  The ATLAS Event Streaming Service (ESS) at the LHC is an approach to
preprocess and deliver data for Event Service (ES) that has implemented a
fine-grained approach for ATLAS event processing. The ESS allows one to
asynchronously deliver only the input events required by ES processing, with
the aim to decrease data traffic over WAN and improve overall data processing
throughput. A prototype of ESS was developed to deliver streaming events to
fine-grained ES jobs. Based on it, an intelligent Data Delivery Service (iDDS)
is under development to decouple the "cold format" and the processing format of
the data, which also opens the opportunity to include the production systems of
other HEP experiments. Here we will at first present the ESS model view and its
motivations for iDDS system. Then we will also present the iDDS schema,
architecture and the applications of iDDS.
