What is a key disadvantage of bus topology?

In a bus topology, all devices share a single communication line or bus to transmit data. This setup leads to a significant vulnerability known as a "single point of failure." If the main bus or cable fails, all devices connected to that bus lose communication with each other, effectively disrupting the entire network. This characteristic makes bus topology particularly risky for larger networks, as the failure of one section can incapacitate the entire system, leading to downtime and requiring repairs before normal operations can resume.

The other choices highlight attributes that are either advantages or less critical issues in the context of bus topology. Redundant connections, for instance, which are typically beneficial for reliability, are minimal in bus topologies, as they usually involve a single line. Efficient data transfer is not a disadvantage but more of an advantage in specific scenarios, although it may become compromised due to collisions when multiple devices attempt to send data simultaneously. Similarly, complex implementation is not a defining characteristic of bus topology, as it is generally simpler and more straightforward than other network topologies, such as mesh or star configurations.