The correct answer is that traffic is sent to wan2 because wan1 is considered dead. This happens because the SD-WAN lowest-cost algorithm SLA failure override logic prioritizes link health over cost; when wan1 fails the performance SLA due to 50% packet loss, it is marked as dead and removed from the active member pool, forcing traffic to the next lowest-cost member that is alive, which is wan2 with a cost of 20. On the Fortinet NSE 7 Advanced Security NSE7 exam, this scenario tests your understanding that the lowest-cost algorithm does not blindly follow cost—it first checks SLA compliance, and a common trap is assuming traffic would still use wan1 because its cost is lower. Remember the memory tip: "Dead members don't count cost"—if an interface fails its SLA, its cost is irrelevant, and the algorithm falls back to the next available lowest-cost link.
NSE7 Advanced Networking and SD-WAN Practice Question
This NSE7 practice question tests your understanding of advanced networking and sd-wan. 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 FortiGate with two WAN interfaces configured in an SD-WAN setup uses the 'lowest-cost' load balancing algorithm. The performance SLA monitors latency and jitter. If wan1 has a cost of 10 and wan2 has a cost of 20, but wan1 is experiencing 50% packet loss, what will happen to traffic?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Traffic is sent to wan2 because wan1 is considered dead
The 'lowest-cost' algorithm selects the member with the lowest cost. However, if a member fails the performance SLA (e.g., high packet loss), it is considered 'dead' and will not be used, even if its cost is lower. Traffic will then be sent to the next lowest-cost member that is alive.
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.
✗
Traffic is distributed equally between both links
Why it's wrong here
Lowest-cost does not distribute equally; it selects the best path.
✗
Traffic is dropped until wan1 recovers
Why it's wrong here
Traffic will be sent to the next available member.
✗
Traffic continues using wan1 because cost is lower
Why it's wrong here
If wan1 fails SLA, it is marked dead and not used.
✓
Traffic is sent to wan2 because wan1 is considered dead
Why this is correct
wan1 fails SLA so it's dead, traffic uses wan2.
Related concept
Read the scenario before looking for a memorised answer.
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 NSE7 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 NSE7 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.
Advanced Networking and SD-WAN — This question tests Advanced Networking and SD-WAN — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Traffic is sent to wan2 because wan1 is considered dead — The 'lowest-cost' algorithm selects the member with the lowest cost. However, if a member fails the performance SLA (e.g., high packet loss), it is considered 'dead' and will not be used, even if its cost is lower. Traffic will then be sent to the next lowest-cost member that is alive.
What should I do if I get this NSE7 question wrong?
Identify which NSE7 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. A FortiGate has two WAN interfaces (port1, port2) as SD-WAN members. The performance SLA monitor is configured for both with a latency threshold of 50 ms. The measured latency on port1 is 45 ms and on port2 is 55 ms. An SD-WAN rule uses 'lowest-cost' algorithm. Which interface will be selected for new sessions?
hard
✓ A.port1 because its latency is within threshold and lower than port2
B.port2 because port1's latency is close to threshold
C.The session is dropped
D.Both interfaces are used equally
Why A: Lowest-cost algorithm selects the member with the lowest cost, where cost is based on the performance SLA metric. Port1 has lower latency (45 ms < 55 ms) and is within threshold, so it has lower cost.
Last reviewed: Jun 21, 2026
Question Discussion
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This NSE7 practice question is part of Courseiva's free Fortinet 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 NSE7 exam.
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