Authors: Stefan Pleisch, André Schiper

Title: Approaches to Fault-Tolerant and Transactional Mobile Agent Execution -- An Algorithmic View

Date: 2004-08-23 09:33:55

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 fault-tolerant 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.

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