The LAN needs are expanding at the Testking corporate office, which is quickly growing. You are instructed to enlarge the area covered by a single LAN segment on the TestKing network. Which of the following are layer 1 devices that you can use? (Choose all that apply.)

A. A switch
B. A router
C. A network adapter card
D. A hub
E. A repeater

Answer: D, E

Explanation:

A hub simply repeats the electrical signal and makes no attempt to interpret the electrical
signal (layer 1) as a LAN frame (Layer 2). So, a hub actually performs OSI layer 1
functions, repeating an electrical signal, whereas a switch performs OSI layer 2 functions,
actually interpreting Ethernet header information, particularly addresses, to make
forwarding decisions. Hubs can be used to increase the number of stations that can be
supported on a LAN.

Because the repeater does not interpret what the bits mean, but does examine and
generate electrical signals, a repeater is considered to operate at Layer 1. Repeaters can be
used to physically extend the LAN to greater distances.