L. R. Cottrell

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This paper presents pathChirp, a new active probing tool for estimating the available bandwidth on a communication network path. Based on the concept of “self-induced congestion,” pathChirp features an exponential flight pattern of probes we call a chirp. Packet chips offer several significant advantages over current probing schemes based on packet pairs or(More)
SLAC has been studying end-to-end WAN bandwidth availability and achievability for 2.5 years via IEPM-BW [1]. IEPM-BW performs network intensive tests every 90 minutes. Based on that experience we have also developed a light weight available bandwidth (ABwE [2]) measurement tool that can make a measurement within a second. We are now extending this to a WAN(More)
This document describes a standard set of network characteristics that are useful for Grid applications and services as well as a classification hierarchy for these characteristics. The goal of this work is to identify the various types of network measurements according to the network characteristic they measure and the network entity on which they are(More)
Understanding how the Internet is used by HEP is critical to optimizing the performance of the inter-lab computing environment. Typically use requirements have been defined by discussions between collaborators. However, later analysis of the actual traffic has shown this is often misunderstood and actual use is significantly different to that predicted.(More)
Many grid computing applications require massive data transfers for distributed analysis. Knowledge of network properties like the available bandwidth along the communication paths between grid nodes can reduce data transfer times and improve scheduling of grid computing tasks thereby enhancing performance. This paper presents pathChirp, a light-weight(More)
Large, distributed High Energy Physics (HEP) collaborations, such as D0, CDF and US-CMS, depend on stable and robust network paths between major world research centres. The evolving emphasis on data and compute Grids increases the reliance on network performance. Fermilab's experimental groups and network support personnel identified a critical need for WAN(More)
The Digital Divide prevents Africa from taking advantages of new information technologies. One of the most urgent priorities is to bring the Internet in African Universities, Research, and Learning Centres to the level of other regions of the world. eGY-Africa, and the Sharing Knowledge Foundation are two bottom-up initiatives by scientists to secure better(More)
The first panel member will present “Employment Trends in Computer Occupations”. This is a preview of a forthcoming Bureau of Labor Statistics Report on the same subject. It is the result of several years of research on employment issues in the field of data processing given by the head of the research team, Mr. Patrick Wash, Supervisory Labor(More)
The bold network challenges described in ”Internet End-to-end Performance Monitoring for the High Energy and Nuclear Physics Community” presented at PAM 2000 have been tackled by the intrepid administrators and engineers providing the network services. After less than a year, the BaBar collaboration has collected almost 100 million particle collision events(More)