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Integration of VSI-E into Operation Systems

This document discusses the history, characteristics, modes, and tasks of VSI-E, a system proposed to simplify data exchange between VLBI systems of different countries. It covers the goals, documentation, software, and architecture of VSI-E, as well as its characteristics and modes. The conclusion highlights ongoing testing and integration efforts.

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Integration of VSI-E into Operation Systems

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  1. Integration of VSI-E into Operation Systems Alan Whitney awhitney@haystack.mit.edu Chester Ruszczyk chester@haystack.mit.edu 4th e-VLBI Workshop, Sydney, Australia Wed. July 13, 2005

  2. Agenda • VSI-E History / Characteristics • VSI-E Modes • VSI-E Tasks • Conclusion

  3. VSI-E History • VSI-E proposed to simplify the exchange of data between the VLBI systems of different countries. • e-VLBI Workshop Dwingeloo 2003 • First discussion on VSI-E • Goals • Efficient transport mechanism • Standard protocols • Internet-friendly transport

  4. VSI-E History • Goals (cont) • Scalable Implementation • Ability to transport individual data-channel streams as individual packet streams • Ability to make use of multicasting • to transport data and/or control information in an efficient manner • could be used in the future for support of distributed correlation

  5. VSI-E History • RTP proposed for transport of VSI-E data • RTP has wealth of implementation and operational experience • RTP seen as internet-friendly by the network community. Attention to: • Efficiency, • Resource constraints, • Scaling issues

  6. VSI-E Documentation and Software • VSI-E Draft release 2.7, January 30, 2004 • http://evlbi.haystack.mit.edu/twiki/pub/EVLBI/WebDocs/VSI-E-2-7.pdf • Reference implementation library and application (vtp) release 1.0, October 5th, 2004 • http://evlbi.haystack.mit.edu/twiki/bin/views/EVLBI • Linux, BSD - based

  7. VSI-E Characteristics - RTP • Framework for transporting real-time data • Timing and synchronization • Merging, bridging, and translation support • Application-specific control data • e.g. PDATA, time, data collection parameters, antenna pointing, system temperature • Real-time / non-real time transfers • Transport protocol independent • Multicast support • Data rates up to 100Gbps

  8. VSI-E Characteristics (RTCP) • RTP Control Protocol • Monitors network’s real-time performance • Statistics collected from receivers • Information delivered to • Senders • adapt to prevailing conditions • Network management • identifies faults, provisioning problems • Adaptive, bandwidth-limited design

  9. VSI-E Architecture

  10. VSI-E Modes • Real-time • Buffer to buffer • Non-Real Time • File to File or Disk • “File” is used as temporary storage • Disk to Disk or File • Pseudo Real Time • Disk to Buffer • File to Buffer

  11. Pseudo Real-Time Operation • Ability to take stored data (disk or file mode) • Source Stations • Network attached storage on the network • Storage Depot • Create connection to Correlator • Correlate the data • File2net – Net2In • Disk2net – Net2In • Advantageous • Demos • Disks

  12. VSI-E Tasks • Draft • RTP Profile for IETF • E-VLBI Specific • Transport Protocol • Guidelines and profiles • Various transport alternatives. • Conversion into VSI-E format • VTP -1.0.H (Mark5 specific) • Development of efficient translation modules • Development of efficient packetization algorithms • Support for different transport protocols inherent in application, but not dynamic

  13. Conclusion • VSI-E Testing • Test bed between • Haystack and Kashima • K5 Source to Mark5 Correlator • Transport protocol evaluation (UDP/TCP) • VSI-E planned to be demonstrated • Super Computing 05 (November) • Participants: Europe, Japan, US • Correlated at Haystack • Fringes sent live to Seattle • Integration to resource allocation scheme

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