Fault tolerance is a system's ability to continue operating properly in the event of a failure. This means that if one part of the system, like a server or a component, fails, the rest of the system can still function without interruption. For example, in a computer network, if one router goes down, other routers can take over its tasks, ensuring that data continues to flow smoothly. In many critical applications, such as banking or healthcare, fault tolerance is essential. It helps prevent data loss and maintains service availability, which is crucial for user trust and safety. By designing systems with redundancy, like having backup servers or alternative pathways, organizations can minimize the impact of failures and enhance overall reliability.