No abstract

No abstract

Recent developments in telecommunications have allowed drawing new paradigms, including the Internet of Everything, to provide services by the interconnection of different physical devices enabling the exchange of data to enrich and automate people's daily activities; and Fog computing, which is an extension of the well-known Cloud computing, bringing tasks to the edge of the network exploiting characteristics such as lower latency, mobility support, and location awareness. Combining these paradigms opens a new set of possibilities for innovative services and applications; however, it also brings a new complex scenario that must be efficiently managed to properly fulfill the needs of the users. In this scenario, the Fog Orchestrator component is the key to coordinate the services in the middle of Cloud computing and Internet of Everything. In this paper, key challenges in the development of the Fog Orchestrator to support the Internet of Everything are identified, including how they affect the tasks that a Fog service Orchestrator should perform. Furthermore, different service Orchestrator architectures for the Fog are explored and analyzed in order to identify how the previously listed challenges are being tackled. Finally, a discussion about the open challenges, technological directions, and future of the research on this subject is presented.

No abstract

Web-services are supported by a complex software infrastructure that must provide a robust service to the client applications. This practical experience report presents a practical approach for the evaluation of the robustness of web-services infrastructures. A set of robustness tests (i.e., invalid web-services call parameters) is applied during web-services execution in order to reveal possible robustness problems in the webservices code and in the application server infrastructure. The approach is illustrated using two different implementations of the web-services specified by the TPC-App performance benchmark running on top of the JBoss application server. The proposed approach is generic and can be used to evaluate the robustness of web-services implementations (relevant for programmers) and application server infrastructures (relevant for administrators and system integrators).