An event builder network for LHCb upgrade and the simulations on its performance

The LHCb experiment is considering an upgrade towards a trigger-free Data Acquisition (DAQ) system. All detector information will be readout at full collision rate (40 MHz) and sent to a large processing farm which performs event building and filtering. According to the physics simulation result, the DAQ system requires a large event builder network (also called DAQ network) with an aggregate bandwidth more than 34 Tb/s.

In this paper we present a new architecture of the event builder network, which is a multistage network using low-cost 10-Gigabit Ethernet switches. To evaluate the performance of the full scale system, several simulations have been done. This paper describes different DAQ protocols and the simulation developed for the event builder network based on the framework OMNeT++. The buffer occupancy of the switches has been studied.