create new tag
, view all tags



Two example applications, which are currently being integrated into the DRAGON network, include electronic Very Long Baseling Interferometry (eVLBI) and High Definition Collaboration and Visual Area Networking (HD-CVAN).

A brief introduction to each is presented below.

Radio Astronomy: e-VLBI

Very-Long-Baseline Interferometry (VLBI) has been used by radio astronomers for more than 30 years as one of the most powerful techniques for studying objects in the universe at ultra-high resolution and measuring earth motions with ultra-high accuracy. VLBI allows images of distant radio sources to be made with resolutions of tens of microarcseconds, far better than any optical telescope. VLBI also provides a stable inertial reference frame formed by distant quasars to study the motions of the Earth in space with exquisite precision, revealing much information about both surface and internal motions of the Earth system, including interactions with the dynamic motions of the atmosphere and oceans.

VLBI combines data simultaneously acquired from a global array of up to ~20 radio telescopes to create a single coherent instrument. Traditionally, VLBI data are collected at data rates close to ~1 Gbps on magnetic tapes or disks that are shipped to a central site for correlation processing. Work has begun to utilize modern global high-speed networks to faciliate this process and potentially develop important new capabilites such as real-time data correlation and analysis and scientific returns.

The advanced capabilities of the DRAGON infrastructure will be utilized to greatly increase the timeliness, quality, and raw bandwidth of data flow from the radio telescopes to the correlator sites. The DRAGON network will include connections to NASA GSFC Goddard Geophysical and Astronomical Observatory (GGAO), U.S. Naval Observatory (USNO) in Washington, D.C., and the MIT Haystack Observatory. The ability of the DRAGON infrastructure to dynamically provision guaranteed resources will be used to establish an e-VLBI application specific topology which can be scheduled in advance, provisioned in seconds, and provide guaranteed end-to-end QoS.

High Definition Video Applications: HD-CVAN

The goals of the High Definition Collaboration and Visual Area Networking (HD-CVAN) application are to utilize the DRAGON network to enable advanced capabilities in the areas of high definition format conferencing and the remote display and steering of visualization outputs.

The key features of the DRAGON network which will be exploited are the ability to form application specific topologies of guaranteed resources and the abilty to transmit data in a protocol agnostic format. The ability to transmit in a protocol agnostic manner is a result of the all optical nature of the DRAGON network. This will allow minimum latency networking which is critical to enable these interactive applications.

UltraGrid: A High Definition Collaboratory

The goals of the UltraGrid project are to enhance the state of the art in high quality, large scale, telepresence systems and to enable flexible and ad-hoc remote collaboration.

The UltraGrid video conferencing system enables high-definition (HD) interactive video conferencing with minimal latency. UltraGrid, supports full rate uncompressed HD video at over 1.2 Gbps. In combination with AccessGrid, UltraGrid provides a complete HD video conferencing experience, utilizing AccessGrid's venue server infrastructure and audio services.

The UltraGrid system can also be utilized as a general purpose HD data distribution system. UltraGrid nodes convert SMTPE 292M high-definition video signals into RTP/UDP/IP packets which can then be distributed across a variety of network infrastructures. UltraGrid's architecture seeks to minimize system induced latency. This enables UltraGrid to be utilized for a variety of real-time applications which are latency sensitive such as video conferencing and real-time interactive 3D visualization.

For uncompressed HD, UltraGrid operates in two different modes: one at just under 1 Gbps (for environments limited to 1 Gbps transport) and another at full rate HD mode of over 1.2 Gbps. UltraGrid also supports video compression schemes, including standard definition Digital Video (DV) and Motion JPEG.

Uncompressed HDTV over IP, GigE environment

Uncompressed HDTV over IP

  • Not truly HDTV — color is subsampled to 8bits
  • Performance is at the mercy of best-effort IP network
  • UltraGrid processing introduces some latency

All-optical, Low Latency High Definition Collaboration

All-optical HD-CVAN

  • End-to-end native SMPTE 292M transport
  • Media devices are directly integrated into the DRAGON environment via proxy hosts
    • Register the media device (camera, display, ...)
    • Sink and source signaling protocols
    • Provide Authentication, authorization and accounting.

Topic revision: r8 - 2014-04-07 - XiYang
This site is powered by the TWiki collaboration platform Powered by Perl Copyright 1999-2021.
The information contained in these pages is the property of the Mid-Atlantic Crossroads (MAX).
If you have questions or comments, please contact WebBottomBar">MAX Administration