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Application-Level Network Performance / Measurement Tools

Application-Level Network Performance / Measurement Tools. Jason Leigh, Oliver Yu, Alan Verlo, Linda Winkler. Tele-Immersion is the synthesis of Virtual Reality, video conferencing, and advanced computation. Example of a Data Intensive Tele-Immersion Application.

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Application-Level Network Performance / Measurement Tools

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  1. Application-Level Network Performance / Measurement Tools Jason Leigh, Oliver Yu, Alan Verlo, Linda Winkler

  2. Tele-Immersion is the synthesis of Virtual Reality, video conferencing, and advanced computation

  3. Example of a Data Intensive Tele-Immersion Application • TIDE: Tele-Immersive Data Explorer • Collaborative Large Scale Data Visualization • In collaboration with National Center for Data Mining • General framework for collaborative visualization of massive data-sets • Current data-set is ozone data from NOAA

  4. Example of a Data Intensive Tele-Immersion Application • CIBRView: Collaborative Image BasedRendering Viewer • Cosmology Hydrodynamic code by Julian Borrill, LBNL/NERSC shows theoretical condensation of diffuse matter into string-like formations during early stages of universe evolution • Accesses volume data:512x256x256x 256 frames ~ 40Gig data-sets • Generates image slices that are distributed to collaborating clients • Sent about 500, 1M slices/filesfrom Chicago to Japan using parallelTCP. • It was also the application over whichwe tested DiffServ.

  5. Characteristics of Tele-Immersion Flows

  6. Motivation for Application-level networking tools • Bandwidth is becoming increasingly available. • Networking QoS is still under research and difficult to deploy and use. It is not as easy as “flipping a switch.” • Network QoS is not only about bandwidth, it’s about latency and jitter. • Applications today are not ready to use the extra bandwidth even if available. • Application developers have to be increasingly network savvy in order to be able to convert application requirements to networking services. • Need to make advanced networking easier for the average application developer. • Need to provide a higher level application framework to keep pace with network advances.

  7. Advanced Data Transport Techniques for Tele-Immersion • Maybe we can compensate for latency: • Reliable Low-Latency Data Transfer for Tele-Immersion • Even if you had QoS could you really take advantage of it? • High Throughput Techniques for Tele-Immersion

  8. Reliable Low-Latency Data Transfer for Tele-Immersion • In Tele-Immersion it is desirable to be able to transmit state information with minimum latency and jitter while preserving reliability • Rather than use TCP which uses acknowledgments to obtain reliability, try UDP augmented with error correction codes:Forward Error Correction

  9. ` goal FEC greatest benefit is in small packets. Larger packets impose greater overhead. As redundancy decreases FEC approaches UDP.

  10. G o a l

  11. Packet Loss over UDP vs FEC/UDP between Chicago & Amsterdam 50Mbps UDP or FEC +50Mbps UDP congestion

  12. High Throughput Techniques for Tele-Immersion • In Tele-Immersion it is desirable to share data files as rapidly as possible • Even if you had QoS, you couldn’t take advantage of it • Long Fat Network problem: an ftp session will max out at 3.5Mbps over a 100Mbps link between Chicago and Amsterdam (and Switzerland) • 2 Techniques: • Parallel TCP Socket Striping • Reliable Blast UDP

  13. Parallel Sockets : 64K Window SizeAmsterdam (SARA) to Chicago (EVL) Found it difficult to achieve more than 50Mbps on a 100Mbps link. Have been able to achieve 80Mbps on rare occasions.

  14. Reliable Blast UDP (RBUDP) • RBUDP - An old idea that may be useful now that networking bandwidth is increasing • Use UDP for bulk data transmission rather than TCP • If bandwidth can be guaranteed by QoS –reliability will be high- chances of errors will be few

  15. RBUDP Performance(EVL to SARA)

  16. RBUDP Performance(EVL to CERN)

  17. DiffServ results over a testbed between EVL and Argonne National Lab EVL 100Mbps 100Mbps x Cisco7507 25Mbps 80Mbps x fore 42Mbps 42Mbps ANL back x x 100Mbps 100Mbps + background + DiffServ Bandwidth recovery good 150ms 1-way latency Latency recovery not good Packet loss double

  18. Collaborative Coordination Experiments betweenChicago and Singapore • Tightly coordinated collaborative interaction task between 2 remote users • 200ms RTT is the threshold where performance begins to suffer • 200ms RTT with 0 jitter is same as 10ms RTT with 7ms jitter • So DiffServ is not suited for Tele-Immersion

  19. G2 is C++ toolkit for building Tele-Immersive applications with special emphasis on networking • G2 is the Grid’s main tele-immersion library • Networking: • UDP, TCP, Multicast, HTTP. • UDP reflector and multicast bridge. • TCP reflector. • Remote procedure calls. • 32 and 64bit Remote file I/O. • Parallel 32 & 64 bit TCP socket striping for high throughput data delivery. • FEC. • Client/Server distributed shared memory persistent database. • Threading, Mutual Exclusion. • Built-in Instrumentation of networking services.

  20. Tools for higher level application development: • Audio streaming • Articulated Avatars • VR navigation • VR menus • Speech recognition with IBM ViaVoice • Collaborative application shell to jumpstart development • Network visualization tools

  21. QoS Internet Monitoring ToolQoSIMoto • Provides real time viewing of CAVERNsoft data streams • Visualizes bandwidth, latency, jitter of multiple network flows • Accepts Netlogger compatible format

  22. These techniques are needed more than ever in STAR LIGHT • Being able to dedicate lambdas will ease our latency and jitter problems but we still can’t beat the speed of light. • Lambda switching requires more intelligence at the edges to perform traffic shaping, bandwidth management, error correction. • Need to provide high level API for applications to select Lambdas and define which application flow will go over the lambda. • Long Fat Network problems do not go away with GMPLS. • Need to provide a higher level application programmer’s framework to keep pace with network advances. We need more than just sockets( ) API.

  23. What new things can we do withSTAR LIGHT? • Streaming uncompressed high resolution stereoscopic 3D movies (1024x768x24bitsx30fps) ~ 1.05 Gbps • Imagine magnifying this to multi-tiled displays for ultra high resolution displays such as CAVEs and Active Murals

  24. What new things can we do withSTAR LIGHT? Distributed Tera-snap: • Perform a tera-mining correlation between distributed databases and generate a visual overview • 1 PC can absorb ~500Mbps => min 4.6 hours to perform a tera-snap • 20 PCs can absorb data and produce image composites in a min of 13 mins using 10Gbps

  25. What new things can we do withSTAR LIGHT? Digital Continuums: Distributed collaboratories with linked tiled, tele-immersive and mobile displays enhanced with cluster computing and data mining services

  26. Thanks • Thanks SARA (Amsterdam), CERN (Switzerland), IHPC (Singapore) for graciously participating in these network experiments • For more info: • www.evl.uic.edu/cavern • cavern@evl.uic.edu

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