Towards JMS Compliant Group Communication - A Semantic Mapping

Lecture Notes in Computer Science, 2001

The Java Message Service (JMS) is a specification that provides a consistent Java API for accessing message-oriented middleware services. This paper presents a test harness that automates the testing of JMS implementations (providers) for correctness and performance. Since the JMS specification is expressed in informal language, a formal model for JMS behaviour is developed, based on the I/O automata used in other group communication systems. The test harness has been successfully used to test a number of JMS implementations. This paper contains a descriptive presentation of the formal model, the full details are found in a technical report.

1994

This paper presents a general architectural model for group communications which are communications that may involve more than two parties. The concept of group is presented and the concept of group association, which is an instance of group communication, is analysed. Those group associations are modelled as a set of basic components called multicast conversations. At the service boundery, new architectural concepts are introduced to identify a group association as well as its multicast conversations. Then, facilities to handle the group associations and the multicast conversations are defined and the properties of data transfer on a group association are examined. Finally, the paper deals with aspects of group management.

2009

This paper presents an analysis of the performance impact of two generic group communication APIs, namely Hedera and jGCS. The analysis was carried out in a four-node cluster by comparing the performance of different configurations of two well-known group communication middleware systems (i.e., JGroups and Spread), under different message sizes, both in standalone mode and when used as plug-ins for the two generic APIs. The results show that there are significant variations in the performance overhead imposed by each generic API on both JGroups and Spread, and that those differences are strongly related to variations in message size and the way each generic API is implemented. The paper also discusses whether it would be worth migrating from a standalone group communication implementation to a generic API.

1998

Group communication is a useful abstraction in the development of highly available distributed and communication-oriented applications in wide area networks (WANs). The most important aspects of this abstraction are the dynamic maintenance of group membership and its diverse semantics for interleaving membership change noti cations within the ow of regular messages.

International Journal of High Performance Systems Architecture, 2009

This paper presents an evaluation of the performance impact of two generic group communication APIs, namely Hedera and jGCS, over three well-known group communication systems, namely JGroups, Spread and Appia. The evaluation compared the performance of different configurations of the three group communication systems in a local clustered environment, under different message and cluster sizes, both in standalone mode and when used as plug-ins for the two generic APIs. The results show that there are significant differences in the overhead imposed by each generic API with respect to the performance of the three group communication systems, when used in standalone mode, and that those differences are strongly related to variations in message and also to the way the generic APIs and their plug-in mechanisms are implemented. Based on those results, the paper discusses some of the circumstances upon which it would be worth implementing group communication using the investigated systems.

Computer networks and ISDN systems, 1997

The World Wide Web has evolved from a distributed hypertext system to a platform-independent graphical user interface that integrates many network services. So far, its technology has restricted it mainly to applications for information retrieval. As networks become ubiquitious and more and more users have a permanent connection, there is an increasing demand for other network services, such as real-time data feeds, group communication, and teleconferencing. So far, these services have been provided by various proprietary software systems, which were hard to set up and use, and thus not very successful. Integrating real-time group communication services into the World Wide Web is a natural way to make them more accessible and will take the Web a step further on its way to becoming the universal network application. In this paper, we describe functionalities required for these services and present an implementation based on Sun Microsystem's Java programming language. We focus on the high-level functionalities and abstractions, but also describe an object-oriented programming model for group communication systems. Topics: Integration of real-time channels, innovative applications, programmatic and specialized user interfaces

1998

View-oriented group communication services are widely used for fault-tolerant distributed computing.

1995

Group Communication Paradigms play an important role in the management of group activities, such as reliable information diffusion in support of replication and cooperation. They consequently provide an appropriate framework for groupware applications support. To meet the new challenges posed by large scale distributed settings like the Internet, a new generation of group communication systems has emerged, built on the lessons learnt from early prototypes. This paper presents new services/features proposed by this new generation of systems and shows their relevance in the context of groupware support. Experiments with a cooperative application demonstrate how the features of a group-based system like NAVTECH can be used to enhance the functionality of groupware applications. NAVTECH is a modern group communication and activity support system developed at INESC. and the groupware applications requirements. Selecting key functionality of the groupware platform, we have shown that groups can be identified at different levels of the architecture and established a mapping to group support services .

Proceedings of the 2002 joint ACM-ISCOPE conference on Java Grande - JGI '02, 2002

Group communication is a crucial feature for high-performance and Grid computing. While previous works and libraries proposed such a characteristic (e.g. MPI, or object-oriented frameworks), the use of groups imposed specific constraints on programmers -for instance the use of dedicated interfaces to trigger group communications.

Although group context is an important element of user con- text, there are few services utilizing group context. A platform which provides group context will be essential when developing group-based services. GRECOM (Group Context Management Middleware for Group Event-based Services) works on each user's mobile device and recognizes high-level group context by exchanging the packets. Based on the col- lected group context, GRECOM resolves various requests of services. GRECOM also prevents leakage of privacy information using the access control policy, which is altered according to user's situation.