The correct answer is the egress LSR. This is determined by the outgoing tag being 'Pop tag', which means the router performs the final label operation by removing the MPLS label before forwarding the packet to the next hop as a standard IP packet. In MPLS forwarding table label operations, only the egress Label Switching Router (LSR) issues a pop instruction, while an ingress LSR would show 'No label' as its local tag, and a transit LSR would have a specific non-pop outgoing label. On the Cisco SPCOR / CCNP Service Provider Core 350-501 exam, this concept tests your ability to interpret MPLS label operations from a forwarding table, often appearing in scenario-based questions where a single label operation defines the router’s role. A common trap is confusing the egress LSR with the penultimate hop, but remember: the penultimate hop pushes an 'Untagged' or explicit-null label, not a 'Pop tag'. Memory tip: "Pop means drop—the egress is the last stop."
350-501 Networking Practice Question
This 350-501 practice question tests your understanding of networking. 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
show mpls forwarding-table 10.0.1.0/24
Local tag Outgoing tag Prefix Bytes tag switched Outgoing interface Next Hop
17 Pop tag 10.0.1.0/24 0 Gi0/1 192.168.2.1
Refer to the exhibit. What is the role of this router for prefix 10.0.1.0/24?
show mpls forwarding-table 10.0.1.0/24
Local tag Outgoing tag Prefix Bytes tag switched Outgoing interface Next Hop
17 Pop tag 10.0.1.0/24 0 Gi0/1 192.168.2.1
A
Transit LSR.
Why wrong: Transit LSR would swap labels, having a non-pop outgoing tag.
B
Egress LSR.
Egress LSR pops the outermost label, shown by 'Pop tag'.
C
Penultimate hop.
Why wrong: Penultimate hop would have 'Untagged' as outgoing tag, indicating PHP.
D
Ingress LSR.
Why wrong: Ingress LSR would have a local tag of 'No label' and outgoing tag assigned.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Egress LSR.
Option C is correct because the outgoing tag is 'Pop tag', indicating that the router removes the MPLS label before forwarding. This is the egress LSR. Option A (ingress) would have 'No label' as local tag. Option B (transit) would have a non-pop outgoing label. Option D (penultimate hop) would have 'Untagged' or a specific label.
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.
✗
Transit LSR.
Why it's wrong here
Transit LSR would swap labels, having a non-pop outgoing tag.
✓
Egress LSR.
Why this is correct
Egress LSR pops the outermost label, shown by 'Pop tag'.
Related concept
Read the scenario before looking for a memorised answer.
✗
Penultimate hop.
Why it's wrong here
Penultimate hop would have 'Untagged' as outgoing tag, indicating PHP.
✗
Ingress LSR.
Why it's wrong here
Ingress LSR would have a local tag of 'No label' and outgoing tag assigned.
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.
Networking — This question tests Networking — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Egress LSR. — Option C is correct because the outgoing tag is 'Pop tag', indicating that the router removes the MPLS label before forwarding. This is the egress LSR. Option A (ingress) would have 'No label' as local tag. Option B (transit) would have a non-pop outgoing label. Option D (penultimate hop) would have 'Untagged' or a specific label.
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. An engineer is troubleshooting MPLS forwarding. On a router, the 'show mpls forwarding-table' command displays that for a specific FEC, the outgoing label is 'Untagged'. What does this indicate?
easy
A.The label has been explicitly null.
✓ B.The router is the penultimate hop, performing PHP.
C.The router is the egress LSR.
D.The next-hop router does not support MPLS.
Why B: Option A is correct because 'Untagged' indicates that the router is performing Penultimate Hop Popping (PHP), meaning it will remove the MPLS label before forwarding to the egress router. Option B is incorrect because the egress LSR would typically show 'Pop Label' or the label itself. Option C is plausible but not standard; 'Untagged' does not indicate lack of MPLS support on the next-hop. Option D is incorrect because explicit null would show 'ExpNull'.
Last reviewed: Jun 24, 2026
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