A Routed VLAN Interface (RVI) is created on a FortiSwitch when a physical port or a trunk is configured with an IP address, effectively converting it into a Layer 3 interface. During this process, FortiSwitch OS automatically assigns the interface to an internal, reserved VLAN, which is VLAN 4095. This dedicated VLAN is used internally by the switch to handle the Layer 3 routing functions for that specific port or trunk. The port is no longer a simple Layer 2 port and can participate in IP routing.

A. VLAN 1 is the default native VLAN for trunks, not a management VLAN automatically assigned when creating a specific Layer 3 routed port.

C. An RVI makes the port a Layer 3 interface. While it can be configured on a trunk, this statement incorrectly describes the primary function and effect of creating an RVI.

D. The port does become a Layer 3 interface, but the internal VLAN assigned for routing purposes is VLAN 4095, not VLAN 1.

1. Fortinet. (2024). FortiSwitch OS 7.6.0 Administration Guide. Fortinet Document Library. Page 129.

In the "Layer 3 > Routed VLAN interface" section, it states: "A routed VLAN interface (RVI) is a layer-3 interface that is automatically assigned to VLAN 4095. You can assign an IP address to an RVI and enable it for routing... When you configure an IP address on a physical port, the port becomes an RVI." This directly confirms that the port becomes a Layer 3 interface and is assigned to VLAN 4095.