Beytullah Yildiz

On the costs for reliable messaging in Web/grid service environments

As Web services have matured they have been substantially leveraged within the academic, research and business communities. An exemplar of this is the realignment, last year, of the dominant grid application framework - Open Grid Services Infrastucture (OGSI) - with the emerging consensus within the Web services community. Reliable messaging is an important component within the Web services stack. There are two competing, and very similar, specifications within this domain viz. WS-ReliableMessaging (WSRM) and WS-reliability (WSR); this work focuses on the WSRM specification. In this paper we provide an overview of the WSRM protocol, describe our implementation of WSRM, and present an analysis of the costs (in terms of latencies and memory utilizations) involved in the use of WSRM. Since WSRM is very similar to WS-reliability we expect the performance of WSRM to be very similar to that of WSR. We hope that the work presented here helps researchers and systems designers gauge the suitability of Web services based reliable messaging in their applications and also to make appropriate trade-offs, which includes inter alia interoperability, guarantees, quality of service and performance

An Orchestration for Distributed Web Service Handlers

Web service is a standardization effort to interoperate loosely-coupled applications. A Web service interaction benefits and sometimes requires additive functionalities, called as handlers. They contribute to build rich, modular and efficient Web services. However, the way of utilizing them is very crucial for the Web service architecture and its overall performance. Using distributed approach for the handler execution facilitates significantly to obtain full benefit from them. In this paper we describe an orchestration structure for the handlers to attain richer, more modular and efficient Web services.

Performance of a possible Grid message infrastructure

In this paper we present the results pertaining to the NaradaBrokering middleware infrastructure. NaradaBrokering is designed to run on a large network of cooperating broker nodes. NaradaBrokering capabilities include, among other things, support for a wide variety of transport protocols, Java Message Service compliance, support for routing JXTA interactions, support for audio/video conferencing applications and, finally, support for multiple constraint specification formats such as XPath, SQL and regular expression queries. This paper demonstrates the suitability of NaradaBrokering to a wide variety of applications and scenarios. Copyright

Toward a modular and efficient distribution for Web service handlers

Over the last few decades, distributed systems have architecturally evolved. One recent evolutionary step is SOA. The SOA model is perfectly engendered in Web services, which provide software platforms for building applications as services. Web services utilize supportive capabilities such as security, reliability, and monitoring. These capabilities are typically provisioned as handlers, which incrementally add new features. Even though handlers are very important, the method of utilization is crucial for obtaining potential benefits. Every attempt to support a service with an additional handler increases the chance of an overwhelmingly crowded handler chain. Moreover, a handler may become a bottleneck because of its comparably higher processing time. In this paper, we present the Distributed Handler Architecture to provide an efficient, scalable, and modular architecture. The performance and scalability benchmarks show that the distributed and parallel handler executions are very promising for suitable handler configurations. The paper is concluded with remarks on the fundamentals of a promising computing environment for Web service handlers. Copyright

Experiences in Deploying Services within the Axis Container

The Web Services framework, since it leverages the Service Oriented Architecture model, enables the development of applications that are loosely coupled and easier to manage. A Web Service is typically hosted within a Web Service Container. There are several choices for these containers depending on the platform and the language in which the applications would be developed. In this paper our focus is on applications built using the Java platform. Here, the most dominant Web Service container is the opensource Apache Axis Web Service container. In this paper we describe our experiences in deploying Web Services, specifically WS-ReliableMessaging, within this container. We enumerate the problems and limitations that we encountered within Axis, and our solutions to get around this problem. We also have a set of recommendations that would make this a more flexible container for sophisticated Web Service applications.

Measuring overhead for distributed web service handler

Service Oriented Architecture perfectly manifests itself in Web services, which create seamless and loosely-coupled interactions. Web service utilizes supportive functionalities such as security, reliability and so on. These functionalities are called as handlers, which incrementally add new capabilities. However, adding new handlers into the execution path may cause performance and scalability problems. Distribution of handlers solves these problems by providing abundant computing resources. However, pulling a handler out of its native place and positioning it away from Web service endpoint brings additional costs. Hence, we will investigate the overhead of handler distribution for various environments.