Question 1mediumdrag order
Read the full MPLS explanation →Question 1,286 of 2,015
Quick Answer
The answer is that the head-end signals a new LSP for restoration as the final step in MPLS Fast Reroute backup tunnel activation. This order is correct because MPLS FRR is designed for sub-50 millisecond traffic recovery: a backup tunnel is pre-configured to protect the primary LSP, and upon detecting a link or node failure—typically via BFD or an interface-down event—traffic is immediately switched to that backup tunnel. Only after this rapid local repair does the head-end router signal a new end-to-end LSP to restore the original path, ensuring minimal packet loss during the transition. On the ENCOR 350-401 exam, this drag-and-drop task tests your understanding that FRR prioritizes speed over optimization; a common trap is placing the new LSP signaling before the traffic switch, which would violate the “fast” in FRR. Remember the mnemonic “Protect, Detect, Switch, Signal”—the backup tunnel is pre-configured first, then failure is detected, traffic is switched locally, and finally the new LSP is signaled for full restoration.
350-401 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.
Drag and drop the steps of MPLS FRR (Fast Reroute) backup tunnel activation into the correct order, from first to last.
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"first"Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
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
✓
Pre-configure backup tunnel protecting primary LSP
MPLS FRR begins with pre-configuring backup tunnel, protecting the primary LSP, detecting link/node failure via BFD or interface down, switching traffic to backup tunnel, and then signaling a new LSP for restoration.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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: Pre-configure backup tunnel protecting primary LSP — MPLS FRR begins with pre-configuring backup tunnel, protecting the primary LSP, detecting link/node failure via BFD or interface down, switching traffic to backup tunnel, and then signaling a new LSP for restoration.
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.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
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 →
Same concept, more angles
1 more ways this is tested on 350-401
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. Drag and drop the steps of MPLS FRR (Fast Reroute) backup tunnel activation into the correct order, from first to last.
medium- ✓ A.Configure backup tunnel on PLR
- ✓ B.Merge backup tunnel with protected LSP
- ✓ C.Detect link or node failure
- ✓ D.PLR switches traffic to backup tunnel
- ✓ E.Revert traffic to primary LSP after repair
Why A: MPLS FRR begins with configuring the backup tunnel on the PLR. The PLR then merges the backup tunnel with the protected LSP. When a link or node failure is detected, the PLR immediately switches traffic to the backup tunnel. After the failure is repaired, traffic reverts to the primary LSP via make-before-break.
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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