Evaluation of the Catallaxy paradigm for decentralized operation of dynamic application networks

Future Grid network technology will face the problem of the efficient provisioning of services to clients by a scalable and dynamic resource allocation (matching) mechanism. The objective of CATNETS determined the applicability of a decentralized economic self-organization mechanism for resource allocation in application layer networks (ALN). The term ALN integrates different Internet overlay network approaches, like Grid and P2P systems. The Catallactic approach achieved positive evaluation in different scenarios. If the number of messages is low, the implemented approach outperforms centralized economic resource brokers. Varying distribution of services doesn¿t influence the outcome of the system significantly. Even in large scenario settings with hundreds of resource providers and services, the decentralized economic allocation approach still shows very good results. A detailed evaluation of the decentralized allocation approach is published on the CATNETS website. The source code of the implemented algorithms and its evaluation platforms are available for download, too.

The Grid is a promising technology for providing access to distributed computational capabilities such as processors or storage space. One of the key problems in current Grid infrastructures is deciding which jobs are to be allocated to which resources at what time. In this context, the use of market mechanisms for allocating resources is a promising approach toward solving these problems. The objective of CATNETS was to design, implement, and evaluate an auction mechanism for allocating and scheduling computer resources and services which have multiple quality attributes. The mechanisms are evaluated and compared to a decentralized approach according to their economic performance by means of a numerical simulation. A detailed evaluation of the allocation approach is published on the CATNETS website. The source code of the implemented algorithms and its evaluation platforms are available for download, too.

The applications developed demonstrate how the Catallactic middleware may be used to support service discovery in Application Layer Networks. The result demonstrates the benefit of using a de-centralized market-based mechanism over other approaches utilizing centralized registry services, as often found in existing applications based on a service-oriented architecture. The two applications were: - a distributed database query application over a product catalogue in the context of Civil/Architectural engineering; - a data analysis/mining workflow (composed of a data conversion, data analysis and data visualisation services). Both of the above applications involve the use of a batch-mode execution of services. To demonstrate generality, two case studies were developed. The first involved understanding how the Catallaxy approach could be used to support distributed rendering/visualisation within the UK National Grid Service, through close collaboration with partners in the UK Visualisation Network (UK VizNet -- http://www.viznet.ac.uk/). The report has formed the basis for further discussions with VizNet partners. The second involved understanding how the workflow approach could be used in the context of a Web 2.0-based mashup ¿ using the Google Maps API and reverse Geo-coding service (from Geonames.org). The applications and their setup scripts are available for download via the CATNETS Web site.

The result is twofold: architecture for the Catallactic middleware and the implemented middleware. The architecture provides the guidelines on how to build a Catallactic middleware. It shows the components needed and how they interact with each other. The architecture provides the basis for the design of the Catallactic middleware implementation. The implemented middleware is an instance of one of the possible ways of implementation. It allows exploring practical issues for further development. The implementation is in the stage of a prototype. Shifting it to production-quality would require significant additional tests and enhancements of components.

The CATNET simulation environment offers several tools for simulation economic resource allocation approaches in future P2P enabled application layer networks. This includes future Grid computing networks and service-oriented architectures. The tool set is composed of a manual and automated scenario generator, the core simulator, and a set of evaluation scripts. The automated scenario generator enables the creation of large network structures and the placement of available service and resources using build-in distributions. The scalable CATNETS simulator offers a P2P messaging infrastructure and allows the simulation of economic resource allocation mechanisms on top of it. For the implementation of software agent, the simulator provides easy-to-use interfaces and the advanced Grid time model speeds up simulation times. Both, proactive and reactive software agents are supported. A rich set of examples help to learn the simulator. The CATNETS metric pyramid provides a collection of metrics for evaluation of technical and economical resource allocation approaches. For the implemented centralized and decentralized allocation approach, a MATLAB script set for automated evaluation of simulation runs is available for metrics evaluation

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