Background: Know: failure Recognize:
When a communication channel fail, the channel completely stops transmitting messages. Intermittent failure When a communication channel can lose a certain number of messages but is still able to deliver some correctly.
Fail-fast is a property of a system or module with respect to its response to failures. A fail-fast system is designed to immediately report at its interface any failure or condition that is likely to lead to failure.
It is an arbitrary fault that can occur during the execution of a distributed system’s algorithm. When a Byzantine failure has occurred, the system may respond in any unpredictable way, unless it is designed to have Byzantine fault tolerance.
Most failures are fail-stop.
eg. routers advertising unavailable destinations; of particular concern in Mobile ad hoc networks