The Data Exchange Logging Service (DELS) provides evidence that data has been (a) submitted and (b) received and (c) rules and obligations (Data Usage Policies) were enforced or violated. This supports the clearing of operational issues, but also eventually the clearing of fraudulent transactions.
The data provider can track that, how, and what data was provided and the consumer can be notified about this. The data consumer can track that this data was received or not received. Additionally, the data consumer can track and provide evidence on the enforcement of data usage policies or violation of data usage policies (Although the evidence is weak, as long as there are no sufficient measures for data usage policy enforcement in place). The log can be used as a basis for clearing and billing, but this is not in scope for Release 1. Business transactions for the DELS and the DCS should be defined by the federator operating those services.
From a functional perspective, the DELS provides an interface to track logging notifications and to read the logging messages afterward. The logging mechanism is specified in accordance to W3C linked data notifications.
The notification therefore includes minimal requirements, e.g. date, time, (a reference to) sender, data provider, data consumer, data exchange contract. The parties involved in the data exchange are typically sender and consumer of notifications. Some use cases may also require the consumption of the notifications by a 3rd eligible party.
The provisioning of notifications into the DELS can be enforced by mechanisms implemented in the data consumers and data providers systems or by cryptographic mechanisms (forced logging).