CompTIA Security+ Question L-41

A router has a single Ethernet connection to a switch. In the router configuration, the Ethernet interface has three sub-interfaces, each configured with ACLs applied to them and 802.1q trunks.
Which of the following is MOST likely the reason for the sub-interfaces?

A. The network uses the subnet of
B. The switch has several VLANs configured on it.
C. The sub-interfaces are configured for VoIP traffic.
D. The sub-interfaces each implement quality of service.

Answer: B

A subinterface is a division of one physical interface into multiple logical interfaces. Routers commonly employ subinterfaces for a variety of purposes, most common of these are for routing traffic between VLANs. Also, IEEE 802.1Q is the networking standard that supports virtual LANs (VLANs) on an Ethernet network.