Fortinet NSE6_SDW_AD-7.6 Exam Dumps

In FortiOS (including FortiOS 7.6), FortiGate follows a strict and well-defined route lookup order when determining how to forward traffic. This order is critical for understanding SD-WAN behavior and is explicitly referenced in the FCSS SD-WAN curriculum.

The correct lookup sequence is:

Policy routes (Policy-Based Routing)

Policy routes are evaluated first. If traffic matches a policy route, FortiGate immediately forwards the traffic according to that policy and bypasses all other routing mechanisms.

Internet Service Database (ISDB) routes

If no policy route matches, FortiGate checks ISDB routes. These routes match traffic based on Internet Services rather than destination IP prefixes.

SD-WAN rules

If neither a policy route nor an ISDB route matches, FortiGate evaluates SD-WAN rules to determine the outgoing interface based on the configured SD-WAN strategy.

Routing table (connected, static, and dynamic routes such as BGP)

If no SD-WAN rule matches, FortiGate performs a normal routing table lookup.

FIB (Forwarding Information Base)

The FIB is used to forward the packet based on the selected route.

Drop

If no valid route exists, the packet is dropped.

Among the options provided, only Option D correctly reflects the beginning of this sequence by placing policy routes first, followed by ISDB routes, then SD-WAN rules, and finally static routes (representing the routing table).

Therefore, the correct answer is D.

The rule is in priority mode with HUB1-VPN1 (seq 4) as the first preferred member, HUB1-VPN2 second, and HUB1-VPN3 third. Latency itself does not cause HUB1-VPN3 to become preferred unless a higher-priority member fails SLA. If HUB1-VPN1's latency exceeds the SLA threshold (here simulated by latency reaching 200 ms), FortiGate stops using it and moves down the priority list. That is when HUB1-VPN3 could become the active path.

The described design is a multi-region SD-WAN architecture, where:

Each region has its own dual-hub ADVPN domain

Most traffic is intra-region

Inter-region traffic is limited and controlled

Spokes can be single-hub or dual-hub, depending on size and redundancy requirements

According to Fortinet's SD-WAN Architecture for Enterprise guidance, when deploying multiple ADVPN regions, eBGP is the recommended routing protocol between regions. Each region operates as an independent routing domain (typically iBGP within the region), while eBGP is used to exchange routes between regional hubs. This approach:

Prevents excessive route reflection and scaling issues

Provides clear administrative boundaries between regions

Improves stability and scalability in large global deployments

Matches the exact traffic pattern described (high intra-region, low inter-region traffic)

This is explicitly documented in Fortinet guidance for ''Using eBGP between regions with intra-region ADVPN'', which confirms that the architecture described in the question is valid and recommended when eBGP is used between regions.

Why the other options are incorrect:

Option B is incorrect because FortiOS does not impose a hard ''four-hub'' architectural limit in the described regional model. Each region has its own hubs, not a single flat multihub domain.

Option C is incomplete. While FortiManager Overlay Orchestrator can help operationally, it is not the key architectural requirement that makes this design valid. The question asks what makes the plan correct from a design standpoint, not a tooling standpoint.

Option D is incorrect because FortiOS fully supports mixed spoke connectivity within the same region (some spokes single-hub, others dual-hub), which is a common enterprise SD-WAN design.

Therefore, the correct and documented conclusion is that the plan is possible and eBGP should be used as the routing protocol between regions, which corresponds to Answer A.

From the SD-WAN monitor in FortiManager: 'The SD-WAN monitor provides a summary view of the branch devices and their members. In the scenario shown, it is clear that branch2_fgt is missing SLA configuration for one member, as evidenced by the lack of performance metrics. The monitor also shows only two branches in the current topology, allowing quick assessment of branch health and configuration completeness.' This kind of visibility is vital for proactive monitoring and rapid troubleshooting in SD-WAN environments. Reference:

[FCSS_SDW_AR-7.4 1-0.docx Q18]

FortiManager SD-WAN Monitoring Guide, ''Branch Device Health and SLA Status Visualization''