Which term describes a network design in which inter-VLAN routing is performed by a router using a single physical interface with sub-interfaces?

Which term describes a network design in which inter-VLAN routing is performed by a router using a single physical interface with sub-interfaces?

• A. Router on a Stick
• B. Layer 3 Switch
• C. Sticky MAC
• D. BPDU Guard

Answer: (A)

The main idea being tested is inter-VLAN routing using a single router interface with multiple sub-interfaces. In this design, the link between the switch and the router is a trunk, carrying multiple VLANs. On the router, each sub-interface represents a different VLAN and uses 802.1Q encapsulation, with its own IP address that serves as the default gateway for hosts in that VLAN. The router then routes traffic between those VLANs through these sub-interfaces, all over one physical connection. This arrangement is known as router on a stick. This differs from a Layer 3 Switch approach, where inter-VLAN routing happens on the switch itself using SVIs and internal routing. The other terms—Sticky MAC and BPDU Guard—pertain to security and spanning-tree protections, not to how inter-VLAN routing is implemented.

The main idea being tested is inter-VLAN routing using a single router interface with multiple sub-interfaces. In this design, the link between the switch and the router is a trunk, carrying multiple VLANs. On the router, each sub-interface represents a different VLAN and uses 802.1Q encapsulation, with its own IP address that serves as the default gateway for hosts in that VLAN. The router then routes traffic between those VLANs through these sub-interfaces, all over one physical connection. This arrangement is known as router on a stick.

This differs from a Layer 3 Switch approach, where inter-VLAN routing happens on the switch itself using SVIs and internal routing. The other terms—Sticky MAC and BPDU Guard—pertain to security and spanning-tree protections, not to how inter-VLAN routing is implemented.