FCSS_SDW_AR-7.4 Fortinet FCSS - SD-WAN 7.4 Architect Free Practice Exam Questions (2025 Updated)

For SD-WAN deployments that span multiple regions—where most traffic is intra-region and there is no requirement for inter-region ADVPN—the best practice is to use IBGP with BGP on loopback interfaces for routing within each region and EBGP between the regions. This approach ensures robust and scalable routing, isolates regional routing domains, and enables policy control at region boundaries. BGP on loopback is preferred for its reliability and flexibility, as it enables peering that is not tied to specific physical interfaces. EBGP between regions allows each region to maintain independent routing policies and summarization, optimizing performance and manageability. By separating IBGP (intra-region) and EBGP (inter-region), you create a modular architecture that scales easily and simplifies fault isolation and troubleshooting.

The SD-WAN load balancing algorithm selection is nuanced. Fortinet documentation states:

"Outbandwidth hash mode can be used with any load balancing strategy that permits multiple simultaneous paths. However, SD-WAN load balancing in practice is only enabled when the strategy is either 'best quality' or 'lowest cost (SLA)'. Manual strategies do not support automated load balancing, and are typically used for deterministic or failover scenarios."

Selecting the correct strategy is key for achieving desired distribution and redundancy.

Before FortiGate can steer traffic according to SD-WAN rules, certain configuration elements must be present. The guide states:

"SD-WAN is not a standalone feature and interacts with several fundamental FortiGate configurations. Specifically, you must: (1) Define the interfaces (physical, VLAN, or IPsec) that will act as SD-WAN members, (2) Create firewall policies to allow traffic to be steered by SD-WAN, and (3) Set up routing so that traffic has valid routes via SD-WAN members. Without these, SD-WAN rules will not be able to match or steer any traffic."

Security profiles and traffic shaping are not mandatory for basic SD-WAN steering but can be layered on for enhanced security and QoS once foundational elements are present.

Traffic steering in Fortinet SD-WAN is based on defined rules and the corresponding outgoing interfaces. The exhibit (not shown here) would indicate that the traffic from the LAN subnet 10.0.1.0/24 to the server 10.2.5.254 is matched by SD-WAN rule 3 and sent out via the HUB1-VPN3 interface.

The implicit SD-WAN rule serves as the final catch-all. Per Fortinet:

"Sessions matching the implicit SD-WAN rule do not have an SD-WAN service id, as they are not associated with any specific user-defined SD-WAN rule. Additionally, this occurs only when traffic fails to match any entry in the policy route table. This default handling guarantees connectivity while minimizing the risk of blackholed traffic."

Administrators can observe this in diagnostic outputs for troubleshooting.

To allow spokes in different hub-and-spoke groups to establish ADVPN shortcuts, the hubs must be configured to forward and send ADVPN shortcut offers. The key required settings on the hub are auto-discovery-forwarder (for VPNs to hubs) and auto-discovery-sender (for VPNs to spokes). This ensures the hub can facilitate and advertise ADVPN shortcut offers between spokes.

SD-WAN performance SLAs and health checks are typically measured using synthetic probes (e.g., ping, HTTP, TCP). In the configuration shown, the health/performance metrics are tied specifically to TCP traffic related to Facebook and YouTube applications. According to the SD-WAN 7.4 Concept Guide: “When application-based performance measurement is enabled, only TCP flows matching the specified application IDs (such as Facebook and YouTube) are used to calculate metrics. The performance metric for the member is then computed as an average of those application-specific probes or traffic samples.” This enables fine-grained, application-aware steering and ensures that measured values reflect the real user experience for critical business applications.

When the member priority of a port is increased (e.g., port2 to 20), FortiGate evaluates existing sessions and applies “dirty” flags where applicable. The SD-WAN session management mechanism is described in detail: “Upon a change in SD-WAN member priority, all existing sessions using that member are marked as dirty. For SNAT sessions, the gateway information is updated to ensure future packets are routed through the newly preferred member, in this case, port1. This automatic re-evaluation allows SD-WAN to dynamically respond to topology or priority changes, maintaining optimal routing.” This is fundamental to seamless failover and session persistence in Fortinet SD-WAN, ensuring active flows are redirected based on updated priorities or health status.

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.

When referencing a zone in a static route, FortiGate’s behavior is described as:

"Referencing a zone in a static route causes FortiGate to install a static route for each member interface of the zone. This enables ECMP (Equal-Cost Multi-Path) and load balancing where supported and ensures that traffic can be steered over any valid zone member according to SD-WAN rules or standard routing."

This mechanism is fundamental to Fortinet’s implementation of SD-WAN and simplifies large, multi-interface deployments.