The correct configuration is to set the manual strategy with MPLS as the first member and enable the SLA check. This works because a manual strategy with ordered members evaluates each link in sequence; the SD-WAN rule first attempts the MPLS link, and only if the SLA fails—meaning the link does not meet the defined performance thresholds for voice traffic—does it automatically fail over to the next member, typically the broadband link. On the Fortinet NSE 4 exam, this scenario tests your understanding of SD-WAN rule strategies and SLA-based failover, often appearing as a configuration question where you must distinguish between manual, best-quality, and load-balance strategies. A common trap is assuming that simply listing MPLS first without enabling the SLA check will enforce the failover, but without the SLA, the rule will not dynamically switch when the link degrades. Remember the memory tip: “Manual means ordered, SLA means conditional—first link if healthy, failover if not.”
NSE4 High Availability and Diagnostics Practice Question
This NSE4 practice question tests your understanding of high availability and diagnostics. 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.
An SD-WAN rule is configured with a 'manual' strategy and multiple members. The engineer wants to ensure that voice traffic always uses the MPLS link as long as it meets the SLA, otherwise use the broadband link. Which configuration is required?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "always"
Why it matters: Absolute qualifier. An answer using 'always' is only correct if there are genuinely no exceptions — absolute statements are often wrong in networking.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Set the manual strategy with MPLS as first member and enable SLA check.
Option B is correct because a manual strategy with ordered members and an SLA check allows the SD-WAN rule to first attempt the MPLS link; if the SLA is met, traffic uses MPLS, and if the SLA fails, the rule automatically fails over to the next member (broadband). This directly implements the engineer's requirement of 'MPLS if SLA met, otherwise broadband.'
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.
✗
Set the strategy to 'volume' and configure MPLS as preferred.
Why it's wrong here
Incorrect; volume strategy is for load balancing, not failover.
✓
Set the manual strategy with MPLS as first member and enable SLA check.
Why this is correct
Correct; manual strategy with SLA check will use the first member if SLA is met, otherwise the next.
Clue confirmation
The clue word "always" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use 'load balancing' strategy and assign MPLS a higher weight.
Why it's wrong here
Incorrect; weight does not guarantee exclusive use.
✗
Set the strategy to 'best quality' and set MPLS with highest priority.
Why it's wrong here
Incorrect; best quality uses dynamic metrics, not fixed priority.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse 'manual strategy' with 'best quality' strategy, assuming 'best quality' will always pick MPLS, but 'best quality' dynamically selects the best-performing link at any moment, which may not be MPLS if broadband has better SLA metrics.
Detailed technical explanation
How to think about this question
In FortiGate SD-WAN, a manual strategy with SLA check uses the configured member order as a priority list: the first member is always attempted first, and traffic is only moved to the next member if the SLA target (e.g., latency, jitter, packet loss) is not met. This is implemented via the 'set strategy manual' command combined with 'set sla-check enable' on the SD-WAN rule, which triggers health-check probes to each member. In real-world deployments, this ensures voice traffic (sensitive to jitter and latency) consistently uses the MPLS link when its SLA is acceptable, while broadband acts as a backup without requiring manual intervention.
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.
TExam Day Tips
→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 NSE4 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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
High Availability and Diagnostics — This question tests High Availability and Diagnostics — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set the manual strategy with MPLS as first member and enable SLA check. — Option B is correct because a manual strategy with ordered members and an SLA check allows the SD-WAN rule to first attempt the MPLS link; if the SLA is met, traffic uses MPLS, and if the SLA fails, the rule automatically fails over to the next member (broadband). This directly implements the engineer's requirement of 'MPLS if SLA met, otherwise broadband.'
What should I do if I get this NSE4 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "always". Absolute qualifier. An answer using 'always' is only correct if there are genuinely no exceptions — absolute statements are often wrong in networking.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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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 network engineer is configuring SD-WAN on a FortiGate with two WAN links: MPLS (port1) and Internet (port2). The MPLS link has lower latency and jitter. The engineer wants to route all VoIP traffic (SIP and RTP) over the MPLS link unless it is unavailable. Which SD-WAN rule configuration should be used?
medium
A.Create an SD-WAN rule for VoIP traffic with strategy 'best quality' and set the SLA target for latency to 10ms on the MPLS link.
B.Create an SD-WAN rule for VoIP traffic with strategy 'load balancing' and assign equal weight to both links.
✓ C.Create an SD-WAN rule for VoIP traffic with strategy 'manual' or 'prefer' and select MPLS as the preferred member, with Internet as backup.
D.Create an SD-WAN rule for VoIP traffic with strategy 'best quality' and set the SLA target to prefer the Internet link.
Why C: Option C is correct because the engineer requires a deterministic routing policy where VoIP traffic always uses the MPLS link unless it fails. The 'manual' (or 'prefer') strategy in SD-WAN rules allows you to explicitly set a preferred member (MPLS) and designate the other link (Internet) as a backup, ensuring failover only when the preferred link is unavailable. This matches the requirement of routing all VoIP traffic over MPLS unless it is unavailable, without relying on SLA performance metrics.
Last reviewed: Jun 11, 2026
Question Discussion
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This NSE4 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 NSE4 exam.
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