When routing a large number of VLANs, what are two disadvantages of using the router-on-a-stick inter-VLAN routing method rather than the multilayer switch inter-VLAN routing method? (Choose two.)

Question:
When routing a large number of VLANs, what are two disadvantages of using the router-on-a-stick inter-VLAN routing method rather than the multilayer switch inter-VLAN routing method? (Choose two.)

• Multiple SVIs are needed.
• A dedicated router is required.
• Router-on-a-stick requires subinterfaces to be configured on the same subnets.
• Router-on-a-stick requires multiple physical interfaces on a router.
• Multiple subinterfaces may impact the traffic flow speed.

Explanation: With the router-on-a-stick inter-VLAN routing method, a dedicated router is required. It only needs one physical interface on the router to route traffic among multiple VLANs, by using subinterfaces on one physical interface. On the other hand, since traffic of all VLANs will have to go through the same physical interfaces, the throughput will be impacted. Also, a multilayer switch can use multiple SVIs to perform inter-VLAN routing.

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