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e-VLBI Application Performance and Characteristics

e-VLBI Application Performance and Characteristics. Wednesday September 29, 2004. e-VLBI Application and Architecture. VLBI Data Loss and delay tolerant Real-time Sustained, high bw flows Astronomy: 10 stations@1Gbps , 24 hours/day, 10 days = 1.1 PetaBytes!. e-VLBI Antenna Connectivity.

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e-VLBI Application Performance and Characteristics

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  1. e-VLBI Application Performance and Characteristics Wednesday September 29, 2004

  2. e-VLBI Application and Architecture VLBI Data Loss and delay tolerant Real-time Sustained, high bw flows Astronomy: 10 stations@1Gbps, 24 hours/day, 10 days = 1.1 PetaBytes!

  3. e-VLBI Antenna Connectivity • E-VLBI Experiments • Westford, MA: 1 Gbps (soon 10 Gbps) • NASA GGAO, MD: 1 Gbps (soon 2.5 Gbps) • Onsala, Sweden: 1 Gbps • Kokee Park, HI: 155 Mbps • Wetzell, Germany: 34 Mbps • Kashima, Japan: 1 Gbps • Koganei, Japan: 1 Gbps • Tsukuba, Japan: 622 Mbps • TIGO, Chile: 1.5 Mbps

  4. Typical e-VLBI Data Requirements • Timeliness: • Some astronomy experiments: months • Rapid Turnaround: weeks • UT1: days • Real-time (diagnostics, tracking): sub-second-seconds • Loss: • 5-10% of data

  5. Issues • What can applications do to make better use of network? • Track/determine network performance • Vary transmission strategy according to network performance • Application environment also important (e.g. tuning) • Can standard application interfaces (sockets) and/or protocols be created to assist network in classifying and optimizing applications? • APIs that allow applications to choose and modify transport protocols according to network type and network performance would be useful • Also useful to provide application with access to real-time and historical network performance

  6. Our Approach • Intelligent End Systems • Dynamic transmission strategy • Scheduling • Selective marking/discard (e.g. QBSS) • Resource Reservation • Integrated application/network monitoring • Historical (iperf, nuttcp, bwctl, nsdb) • Real-time (RTCP) • Seamless matching of transport protocol to network • Application level: TCP, UDP, UDT, … • Kernel level: Reno TCP, FAST TCP, HSTCP, Westwood, BICC, Vegas, … • Development of library for application development • VLBI Socket Library (V1.0 in beta) • Development of applications for scientists • Experiment Guided Adaptive Endpoint • High-level profile that allows scientists to specify application requirements  application transmission strategy/behavior

  7. Architecture

  8. Thank you David Lapsley dlapsley@haystack.mit.edu

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