Speaker
Daniel Hugo Campora Perez
(CERN)
Description
The LHCb Online Network is a real time high performance network, in which 350 data sources send data over a Gigabit Ethernet LAN to more than 1500 receiving nodes. The aggregated throughput of the application, called Event Building, is more than 60 GB/s. The protocol employed by LHCb makes the sending nodes transmit simultaneously portions of events to one receiving node at a time, which is selected using a credit-token scheme. The resulting traffic is very bursty and sensitive to irregularities in the temporal distribution of packet-bursts to the same destination or region of the network.
In order to study the relevant properties of such a dataflow, a non-disruptive monitoring setup based on a networking capable FPGA (NetFPGA) has been deployed. The NetFPGA allows order of hundred nano-second precise time-stamping of packets. We study in detail the timing structure of the Event Building communication, and we identify potential effects of micro-bursts like buffer packet drops or jitter.
Authors
Daniel Hugo Campora Perez
(CERN)
Gianni Antichi
(Department of Information Engineering, University of Pisa)
Guoming Liu
(CERN)
Marc Bruyere
(1 CNRS, LAAS, 2 Université de Toulouse, LAAS, 3 DELL Inc)
Co-authors
Andrew Moore
(University of Cambridge)
Niko Neufeld
(CERN)
Philippe Owezarski
(1 CNRS, LAAS, 2 Université de Toulouse, LAAS)
Stefano Giordano
(Department of Information Engineering, University of Pisa)
