The DECOS integrated architecture tries to combine the benefits of federated and integrated architectures by decomposing a large real-time system into nearly-independent distributed application subsystems (DASs) and integrating them on a single distributed computer system.
The communication infrastructure for the DASs is provided by virtual networks that are implemented on top of a time-triggered core architecture. Often it is necessary for a DAS to exchange information with another DAS, which is the task of a gateway. Gateways in the DECOS architecture are implemented as hidden gateways (i.e. transparent to the application). Gateways not only have to forward messages from one network to another, they are also used to resolve operational or semantic property mismatches between the interconnected networks. Another important task of gateways is the provision of an encapsulation service that is responsible for error containment and the selective redirection of messages in order to save bandwidth.
The goal of this thesis is the validation of the gateway services by experimental evaluation. To solve this task in a convenient way, we proposed the use of a measurement framework that has the ability to monitor the system under test and is capable of automated execution of testruns.
First we show a model of a framework that is generally applicable. The model consists of a test controller and monitor and an execution environment in which the tests are executed. The test controller feeds the execution environment with parameters that are extracted from test descriptions and controls and monitors the target hard- and software at runtime. We pursue the approach of software implemented fault injection at runtime.
Faults are injected by providing faulty parameters to the application.
Then we present an actual implementation for the evaluation of our exemplary DECOS cluster. Test descriptions are written in XML and are read by the control application that extracts the necessary parameters for the test runs and provides them to the target system. The application jobs on the target system are responsible for the execution of testruns and recording their operations which are then analyzed by the control application. The properties we are interested in are latencies and bandwidths via the gateways as well as the correct functionality of their error containment and selective redirection mechanisms.