In a layer 3 registration design, the registration VLAN's gateway relays DHCP requests to the FortiNAC-F interface that serves the registration network. In this topology, that is the FortiNAC-F registration-side interface (Port2).

FortiNAC-F serves as a central manager for security events originating from a diverse ecosystem of third-party security appliances, such as FortiGate, Check Point, and Cisco. Each vendor utilizes its own internal scale for severity levels within syslog messages (e.g., Check Point uses a
1? scale, while others may use 0?). To provide a consistent response regardless of the source, FortiNAC-F uses Severity Mappings to normalize these incoming values.
According to the FortiNAC-F Administration Guide, severity mappings allow the administrator to translate vendor-specific threat levels into standardized FortiNAC Security Levels (such as High, Medium, or Low Violation). When a syslog message arrives, the parser extracts the vendor's severity code, and the system immediately references the Security Event Severity Level Mappings table to determine how that event should be categorized internally. This normalization is vital because it allows a single Security Alarm to be configured to respond to any "High Violation" event, whether it was reported as a "Critical" by one vendor or a "Level 5" by another.
Without these mappings, the administrator would have to create separate, redundant security rules for every vendor to account for their different naming conventions and numerical scales.
"Each vendor defines its own severity levels for syslog messages. The following table shows the equivalent FortiNAC security level... To normalize these events, configure the Severity Level Mappings found in the device integration guides. This allows FortiNAC to generate a consistent security event that can then trigger an alarm regardless of the reporting vendor's specific terminology."

The N+1 High Availability (HA) architecture was introduced in FortiNAC-F version 7.6 to provide a more scalable and flexible redundancy model compared to the traditional 1+1 active/passive setup.
In an N+1 configuration, a single secondary (standby) appliance can provide coverage for multiple primary (active) Control and Application (CA) appliances.
To set up an N+1 HA cluster, there are two fundamental structural requirements:
A FortiNAC-F Manager (FortiNAC-M): Unlike standard 1+1 HA, which can be configured directly between two CAs, N+1 management is centralized. The FortiNAC-M acts as the orchestrator that manages the failover groups, monitors the health of the primaries, and coordinates the promotion of the secondary server if a primary fails.
A FortiNAC-F device designated as a Secondary: The cluster must have one appliance explicitly configured with the Secondary failover role. This device remains in a standby state, receiving database replications from all N primaries in its group until it is called upon to take over the functions of a failed unit