Comparative Study of QoS Parameters for Different Web Services

Web service plays an important role in the new paradigm of distributed computing over the Internet. Web service allows to combine different publicly available services together to create new functionalities. Many public web services can be used at free of cost. Two important elements of web services are Web Services Description Language (WSDL) used for describing and locating web services and Simple Object Access Protocol (SOAP) used for communicating between applications via the Internet. The consumers of web services are always keen to differentiate between QoS-aware and QoS-unaware web services. Measuring QoS is the prerequisite for designing QoS-aware web services. Therefore, a number of metrics need to be identified. Because of the dynamic and unpredictable nature of the web services infrastructure, providing the acceptable QoS is really a challenging task. In this paper we have identified three dominating features–response time, reliability and security–that governs the QoS of a web service. The objective of this work is to carry out a comparative study between publicly available web services by measuring different metrics of QoS for these web services. Hence, using different open-source tools we propose a simplified approach to measure those QoS metrics for publicly available web services. Based on our approach, QoS-aware web services can easily be built from publicly available services.