Which LAN topology below is MOST vulnerable to a single point of failure?

A.
FDDI

B.
Physical Star

C.
Logical Ring

D.
Ethernet Bus

Explanation:
Ethernet bus topology was the first commercially viable network topology, and consists of all
workstations connected to a single coaxial cable. Since the cable must be properly terminated on
both ends, a break in the cable stops all communications on the bus. * the physical star topology
acts like a logical bus, but provides better fault tolerance, as a cable break only disconnects the
workstation or hub directly affected. * logical ring topology, is used by Token Ring and FDDI and is
highly resilient. Token Ring employs a beacon frame, which, in case of a cable break, initiates auto
reconfiguration and attempts to reroute the network around the failed mode. Also, the Token Ring
active monitor station performs ring maintenance functions, like removing continuously circulating
frames from the ring. FDDI employs a second ring to provide redundancy. Sources: Virtual LANs by
Mariana Smith (McGraw-Hill, 1998) and Internetworking Technologies Handbook, Second Edition
(Cisco Press, 1998).