FCSS_SDW_AR-7.6 FCSS - SD-WAN 7.6 Architect Questions and Answers

Rules template → Defines the SD-WAN rules for traffic steering.

BGP template → Configures dynamic routing for overlay tunnels.

IPsec tunnel template → Builds the IPsec VPN tunnels from the spoke to the hubs.

In the SD-WAN GUI, the absence of members in a zone is visually represented, and the Fortinet guide confirms:

" If a zone such as overlay-factories contains no members, it will be displayed as empty in the SD-WAN GUI. This may occur when the zone is reserved for future expansion, or if members have been temporarily removed for maintenance or reconfiguration. Traffic cannot be steered via an empty zone until at least one SD-WAN member is added. "

Such visual cues help operators quickly assess configuration status and readiness.

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 log shows messages on HUB1-VPN1 where the device processes a SHORTCUT_QUERY and performs NAT hole punching (peer at 192.2.0.1:4500). This indicates that the device is acting as a hub, helping two spokes (192.2.0.1 and 10.0.3.101) establish a direct ADVPN shortcut tunnel between each other, instead of routing their traffic through the hub.

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.

Your requirements map to two key MSSP goals described in the FCSS SD-WAN 7.6 blueprint patterns:

Delegate as much administration and management as possible to the MSSP This is best achieved when the hub security and SD-WAN control point is located on the MSSP premises , because the MSSP can centrally operate the core enforcement and overlay control. Both option B (dedicated hub at MSSP) and option D (shared hub at MSSP with customer isolation) meet this requirement.

Each site must maintain direct internet access (DIA) and be secure, with significant site-to-site traffic In Fortinet SD-WAN MSSP designs, spokes can still use local breakout for DIA while also building secure overlays for inter-site traffic. Placing the hub at the MSSP enables centralized security services and scalable inter-site connectivity management while preserving DIA where required. Options B and D support this operating model.

Why the other options do not best match:

A includes a dedicated hub on the customer premises , which reduces how much the MSSP can centralize and operate from its own environment, so it does not maximize delegation.

C places both hub and spokes on the customer premises . While the MSSP can manage using a dedicated ADOM, this blueprint does not align as strongly with “delegate installation and management” to the MSSP as the designs where the hub is hosted and operated from the MSSP premises.

Therefore, the two MSSP deployment blueprints that address your requirements are B and D .

In Fortinet SD-WAN, hubs should not have extensions like FortiSwitch, FortiAP, or FortiExtender installed, as these can affect hub functionality and scalability. While all device types can be included in the topology, the hubs must be " clean " FortiGate devices without such extensions to ensure proper ADVPN and overlay management.

The SD-WAN rule (config service edit 1) is configured with set mode priority. This means the rule selects the best interface based on a defined performance metric, as opposed to a simple static priority or SLA. The event log (image_41cfb5.png) shows Metric latency and Message Service prioritized by performance metric will be redirected in sequence order. This indicates that the rule is using latency to determine the preferred member. Given that the log message is about a change, and the most logical reason for a change in a priority mode is that a different member is now the best performer, it implies that the latency on port2 has become lower than that on port1.

The log message Service prioritized by performance metric will be redirected in sequence order confirms that FortiGate is changing the member being used for this service. Because the mode is priority, FortiGate dynamically selects the member that currently meets the best performance criteria, which in this case is latency. The log implies a new member has been selected as the most optimal, and with the default configuration, the members are sorted based on their performance, so the outgoing interface list is effectively updated to prefer the new best-performing member (port2).

Policy 3 points traffic To = HUB1-VPN1, which is an SD-WAN member interface. In SD-WAN you must reference the SD-WAN zone (the logical interface) in policies, not its member tunnels. Change the policy’s To interface to the zone HUB1, and the install will succeed.

The command shown in the exhibit is:

diagnose sys sdwan service 4 3

This command displays the runtime state of SD-WAN rule ID 3 on the device. The output explicitly shows:

Service(3) which confirms the SD-WAN rule being evaluated is rule number 3

Members(9) which indicates that nine SD-WAN members are associated with this rule

The listed members include multiple IPsec tunnel interfaces such as HUB1-VPN1 , HUB1-VPN2 , HUB1-VPN3 , HUB2-VPN1 , HUB2-VPN2 , and HUB2-VPN3 , which is characteristic of a spoke device connecting to multiple hubs in a hub-and-spoke ADVPN topology, as defined in the FCSS SD-WAN 7.6 architecture.

Option B is incorrect because, although members are listed under different interfaces, the output does not indicate SD-WAN zones. Zones are shown only in configuration output, not in this diagnostic command.

Option C is incorrect because this is not a hub device. The presence of multiple hub tunnels as SD-WAN members indicates a spoke role. Additionally, the output does not confirm the number of established ADVPN shortcuts.

Option D is incorrect because the output clearly references SD-WAN rule 3 , not rule 4, and it does not state that exactly three shortcut tunnels are allowed.

Therefore, the correct conclusion is that this is a spoke device and SD-WAN rule 3 is configured with nine members , which matches option A.

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.

The rule is in SLA mode with two SLAs. From the status, HUB1-VPN2 and HUB1-VPN3 meet the SLA (sla(0x2) and sla(0x3)), while HUB1-VPN1 does not (sla(0x0)). Among members that meet SLA, Forti Gate uses the configured order (priority-members 4 5 6) to pick the first eligible one—HUB1-VPN2—so traffic is routed over HUB1-VPN2.

This is because the setting minimum-sla-meet-members = 2 requires at least two SD-WAN zone members (in this case, HUB2-VPN1, HUB2-VPN2, and HUB2-VPN3) to pass the defined SLA health check (HUB1_HC) before the FortiGate will establish ADVPN shortcuts. If fewer than two members meet the SLA, shortcuts will not be created.

The exhibit shows the runtime details of two SD-WAN services (rules):

Service(2)

Mode(manual hash-mode=inbandwidth)

Members(2): port2 (WAN2), port1 (WAN1)

Application matching: Facebook, LinkedIn, Game

Source: 10.0.1.0–10.0.1.255 This rule is clearly intended for internet/DIA application steering and does not show a corporate destination range.

Service(3)

Mode(sla hash-mode=round-robin)

Members(6): HUB1-VPN1/2/3 and HUB2-VPN1/2/3

Source: 10.0.1.0–10.0.1.255

Destination: 10.0.0.0–10.255.255.255

Traffic from 10.0.1.124 to 10.0.0.254 matches Service(3) because the destination IP 10.0.0.254 falls within the destination range 10.0.0.0–10.255.255.255.

Within Service(3) , the member list shows SLA results per interface:

HUB1-VPN2 has sla(0x1) and num of pass(1)

HUB2-VPN2 has sla(0x2) and num of pass(1)

The remaining members (HUB1-VPN1, HUB2-VPN1, HUB1-VPN3, HUB2-VPN3) show sla(0x0) and num of pass(0)

This indicates that, for Service(3), only HUB1-VPN2 and HUB2-VPN2 are currently meeting the SLA requirements (passing), and because the rule uses hash-mode=round-robin, FortiGate load-balances sessions across the passing members.

Therefore, FortiGate will steer the traffic using HUB1-VPN2 or HUB2-VPN2 , which corresponds to Option B .

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.

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.

Hosting the hub at the MSSP centralizes installation, security, and ongoing management while each site (spoke) keeps local DIA. This can be done multi-tenant with a shared hub using a dedicated VDOM or with a fully dedicated hub per customer for stricter isolation and control, both meeting the requirement to delegate administration to the MSSP and support high inter-site traffic.

When using the diagnose sys session list command, SD-WAN-specific session steering is indicated by the presence of the sdwan_service_id field in the session data. This identifier ties the session directly to a specific SD-WAN rule or service. As noted in the Fortinet documentation: “Sessions that are handled according to SD-WAN rules will include a service ID tag (sdwan_service_id) in their session listing. This allows administrators to correlate live sessions with SD-WAN policy matches for troubleshooting and visibility.” This is a crucial diagnostic tool, as it distinguishes between traffic managed by traditional routing and that explicitly controlled by SD-WAN steering logic, aiding in operational insight and troubleshooting.

By default, local-out traffic does not use SD-WAN → FortiGate normally sends local-out traffic (e.g., DNS, NTP, FortiGuard updates) directly through its interfaces without applying SD-WAN rules.

You must configure each local-out feature individually to use SD-WAN → To steer local-out traffic via SD-WAN, you must explicitly configure the desired local-out features (e.g., DNS, FortiGuard, CAPWAP) to use SD-WAN rules.

The exhibit shows the following IPsec phase1-interface configuration applied on spoke tunnels :

set auto-discovery-shortcuts dependent

set network-overlay enable

set network-id < value >

In the FCSS SD-WAN 7.6 ADVPN architecture, the network-overlay and network-id parameters are used to logically group IPsec tunnels into separate overlays. When network-overlay is enabled , FortiGate treats the tunnel as part of an overlay network rather than a simple transport tunnel.

The network-id parameter is critical in multi-overlay ADVPN designs. Fortinet documentation specifies that ADVPN shortcuts are only allowed between tunnels that share the same network-id . This mechanism explicitly prevents cross-overlay shortcuts , ensuring that shortcuts are formed only within the same logical overlay and not across different overlays that may serve different purposes (for example, different hubs, regions, or transport groups).

The use of auto-discovery-shortcuts dependent further enforces correct shortcut behavior by ensuring that shortcut tunnels depend on the state of the parent overlay tunnel, but it does not by itself prevent multiple shortcuts or convert ADVPN versions.

Why the other options are incorrect:

Option A is incorrect because simply enabling network-overlay does not exist to “enable overlay links” in general; its purpose is to define overlay membership and control shortcut behavior.

Option B is incorrect because there is no concept of “ADVPN 2.0” conversion using these parameters in FortiOS 7.6.

Option D is incorrect because preventing multiple shortcuts over the same overlay is not controlled by network-id; multiple shortcuts within the same overlay are allowed when required.

Therefore, the valid objective of these settings is to prevent cross-overlay shortcuts , which corresponds to Option C .