before looking for a memorised answer.
✗
The egress LSR pushes a new label onto the packet.
Why it's wrong here
Incorrect because the egress LSR pops the label, not pushes.
✗
Each LSR in the LSP performs label imposition.
Why it's wrong here
Incorrect because label imposition occurs only at the ingress LSR.
✗
Transit LSRs perform label imposition.
Why it's wrong here
Incorrect because transit LSRs perform label swapping, not imposition.
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.
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: The ingress LSR imposes a label onto the packet. — In MPLS, the ingress LSR imposes (pushes) a label onto the packet. At each intermediate LSR, the label is swapped (the incoming label is replaced with an outgoing label). The egress LSR removes (pops) the label before forwarding the IP packet. Penultimate Hop Popping (PHP) is a feature where the penultimate router pops the label, so the egress router receives only an IP packet. Option C is incorrect because the egress LSR always pops the label, not pushes. Option D is incorrect because label imposition occurs only at the ingress, not at every LSR. Option E is incorrect because label swapping is the action at transit LSRs, not label imposition.
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
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. Which two statements about MPLS label operations are true? (Choose two.)
medium
✓ A.The ingress LSR performs a label push operation.
✓ B.Transit LSRs perform a label swap operation.
C.The egress LSR performs a label push operation.
D.PHP (Penultimate Hop Popping) causes the egress LSR to pop the label.
E.The egress LSR always performs an IP lookup after label removal.
Why A: In MPLS, the ingress LSR pushes a label onto the packet, and transit LSRs swap the incoming label with an outgoing label based on the LFIB. PHP removes the label before the egress LSR, so the egress LSR does not perform a label lookup. The egress LSR forwards based on the IP header after label removal.
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Question Discussion
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