  We consider the problem of failure detection in dynamic networks such as
MANETs. Unreliable failure detectors are classical mechanisms which provide
information about process failures. However, most of current implementations
consider that the network is fully connected and that the initial number of
nodes of the system is known. This assumption is not applicable to dynamic
environments. Furthermore, such implementations are usually timer-based while
in dynamic networks there is no upper bound for communication delays since
nodes can move. This paper presents an asynchronous implementation of a failure
detector for unknown and mobile networks. Our approach does not rely on timers
and neither the composition nor the number of nodes in the system are known. We
prove that our algorithm can implement failure detectors of class <>S when
behavioral properties and connectivity conditions are satisfied by the
underlying system.
