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Network Models for Distance Education Dissemination

Network Models for Distance Education Dissemination. Saraswathi Krithivasan Sridhar Iyer IIT Bombay. ICDE, December 2005. Introduction. Disseminating educational content to remote locations. Educational Multimedia content Size of files Nature of transmission

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Network Models for Distance Education Dissemination

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  1. Network Models for Distance Education Dissemination Saraswathi Krithivasan Sridhar Iyer IIT Bombay ICDE, December 2005

  2. Introduction Disseminating educational content to remote locations • Educational Multimedia content • Size of files • Nature of transmission • Network mechanisms available • Satellite-based: EDUSAT, VSAT network (IITB) • Terrestrial links: Leased lines • Private networks: Intranet • Public networks: Internet

  3. Goal of distance education Reaching participants at remote locations by intelligently exploiting existing technology Parameters considered: -- Reach -- Scalability -- Cost effectiveness -- Flexibility

  4. Our Focus Analysis of various network models and their suitability to different user groups and reach • User groups • Educational institutions • Governmental agencies • Business organizations and industry • Individual users • Reach • Within the country • Across the globe

  5. SS SRS SRS Satellite based models Model 1: VSAT model A multicast client group -- connected through dedicated links -- served by a Single Service Provider -- Live-interaction possible SS: Source Site SRS : Satellite Receiving Site

  6. Satellite based modelsModel 1: VSAT model • Advantages: • Reach: Anywhere within a region • Scalability • Cost effectiveness • Interaction • Disadvantages • Inflexible: Space, Time • Traveling overhead • High initial investments

  7. SS SRS1 SRS2 Via LL Via satellite LLSR1 LLSR2 Satellite based models Model 2: A Hub and spoke model • Several centers within a city • Sharing of initial infrastructure cost SS: Source Site SRS : Satellite Receiving Site LLSR: Leased Line Receiving Site

  8. A Hub and spoke model • Advantages: • Reach • Scalability • Cost effectiveness • Interaction • Disadvantages • Inflexible: Space, Time • Traveling overhead • Hub: Single point of failure: Reliability? • Recurring annual costs

  9. Streaming models Model 3: Basic streaming model • Synchronous streaming • Flexibility in space • Encoded content stored for future use • On demand streaming • Flexibility in time and space • Access based on user convenience Encoded file I Internet Source Site ISP’s Data Center

  10. Basic Streaming model • Advantages: • Flexibility • Users need only a standard player that supports streaming • Disadvantages • No guarantee on quality • Scalability is questionable

  11. PoP PoP Streaming models Model 4: Caching model SS: Source Site LL: Leased Line ISP: Internet Service Provider PoP: Point of Presence Via LL Streaming server SS ISP’s backbone ISP • Cache servers at PoP • QoS to users by serving from local caches

  12. Caching model • Advantages: • Flexibility • Users need only a standard player that supports streaming • Improved quality through local provisioning • Disadvantages • Cache maintenance and management

  13. Via satellite SS SRS1 PoP SRS2 PoP Hybrid models Model 2: A two-tier model • Leveraging existing satellite network to load local caches • Improved QoS to local participants SS: Source Site SRS : Satellite Receiving Site PoP: Point of Presence

  14. Two-tier model • Advantages: • Flexibility • Users need only a standard player that supports streaming • Improved quality through local provisioning • Leveraging existing technology • Disadvantages • Cache maintenance and management • Additional cost of transfer from SRS to PoP

  15. Hybrid models Model 2: A three-tier model Leveraging existing satellite network to load local caches to serve corporate Intranets Via satellite SRS1 PoP SS Intranet SRS2 PoP SS: Source Site SRS : Satellite Receiving Site PoP: Point of Presence

  16. Three-tier model • Advantages: • Flexibility • Users need only a standard player that supports streaming • Improved quality through local provisioning • Leveraging existing technology • Cost of transfer from SRS to PoP can be spread across corporations • Disadvantages • Cache maintenance and management • Cooperationbetween entities

  17. Mapping users to models

  18. Summary • Network models which combine satellite, terrestrial, private, and public networks are proposed. • Advantages and disadvantages of deploying such models are outlined. • Given the user’s requirements and reach of the content, suitable models are recommended.

  19. FUTURE : GLOBAL REACH ? Thank you!Your comments will be greatly appreciatedemail: saras@it.iitb.ac.in

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