Real-time control and management of distributed applications using ip-multicast

Abstract A central issue within any distributed computer environment is how to control and manage running applications. This paper presents an implementation of a framework for control and management of distributed applications and components using IPmulticast. The framework allows for easy and scalable control of single applications, groups of applications or parts of applications using a new agent based architecture. Messaging is done using the Control Bus and the Scalable Reliable Real-time Transfer Protocol for reliable distribution of data. The paper presents how this framework is integrated into Java based applications and how developers specify access points. The paper also presents an application called multicast Manager -mManager, a Java implementation that provides a user interface to the framework. The mManager allows administrators to get an overview of currently running applications and if necessary control these applications. The paper presents example usage scenarios where the framework is used to create bandwidth adaptive applications and better group awareness

Robust Audio Transport using mAudio

IP-based groupware applications, such as net-based learning environments, rely on robust audio transport for efficient communication between users. This paper therefore gives an overview and an initial evaluation of how to achieve robust transport of real-time audio streams over Internet connections without service guarantees. Due to faulty hardware and network congestion, these connections face loss, packet delay and delay variation. Audio streams are especially sensitive due to their real-time characteristics, and the end result of non-robust transport is degradation of the perceived quality. Packet loss can be repaired using receiver-only, sender-initiated or receiver-initiated techniques. Depending on the actual network condition, an optimal technique can be selected using adaptive behavior together with loss-recovery techniques in the applications. Studies have shown that loss rates of up to 20 % can be effectively repaired using fairly simple techniques. The paper gives initial results from subjectively evaluating audio quality and presents a research prototype called mAudio that has been used to experiment with different loss recovery techniques

Real-Time Control and Management of Distributed Applications using IP-Multicast

A central issue within any distributed computer environment is how to control and manage running applications. This paper presents an implementation of a framework for control and management of distributed applications and components using IPmulticast. The framework allows for easy and scalable control of single applications, groups of applications or parts of applications using a new agent based architecture. Messaging is done using the Control Bus and the Scalable Reliable Real-time Transfer Protocol for reliable distribution of data. The paper presents how this framework is integrated into Java based applications and how developers specify access points. The paper also presents an application called multicast Manager - mManager, a Java implementation that provides a user interface to the framework. The mManager allows administrators to get an overview of currently running applications and if necessary control these applications. The paper presents example usage scenarios where the f..

A Framework for Management and Control of Distributed Applications using Agents and IP-multicast

As more and more applications on the Internet become network aware the need and possibility to remotely control them becomes larger. This paper presents a framework for control and management of distributed applications and components. This is done using IP-multicast and an agent based application architecture. The target of the framework is to allow for resource discovery of both controllable elements and available control points in the these elements as well as real-time control. All this is done in scalable and secure way based on IP-multicast and asymmetric cryptography. The presented framework is also independent of the underlying transport mechanism to allow for flexibility and easy deployment. The framework bandwidth usage and introduced control delay is presented. Details on the reference implementation of the framework and example usage scenarios where the framework is used to create bandwidth adaptive applications and better group awareness is also presented

Net-based Learning for the Next Millennium

Luleå University of Technology has for the last few years been deploying a net-based learning environment, mStar, to distribute courses to students independent of time and geographic distance. The mStar environment gives remotely and traditionally attending students equal possibilities to take an active part of a course, in addition to enhancing the learning experience for all students. This is made possible through a novel combination of IP-multicast technology and the WWW. This paper reports on experiences gained over a few years of practice and depicts a vision of the next generation of the mStar environment

HOL-Z in the UniForM-Workbench - a Case Study in Tool Integration for Z

. The UniForM-Workbench is an open tool-integration environment providing type-safe communication, a toolkit for graphical user-interfaces, version management and configuration management. We demonstrate how to integrate several tools for the Z specification language into the Workbench, obtaining an instantiation of the Workbench suited as a software development environment for Z. In the core of the setting, we use the encoding HOL-Z of Z into Isabelle as semantic foundation and for formal reasoning with Z specifications. In addition to this, external tools like editors and small utilities are integrated, showing the integration of both self-developed and externally developed tools. The resulting prototype demonstrates the viability of our approach to combine public domain tools into a generic software development environment using a strongly typed functional language. 1 Introduction The need for tool integration has been widely recognised throughout software engineering. There is ..