Operation and performance of an ATM based demonstrator for the sequential option of the ATLAS trigger

This paper describes an implementation on a small scale demonstrator of the sequential option for the ATLAS trigger. This demonstrator is built around an ATM switch connecting source modules, destination processors, a supervisor and a monitor. The source modules emulate a group of detector read-out buffers. We describe the hardware and software architecture of the system. We investigate the performance of the demonstrator in various configurations and with different sets of input parameters. Finally, we discuss the scaling of the results to the design of a large trigger system for ATLAS.