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).