大学間衛星ネットワークにおけるデータ共有  [in Japanese] Data-sharing on Inter-university Satellite Network  [in Japanese]

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Abstract

大学間教育交流ネットワーク「スペース・コラボレーション・システム」(SCS)の機能拡張としてデータ共有サービスを検討し,マルチキャスト・ファイル転送システムを開発した.データ共有サービスでは,VSAT(小型地球局)間のデータ共有を図ることにより,コンピュータ・ネットワークを用いた効果的な遠隔教育を目指している.SCSの特徴を十分に活かすため,特に映像音声を交換しているセッション中の資料伝送に焦点を絞り,回線制御装置との親和性を重視してシステムを設計した.これを各VSATに導入するには,既存の資源を有効活用しシステム的に柔軟性を備えることが重要である.そこで,既存画像符号化装置の信号多重化機能を利用し,データ伝送の回線速度帯域を選択できるようにした.実際に,VSATにファイル転送システムを実装し,ファイル転送実験を行うことによりファイル転送とこれにともなう各種機能の動作を確認した.実効伝送速度はオーバヘッドを考慮して実回線速度1.5? Mbpsのうち1.3? Mbpsのスループットを得,回線速度帯域を有効に利用していることを確認した.We developed a multicast file transfer system which is used for data-sharing services as extension of the inter-university satellite network (Space Collaboration System: SCS). With data-sharing among VSATs (Very Small Aperture Terminals), the service can provide an opportunity of effective distance education to SCS users in computer network. To make good use of SCS sufficiently, we focus on material transmissions during a session exchanging audiovisual signals, and develop the file transfer system connectedto the link control system. It is important to reuse present resources and to have systematic flexibility in installing the system to each VSAT. Then, signal multiplex function of a CODEC makes it possible to select a link-speed bandwidth. The developed system is actually implemented to the VSATs, and an experiment is made to evaluate its performance. The results show the smooth file transfers and works of each function. The transmission rate is obtained up to 1.3\,Mbps including headers in the link-speed of 1.5\,Mbps, which indicates efficient use of the link-speed bandwidth.

We developed a multicast file transfer system which is used for data-sharing services as extension of the inter-university satellite network(Space Collaboration System: SCS). With data-sharing among VSATs(Very Small Aperture Terminals), the service can provide an opportunity of effective distance education to SCS users in computer network. To make good use of SCS sufficiently, we focus on material transmissions during a session exchanging audiovisual signals, and develop the file transfer system connected to the link control system. It is important to reuse present resources and to have systematic flexibility in installing the system to each VSAT. Then, signal multiplex function of a CODEC makes it possible to select a link-speed bandwidth. The developed system is actually implemented to the VSATs, and an experiment is made to evaluate its performance. The results show the smooth file transfers and works of each function. The transmission rate is obtained up to 1.3Mbps including headers in the link-speed of 1.5Mbps, which indicates efficient use of the link-speed bandwidth.

Journal

  • Transactions of Information Processing Society of Japan

    Transactions of Information Processing Society of Japan 41(10), 2782-2793, 2000-10-15

    Information Processing Society of Japan (IPSJ)

References:  23

Cited by:  2

Codes

  • NII Article ID (NAID)
    110002725518
  • NII NACSIS-CAT ID (NCID)
    AN00116647
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    1882-7764
  • NDL Article ID
    5529805
  • NDL Source Classification
    ZM13(科学技術--科学技術一般--データ処理・計算機)
  • NDL Call No.
    Z14-741
  • Data Source
    CJP  CJPref  NDL  NII-ELS  IPSJ 
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