High rate packets transmission on ethernet LAN using commodity hardware

Abstract

Abstract-We report on measurements performed to test the reliability of high rate data transmission over copper Gigabit Ethernet for the LHCb online system. High reliability of such transmissions will be crucial for the functioning of the software trigger layers of the LHCb experiment, at the CERN's LHC accelerator. The technological challenge in the system implementation consists of handling the expected high data throughput of event fragments using, to a large extent, commodity equipment. We report on performance evaluations (throughput, error rates and frame drop) of the main components involved in data transmission: the Ethernet cable, the PCI bus and the operating system (the latest kernel versions of Linux). Three different platforms have been used.

Caracterización de canales de comunicación por tráfico y arquitectura de la red: una revisión<br />Characterization of communication channels in terms of traffic and network architecture: a review

“…Las herramientas para la captura de datos y análisis de la información comprenden modelos matemáticos y pruebas de datos reales que se relacionen con estos modelos, los cuales pueden ser ejecutados en modo simulado, de forma que los resultados deben evidenciar la presencia de errores que permitan diferenciarlos de los datos reales [28]. Otro parámetro utilizado para caracterizar un canal de comunicaciones es la tasa de transmisión [29], donde la medida del flujo de datos por el canal es obtenida con la herramienta ping, la cual determina el retardo de transmisión de los paquetes [30]. De la misma manera, se obtiene el RTT (Round Trip Time), el cual detalla el tiempo requerido por los paquetes para ir a su destino y retornar a su origen [31].…”

Fast online triggering in high-energy physics experiments using GPUs

“…Here the inefficient handling of the frame memory by the Linux driver constitutes a potential bottleneck, in particular for small-size (few hundreds Bytes) network packets at high rate (few hundred kHz). The issue can be solved with suitable memory management [18] in the kernel and driver code.…”

imCast: Studio-Quality Digital Media Platform Exploiting Broadband IP Networks

“…Secondly, an extremely tight inter-packet arrival time causes the proposed transport to confuse the or- der of packets. Poor timing granularity (e.g., 1 ms on the 2.6 kernel and 10 ms on the 2.4 kernel [32]) of Linux operating systems brings forth confusion, and the non-blocking select() or poll() function often yields mistakes.…”