CMS DAQ Event Builder Based on Gigabit Ethernet
G. Bauer, Vincent Boyer, J. G. Branson, A. M. Brett, Eric Cano, Andrea Carboni, Marek Ciganek, S. Cittolin, S. Erhan, D. Gigi, Frank Glege, Robert Gómez-Reino, M. Gulmini, E. Gutierrez Mlot, Johannes Gutleber, C. Jacobs, J. C. Kim, Markus Klute, E. Lipeles, Juan Antonio Lopez Perez · IEEE Transactions on Nuclear Science · 2008
The CMS data acquisition system is designed to build and filter events originating from 476 detector data sources at a maximum trigger rate of 100 kHz. Different architectures and switch technologies have been evaluated to accomplish this purpose. Events will be built in two stages: the first stage will be a set of event builders called front-end driver (FED) builders. These will be based on Myrinet technology and will pre-assemble groups of about eight data sources. The second stage will be a set of event builders called readout builders. These will perform the building of full events. A single readout builder will build events from about 60 sources of 16 kB fragments at a rate of 12.5 kHz. In this paper, we present the design of a readout builder based on TCP/IP over Gigabit Ethernet and the refinement that was required to achieve the design throughput. This refinement includes architecture of the readout builder, the setup of TCP/IP, and hardware selection.