Checkpointing and Roll back Recovery Protocols in Wireless Ad hoc Networks: A Review.

The main focus in a single process checkpointing protocol is on finding optimal checkpoint interval to minimize the loss due to any fault, but in a distributed environment the main focus is on finding out and saving a global consistent state of the system. The challenge in finding a global consistent state is that interprocess communication creates dependencies that must be factored, otherwise the global checkpoint becomes useless. Mobile ad hoc networks throw up a plethora of challenges in tracking interprocess dependences including how to reliably save checkpoints in face of transience and node failures, where to save the checkpoints and how to reconstruct the stable global state from the nodes which are available after the fault. To add high availability and reliability to mobile networks, checkpoint based rollback recovery techniques are widely applicable. Checkpointing methods for traditional distributed systems cannot be applied directly to the mobile networks. This paper provides an overview of the available checkpointing strategies for mobile networks, comparing them on the various parameters. We conclude that no single strategy is optimal in all fault scenarios and that the perfect strategy may still be in the works. [ABSTRACT FROM AUTHOR]