Centralized versus Decentralized Conversation-based Orchestrations

Abstract

There has been a great deal of interest in recent years in the use of service oriented approach and relevant standards to implement business processes. Following the concepts of workflow-based process management, the major focus has been on service composition. Not surprisingly, this default composition approach suffers from the limitations of centralized workflow management. It is well recognized that a decentralized execution setting where composed services can establish P2P interactions, is central to the management of a wide range of ubiquitous, mobile, large-scale and secure business processes. A natural way to enable the decentralized execution is to implement the relevant distributed cooperating processes of a centralized process on composed services. In this way, composed services can establish P2P interactions following the semantics of their processes. In this paper, we present a generic approach that enables decentralized executions with such cooperating processes. Precisely, we present our method that derives the latter. We focus on the sophisticated control/data flow and conversational aspects that run counter to naive intuition, most of which, we explain using deeper analysis of the algorithms and data structures that we employed.

Design and Implementation of Information Flow-sensitive Business Processes

“…In addition to basic control and data dependencies, the interactions that implement the elimination of dead paths must be considered as in [24] [9]. Figure 2 illustrates four essential cases that must be considered in implementing the decentralization operation that produces cooperating fragments.…”

“…Furthermore, their design and implementation assumptions are contradictory to the new requirements of service oriented architectures. In [24], we presented our approach to the decentralized service composition. It consists of deriving decentralized and cooperating process fragments from a centralized workflow-like composition specification.…”

Designing Decentralized Service Compositions: Challenges and Solutions

“…This operation is detailed in the next subsection. We explain the algorithm with examples taken from our previous papers [19] [20].…”

“…The activities that collect "true" messages are followed by activities that read the sent data (line 14). The last step of •a i is the collection of data that are sent by processes that execute the elements of •a i,ss (line [20][21][22]. It should be noted that the latter do not require the execution of activities that test the status of source activities.…”

A Flexible Approach for Automatic Process Decentralization Using Dependency Tables

“…Similar process partitioning approaches have been applied to different needs such as the implementation of secure interactions [3] or the decentralized exception handling [7]. In [27] [26], the decentralization of processes has been studied in an abstract manner by extending the dead path elimination operation of workflow management systems. The decentralization focuses on the preservation of the centralized specification by preventing possible blocking situations.…”