When a FortiSwitch operating in Layer 3 mode receives a packet, it first examines the destination IP address. The switch then performs a lookup in its hardware routing table, which is programmed by the forwarding information base (FIB). The FIB itself is populated by the control plane from configured static routes, connected interfaces, and dynamic routing protocols. If a matching route is found in the hardware table, the packet is forwarded out the corresponding interface at wire speed. If no match is found, the packet is dropped.

A. Hardware-based routing is offloaded to specialized ASICs for high-speed forwarding. The CPU's role is in the control plane, managing routing protocols and programming the hardware, not handling the actual packet forwarding.

B. ASIC hardware routing is not limited to dynamic routes. The hardware forwarding table is populated with all types of routes (static, connected, and dynamic) learned by the control plane.

D. This behavior describes a FortiSwitch operating as a Layer 2 extension in FortiLink mode. In standalone mode, a FortiSwitch is fully capable of making its own routing decisions locally.

1. Fortinet. (2024). FortiSwitchOS 7.6.0 Administration Guide (Standalone Mode). Fortinet Document Library. Page 121, "Routing" section.

The document states: "When a packet is received on an interface, the FortiSwitch unit gets the destination IP address. The FortiSwitch unit looks up the destination IP address in the hardware routing table and then the forwarding information base (FIB). If a matching entry is found, the FortiSwitch unit forwards the packet to the corresponding interface. If no matching entry is found, the FortiSwitch unit drops the packet." This directly supports the process described in answer C.