Question

A high school uses VLAN15 for the laboratory network and VLAN30 for the faculty network. What is required to enable communication between these two VLANs while using the router-on-a-stick approach?

A. Two groups of switches are needed, each with ports that are configured for one VLAN.
B. A switch with a port that is configured as a trunk is needed when connecting to the router.
C. A router with at least two LAN interfaces is needed.
D. A multilayer switch is needed.

Answer 1

To enable communication between VLAN15 and VLAN30 using a router-on-a-stick approach, a switch port needs to be configured as a trunk. The router will have a single interface configured with sub-interfaces for each VLAN to route traffic between them. The correct option is B. A switch with a port that is configured as a trunk is needed when connecting to the router.

Step-by-step explanation:

To enable communication between VLAN15 for the laboratory network and VLAN30 for the faculty network using the router-on-a-stick approach, B. A switch with a port that is configured as a trunk is needed when connecting to the router.

This means that a single physical router interface is used to interconnect multiple VLANs present on a switch. This interface on the router is configured to be able to understand and process tags created by the IEEE 802.1Q protocol, which is used for transporting traffic for multiple VLANs over a single interface (trunk link).

To accomplish this, the router's single interface is sub-interface configured with each VLAN. On the switch side, at least one switch port must be configured to act as a trunk port to allow tagged frames for multiple VLANs to travel between the switch and the router.

Essentially, this trunk port will carry traffic from both VLAN15 and VLAN30 to the router, which will then route between these VLANs as needed.

The correct option is B. A switch with a port that is configured as a trunk is needed when connecting to the router.