Which of the following statements about hubs is not true?

A. Hubs amplify and repeat signals received through one port out all other ports regardless of the destination.

B. Hubs provide internal crossover circuits and use uplink ports to form a hierarchical star.

C. Hubs are physical layer devices that connect network devices in a star topology.

D. Hubs are data link layer devices that connect network devices in a star or ring topology.

Answer :

The statement that is not true about hubs is D. Hubs are data link layer devices that connect network devices in a star or ring topology.

At the physical layer of the OSI model, hubs allow signals to be transmitted between devices that are connected to one another within a network. They don't take part in error control or logical addressing.

Hubs exclusively support a star network topology, where each device connects directly to the hub. Therefore, while hubs amplify and repeat signals in a star configuration, they do not operate at the data link layer or support ring topologies.