Checkpointing and Roll back Recovery Protocols in Wireless Ad hoc Networks: A Review
Jawahar Thakur, Arvind Kalia, Lalit Kumar Awasthi · INTERNATIONAL JOURNAL OF NEXT-GENERATION COMPUTING · 2015
Abstract: Haerder and Reuter’s definition of a checkpoint is quite general. They indicate that it is a “collection of information in a safe place, which has the effect of defining and limiting the amount of REDO recovery required after a crash,” Checkpointing and rollback recovery are widely used techniques for achieving fault tolerance in distributed systems. Chekpointing is the process of saving the state of a process on stable storage. Checkpoint is defined as a designated place in a program at which normal processing is interrupted specifically to preserve the status information necessary to allow resumption of processing at a later time. 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 major problem in finding out global consistent state is that the interprocess communication creates dependencies that must be considered for saving the consistent state, otherwise the global checkpoint become useless. The major challenges in a mobile ad hoc networks is how to track the interprocess dependences and where to save the checkpoints of mobile nodes which are available after the fault. Wireless computing systems often suffer from high failure rates that are transient and independent in nature. To add high availability and reliability to such distributed system checkpoint based rollback recovery techniques are widely applicable. Checkpointing methods for traditional distributed systems cannot be applied directly to the mobile networks. Researchers proposed a lot of new checkpointing methods for the mobile networks. This paper intends to present a review of the checkpointing strategies in the mobile networks based on the various parameters and observed that no single technique is suitable to fulfill all the criteria of optimality for such system. An effort has been made to bring out the possible features of existing protocols for ad hoc networks. Keywords: fault tolerance, rollback recovery, checkpointing, synchronous, asynchronous, quassi-synchronous, domino effect, mobile host, mobile support station. Orphans messages.