Fault-tolerant mobile agent execution

Abstract

Abstract-Mobile agents have attracted considerable interest in recent years. In the context of mobile agents, fault tolerance is crucial to enable the integration of mobile agent technology into today's business applications. This article identifies two important properties for fault-tolerant mobile agent execution: nonblocking and exactly-once. Nonblocking ensures that the agent execution can proceed despite a single failure of the agent or the machine, for instance. Replication is the generally adopted mechanism to prevent blocking, but may lead to multiple executions of the agent (i.e., a violation of the exactly-once property), which is undesirable with operations that have side effects. Hence, we propose that fault-tolerant mobile agent execution be modeled as a sequence of agreement problems. Our approach is nonblocking and ensures exactly-once execution. FATOMAS, our prototype fault-tolerant mobile agent system, implements our approach. Its performance evaluation illustrates the overhead of the replication mechanisms.

A Systematic Review of Fault Tolerance in Mobile Agents

“…Transactional Non-transactional Checkpoint [5], [38], [36], [27], [30], [26], [42] [34], [45], [48], [46], [32] Replication [29], [39], [7], [47], [35] [43], [40], [41], [33], [44], [25], [28] Hybrid [14], [31] -------Further analysis shows that both check-pointing and replication-based schemes are used almost equally over the years of consideration (see Figure 6). …”

“…Table 2 presents the existing implementations of each study and the failure types designed for them. [25], [30], [31], [32], [42], [36], [38], [39], [43], [44], [45] [5], [7], [25], [26], [27], [29], [30], [31], [32], [34], [42], [35], [36], [38], [40], [41], [14], [44], [46], [47], [43], [45] [25], [26], [5], [27], [28], 29], [30], [31], [32], [33], [42], [7], [36], [38], [39], [40], [41], [44], [46], …”

“…Commit and abort are both irreversible and unlike consensus, transaction can only be committed if all participating sites vote or agree to commit, otherwise, the transaction is aborted. In this study, analysis shows that most of the studies used the basic transaction-commit protocol such as centralized transaction commit by [26] while [7], [27], [30], [35], [36], [47] used the transaction commit protocol. A hybrid approach of both consensus and transaction-based protocol were implemented by [29], [47], [7], [38].…”

“…Achieving mobile agent's fault tolerance requires the adherence to the non-blocking and exactly-once execution [7]. Presently in literature, several mobile agents' fault tolerance approaches exist in variety of mobile agent platforms.…”

“…Protocols under this category include the pessimistic and optimistic logging protocol [7]. Pessimistic execution ensures that changes are applied only if no agent crashes and there is no erroneous result, while in optimistic execution the place modifications can be immediate and transparent but undoing modifications is a complex task [7].…”