CompTIA Network+ N10-006 Q20

Which of the following network topologies has a central, single point of failure?

A. Ring
B. Star
C. Hybrid
D. Mesh

Correct Answer: B
Section: Network architecture

Explanation:
A Star network is the most common network in use today. Ethernet networks with computers connected to a switch (or a less commonly a hub) form a star network.
The switch forms the central component of the star. All network devices connect to the switch. A network switch has a MAC address table which it populates with the MAC address of every device connected to the switch. When the switch receives data on one of its ports from a computer, it looks in the MAC address table to discover which port the destination computer is connected to. The switch then unicasts the data out through the port that the destination computer is connected to.
The switch that forms the central component of a star network is a single point of failure. If the switch fails, no computers will be able to communicate with each other.