In a nutshell, openWNS now decouples the generation and publication of measurements from their processing, may that be logging, filtering, sorting or simply storing them. In the following, it will shortly be explained what generation, publication and processing are about.
Generating measurement values is up to you, the Implementer of a certain, class, module, node, whatever that might be. Measurements may currently be everything that can be represented by a double value, like SINR, Interference, Power values, delay times, packet sizes, throughput figures ...
Assuming you have obtained a measurement, you would like to publish it so it can be handled in any way you desire. When publishing the measurement, it is not necessary to know in which way and by whom it is being processed. However, the entities that do process the measurement may require certain additional information about the circumstances under which the measurement was taken, e.g. which Node has taken the measurement, at which point in the scenario it was taken, what kind of node took it, which Traffic Category the measured packet belongs to, where the packet originated from, etc. etc.
We refer to this kind of information as the so called context of the measurement. Hence, the process of publishing the measurement involves gathering and compiling this Context and then forwarding everything to the appropriate processing entities. All this is handled by the so-called ContextCollector. The only information the ContextCollector needs to have about the processing of the measurements is a configurable name of the processing channel into which to forward the measurement and the context info.
Entry points to the existing processing channels are governed by a global registry called the wns::probe::bus::ProbeBusRegistry. They may be accessed via the aforementioned name. NOTE that the processing channels (further referred to as the ProbeBusses) are centralized, while the publication of measurements is distributed. This means that all entities that take and publish measurements of the same type have a ContextCollector of their own, but all these ContextCollectors forward their measurements and context into the same wns::probe::bus::ProbeBus.
Processing of measurements is accomplished by the so called
wns::probe::bus::ProbeBus. The ProbeBus is an object that supports hierarchical chaining to form trees of ProbeBusses. The measurement and the
wns::probe::bus::context are inserted at the root of the tree and each node may store and forward the received measurement, depending on the outcome of an internal decision unit that determines whether or not the current node will accept the measurement. By appropriate combination and parameterization, the said tree can then be used to filter and thus sort the measurements based on the available context information. openWNS provides a toolbox of different ProbeBus implementations that can be flexibly combined to accomplish all kinds of measurement processing tasks. In addition, the simple
wns::probe::bus::ProbeBus interface and the very generic wns::probe::bus::context::IContext information concept allow for the quick prototyping of tailor-made solutions.
1.5.5