With the ongoing internationalization of virtual laboratories, the integration aspect becomes more important. The meanwhile commonly accepted ’glue’ for such legacy systems are service oriented architectures, based on standardized and accepted Web service standards. We present our concept of the ’experiment as a service’, where the idea of service-based architectures is applied to virtual remote laboratories. In our laboratory middleware, experiments are represented as stateful service implementations and jobs as logical service instances of these implementations. We discuss performance, reliability, security and monitoring issues in this approach, and show how the resulting infrastructure - the Distributed Control Lab - is applied in the European VetTrend project.