Return to the PREVIOUS PAGEObjective: The objectives of the ACTS/Keck GCM experiment are to (1) demonstrate distributed supercomputing (meta-supercomputer) over a high performance satellite link, (2) demonstrate remote science data gathering, control, and analysis (telescience) with meta-supercomputer resources using multiple satellite hops, and (3) determine optimum satellite terminal/supercomputer host network protocol design to for maximum meta-supercomputer efficiency.
Approach: The two ACTS experiments, Keck and GCM, will be led by JPL and GSFC, respectively, with support from Caltech, UCLA, GWU, and Hawaii PacSpace. The GCM experiment will require a virtual channel connection between the JPL Cray T3D and the GSFC Cray C90, while the Keck experiment will require a virtual channel connection between a remote control room at Caltech in Pasadena, CA, and the Keck Observatory local area network on Mauna Kea, Hawaii. Based on the expected availability of network switch and host ATM SONET OC-3 equipment by early CY95, ATM was selected as the base transport mechanism. This greatly simplifies the terrestrial network infrastructure, especially in the Hawaiian islands and ATDnet. A striped (4X OC-3) HIPPI/SONET gateway will be used as a backup should all the ATM infrastructure not be available by early CY95. For Keck, Caltech will modify the graphical user interface (GUI) design for use over longer delay channels and multi-user/location control (an adaptation of one currently used), JPL will perform the network system engineering and atmospheric/fading BER analysis, and GWU the HDR site design and performance modeling. Additionally, PacSpace will assist with scheduling the use of the Honolulu HDR and engineering the Honolulu/Mauna Kea network infrastructure. For GCM, GSFC will lead the porting of the distributed global climate model to the JPL and GSFC Cray supercomputers. GSFC staff scientists will port the Poseidon OGCM and Aries AGCM codes for coupling with UCLA AGCM and GFDL OGCM codes. In both experiments, the effect of fading, burst noise, and long transit delays will be examined and compared against lower error rate terrestrial links.
Accomplishments: During the past year, the project wide proposal was written (Aug. 93) and later revised (in Jan 94) to reflect later HDR delivery. In Dec. 93, the overall network infrastructure was refined to include ATM, and in May 94, the Hawaiian "last mile" fiber/microwave network infrastructure design was completed. In Jul. 94, JPL completed a atmospheric fading model and GSFC completed an integrated ATDnet network design that permits ATM, HIPPI, and raw SONET connectivity to NASA and ARPA experiment users.
Significance: This pair of experiments will demonstrate the feasibility of using long path delay satellite links to establish meta-computing and control/data acquisition networks for remote collaboration, observation, and control of science experiments in hostile environments. Examples include Antarctic and undersea exploration, petroleum exploration, and interconnecting data centers to share large data bases.
Status/Plans: Both applications will be designed, ported, and debugged over low speed Internet connections during the next year. Full HDR deployment and network connectivity is expected by Jul. 95, at which time high bandwidth trials are expected to commence, lasting for 9 additional months (to Mar 96).
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