NSE7 Advanced Networking and SD-WAN Practice Question
A company with a hub-and-spoke SD-WAN topology uses FortiGates at each site. The hub has two WAN links: MPLS (10 Mbps) and broadband (100 Mbps). The spokes connect only via MPLS. The company deploys a new real-time application that requires low latency and low jitter. The network administrator creates an SD-WAN rule for this application with 'best quality' strategy and both MPLS and broadband as members. The SLA for MPLS is configured with latency < 10 ms and jitter < 5 ms. The SLA for broadband is configured with latency < 50 ms and jitter < 20 ms. The actual measured latency on MPLS is 12 ms, and jitter is 4 ms. The broadband latency is 25 ms, jitter 10 ms. Which path will the application traffic take?
⚠ Common exam trap
Test-takers frequently assume MPLS is always preferred due to its lower latency profile, but the 'best quality' strategy strictly enforces SLA thresholds, and a link that fails its SLA is excluded from selection regardless of its absolute performance.
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
✓
The traffic will use the broadband link because MPLS SLA fails and broadband SLA is met.
The SD-WAN rule uses the 'best quality' strategy, which selects the member with the best SLA performance. The MPLS link fails its SLA because its measured latency of 12 ms exceeds the configured threshold of 10 ms, even though jitter is within limits. The broadband link meets both its latency (25 ms < 50 ms) and jitter (10 ms < 20 ms) thresholds, so it becomes the active path for the application traffic.
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 traffic will use the broadband link because MPLS SLA fails and broadband SLA is met.
Why this is correct
Broadband satisfies its configured SLA thresholds (25 ms latency, 10 ms jitter, both within 50 ms and 20 ms), while MPLS breaches its latency SLA at 12 ms against the 10 ms limit. FortiGate's best quality strategy selects the member meeting its SLA, so traffic fails over to broadband despite MPLS's lower measured latency.
- ✗
The traffic will be load-balanced between MPLS and broadband.
Why it's wrong here
Load balancing requires the 'load balance' strategy, which distributes sessions across members without SLA scoring. Under 'best quality', FortiOS selects the single member with the best SLA compliance, so traffic follows one path rather than being shared across MPLS and broadband.
- ✗
The traffic will use the MPLS link because it is the preferred member.
Why it's wrong here
MPLS fails its own SLA: measured 12 ms latency breaches the configured 10 ms threshold, so 'best quality' excludes it regardless of preference. Preferred-member ordering applies to the 'manual' strategy, where an administrator ranks members explicitly and no SLA comparison decides the path.
- ✗
The traffic will be dropped because no link meets the SLA.
Why it's wrong here
Traffic is not dropped: FortiOS SD-WAN evaluates each member against its own SLA, and broadband's measured 25 ms latency and 10 ms jitter both satisfy its configured thresholds, so a viable path exists. Dropping occurs only when every member fails its SLA, or when the rule enforces a strict SLA action with no compliant link.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.