Why optimistic message logging has not been used in telecommunications systems

Much of the literature on message logging and checkpointing in the past decade has been based on a so-called optimistic approach that places more emphasis on failure-free overhead than recovery efficiency. Our experience has shown that most telecommunications systems use a pessimistic approach because the main purpose of using message logging and checkpointing is to achieve fast and localized recovery, and the failure-free overhead of a pessimistic approach can often be made reasonably low by exploiting application-specific information.<>