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.
Primary 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)
