QOS-based Checkpoint ProtOcOl for Multimedia Network Systems

Abstract

Advanced computer and network technologies have lead to the development of computer networks. Here, an application is realized by multiple processes located on multiple computers connected to a communication network such as the Internet. Each process computes and communicates with other processes by exchanging messages through communication channels. Mission- critical applications are required to be executed fauIt- tolerantly. That is, even if some processes fail, execution of an application is required to be continued. One of the important methods to realize fault-tolerant networks is checkpoint-recovery[2,4,6,7,10–12,16,19–21]. During failure-free execution, each process takes local checkpoints by storing state information into a stable storage [14]. If a certain process fails, the processes restart from the checkpoints by restoring the state information from the stable storage. For restarting execution of applications correctly in conventional data communication networks, a set of local checkpoints taken by all the processes and from which the processes restart should form a consistent global checkpoint [3]. A global checkpoint is defined to be consistent if there is neither orphan nor lost message. However, in a multimedia communication network, applications require transmission of large-size multimedia messages and low overhead failure-free execution rather than complete consistency. Hence, this paper proposes a novel criteria for consistent global checkpoints based on properties of multimedia communication networks and applications.