End-to-End Application. Execution <xsd:sequence> <xsd:element name="application" type="xsd:string"/> <xsd:element name="timeSteps" type="xsd:int"/> <xsd:element name="executionMode" type="xsd:string"/> <xsd:element name="outputDestination" type="xsd:string"/> </xsd:sequence> Providing an end-to-end application service based on remote execution requires coordinating several subsidiary services. In our case the workflow scenario is very simple and consists of application execution and data transfer of output data. The serviceDescription exposes interface similar to application execution: As before, the service description externalizes arguments on which the QoS depends; in this case we add the argument describing the destination of the data to those on job execution. In this way, the end-to-end timebound calculation can be adjusted to the location in which the execution is eventually scheduled. The end-to-end application service directly depends on the job execution and data transfer services for its service level. We currently store those dependencies as the dependency element of AgreementTermType. Negotiating a composite agreement is more complex as it requires the factory to in turn to negotiate subsidiary agreements. Further, dependencies between multiple components may impose an order on negotiating subsidiary agreements. The end-to-end time is calculated by combining execution times of the services in appropriate ways (in our case by adding, but in general we could use min/max, etc.) and using the confidence level of subsidiary services to calculate a weighted error. As with the other services, the workflow and its subsidiary services are instantiated when the availability period starts. Claiming an agreement on an application service will trigger claims on subsidiary services. In principle, by externalicing the application description as a workflow rather than an opaque service we could both express a stronger dependency and subject much of what is currently embedded implementation to automatic management. While full implementation of this concept would require incorporating a workflow language into our agreement structure, we made some modest steps in that direction by for example externalizing service monitoring.
