Approaches to fault-tolerant and transactional mobile agent execution---an algorithmic view

Abstract

Over the past years, mobile agent technology has attracted considerable attention, and a significant body of literature has been published. To further develop mobile agent technology, reliability mechanisms such as fault tolerance and transaction support are required. This article aims at structuring the field of fault-tolerant and transactional mobile agent execution and thus at guiding the reader to understand the basic strengths and weaknesses of existing approaches. It starts with a discussion on providing fault tolerance in a system in which processes simply fail. For this purpose, we first identify two basic requirements for faulttolerant mobile agent execution: (1) non-blocking (i.e., a single failure does not prevent progress of the mobile agent execution) and (2) exactly-once (i.e., multiple executions of the agent are prevented). This leads us to introduce the notion of a local transaction as the basic building block for fault-tolerant mobile agent execution and to classify existing approaches according to when and by whom the local transactions are committed. In a second part, we show that transactional mobile agent execution additionally ensures execution atomicity and present a survey of existing approaches. In the last part of the survey, we extend the notion of fault tolerance to arbitrary Byzantine failures and security-related issues of the mobile agent execution.

Efficient Agreement Protocols in Asynchronous Distributed Systems

“…Regarding its communication capabilities, during the visit of an agent, a node can provide an IP address which can be used later to contact this node directly. The concept of transactional mobile agent [51] has been introduced as a mix between the agent technology and the transactional model. During its move, the agent discovers and visits n places that satisfy the n requests.…”

“…Thus the heterogeneity of the environment that characterized our targeted applications is not a major constraint and do not prevent the use of agents. Through the concept of transactional agent, It has been proved that transaction processing can also be implemented following the agent based approach: the concept of transactional agent has been studied in several works [51,49]. When a client launches a transaction T α , a mobile agent A α is created.…”

Network fault detection with Wiener filter-based agent

“…Conversely, with rising demands on processing power and the need to conserve bandwidth on large and slow networks, the restrictions of this approach have become conspicuous. The CS model is suitable for the applications with a limited need for distributed control (Pleisch and Schiper, 2004). Undoubtedly, this limits the flexibility with which a client can use a server, by processing the server data locally according to the client's needs.…”

“…MA is a software entity that basically exists in a software environment (Liotta, 2001;Pleisch and Schiper, 2004;Richard and Lipperts, 2002). Mobile agents (MA) is an agent that is able to move between different machines or, in a more abstract sense, between various individual network locations.…”

A timed mobile agent planning approach for distributed information retrieval in dynamic network environments

“…Several mobile agent systems provide a mechanism that makes mobile agents persistent, since persistency is helpful in critical situations, such as a connectivity loss or a power shortage; it provides fault-tolerance by duplicating and storing agent copies before starting critical operations. Although this mechanism achieves a trivial level of fault-tolerance, persistence on its own is insufficient [8,39]. There have been several suggestions for ways to implement fault-tolerance in mobile agents, e.g., the exception handling approach [35], Fatomas [38].…”