Abstract This report presents a distributed service that allows nodes in an overlay network to agree locally on the extent of crashed regions in their neighbourhood. Our service is local is that it only involves nodes in the vicinity of a crashed region. It is convergent as nodes that propose overlapping and hence conflicting regions are forced to reconcile their views before deciding. In this report, we motivate the need for such a service, formally specify its properties, propose an implementation, and prove its correctness. |