Which mode allows a Citrix ADC to control the packet-forwarding function based on route table lookups?

• A. MBF
• B. USIP
• C. Layer 2
• D. Layer 3

Answer: (D)

Routing decisions based on route table lookups happen at Layer 3. When the Citrix ADC operates in Layer 3 mode, it treats the device as a router: it examines the destination IP of each packet and uses the routing table to determine the next hop, enabling forwarding between different networks.

Layer 2 mode, by contrast, forwards based on MAC addresses and doesn’t consult IP routing tables. MBF and USIP are other forwarding approaches that optimize path handling but don’t inherently rely on per-packet route-table lookups in the way Layer 3 routing does. Because the scenario specifically describes using route tables to control forwarding, the Layer 3 mode is the correct match.