Integration of VSI-E into Operation Systems

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Integration of VSI-E into Operation Systems

• Chester Ruszczyk
• chester_at_haystack.mit.edu

Alan Whitney awhitney_at_haystack.mit.edu
4th e-VLBI Workshop, Sydney, Australia Wed. July
13, 2005
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Agenda

• VSI-E History / Characteristics
• VSI-E Modes
• VSI-E Tasks
• Conclusion

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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

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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

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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

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VSI-E Documentation and Software

• VSI-E Draft release 2.7, January 30, 2004
• http//evlbi.haystack.mit.edu/twiki/pub/EVLBI/WebD
  ocs/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/EVLB
  I
• Linux, BSD - based

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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

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VSI-E Characteristics (RTCP)

• RTP Control Protocol
• Monitors networks 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

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VSI-E Architecture
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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

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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

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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

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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