FCSS_SDW_AR-7.4 Exam Dumps - FCSS - SD-WAN 7.4 Architect

The FortiManager SD-WAN overlay template preview, as described in the document, indicates:

"When the device is acting as a hub, the configuration enables the sending of ADVPN shortcut offers to spokes. This means the hub can facilitate on-demand dynamic shortcut tunnel creation between spokes, improving performance for branch-to-branch communication by bypassing the hub for inter-branch traffic after initial discovery."

Such a role is critical in scalable ADVPN topologies, enabling hub devices to optimize overlays dynamically.

Specify the gateway of the SD-WAN member port1 with an IP address or use the default value → The error log shows invalid ip – prop[gateway]: ip4class(${sdwan_port1_gw}) invalid ip addr, meaning the variable ${sdwan_port1_gw} does not have a valid mapping. Assigning a valid IP address or default value for the gateway resolves this error.

Review the per-device mapping configuration for metadata variables → The issue is tied to how the metadata variable ${sdwan_port1_gw} is mapped for branch1_fgt. If this device does not have the variable properly defined in per-device mapping, the configuration will fail. Correcting the mapping ensures that the install works.

The provisioning templates in FortiManager are designed for flexible, scalable configuration of large SD-WAN deployments. The official documentation explains:

"Template groups can consist of both system and SD-WAN templates, providing a way to apply consistent settings across multiple devices. CLI templates are evaluated and executed in order from top to bottom within the template group, which is crucial for managing dependencies. Furthermore, CLI template groups can contain both regular CLI templates and advanced (Perl-script-based) templates, allowing complex or conditional configuration logic."

This modular design streamlines large deployments by separating system, SD-WAN, and CLI logic into reusable building blocks.

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.

Event logs (from the exhibit) show how traffic is matched to SD-WAN rules and routed. The log output indicates that voice traffic is being routed through the HUB1-VPN3 tunnel. This matches SD-WAN's application-aware steering, which uses dynamic performance metrics to select the optimal path.

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.

Enforce Device Configuration is enabled and the blueprint applies the provisioning CLI templates. The LAN-interface script sets port1 and port2 to DHCP and assigns a static IP to port5 (using the branch_id variable). Therefore, when FortiManager pushes the blueprint, it updates the configurations of port1, port2, and port5 - and their IP addresses may change accordingly.

The line sdwan_mbr_seq=1 sdwan_service_id=4 indicates that this session is part of an SD-WAN rule. sdwan_service_id=4 confirms that the session is being handled by SD-WAN rule ID 4. This directly links the flow to the SD-WAN configuration.

The line no_offload_reason: redir-to-ips denied-by-nturbo shows that the session is not offloaded to the NPU (Network Processing Unit) and is being processed by the main CPU. A session that is not offloaded can be re-evaluated. If the outgoing interface (the one currently being used) goes down, the FortiGate will re-evaluate the session against the SD-WAN rules to find a new active member to steer the traffic through. This is a fundamental behavior of SD-WAN, which ensures network resilience.