ATLAS TDAQ dataflow network architecture analysis and upgrade proposal

The real-time operation of the ATLAS dataflow system is highly dependent on the performance of the gigabit Ethernet network interconnecting its components (ap800 end nodes). After examining the functional and performance requirements of the network, several design alternatives (with respect to traffic repartition on core devices and available concentration technologies) are presented and analyzed. We introduce the use of 10 gigabit Ethernet as a flexible and simple technology for concentrating traffic. Network testing equipment as well as discrete model simulations is used to assess the performance of various implementation options. Based on performance, fault tolerance and flexibility considerations a preferred architecture is proposed for implementation