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Jorg Liebeherr Department of Computer Science University of Virginia

Movie Delivery in the Internet - in 5 minutes -. Jorg Liebeherr Department of Computer Science University of Virginia. Interesting Issues. Streaming vs. Download Storage VBR vs. CBR class-level vs. flow-level QoS. Most media types:. have hardly real-time needs.

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Jorg Liebeherr Department of Computer Science University of Virginia

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  1. Movie Delivery in the Internet- in 5 minutes - Jorg Liebeherr Department of Computer Science University of Virginia

  2. Interesting Issues • Streaming vs. Download • Storage • VBR vs. CBR • class-level vs. flow-level QoS

  3. Most media types: • have hardly real-time needs • have hardly bandwidth needs • High-bandwidth media types with stringent QoS demand: • don’t exist in large numbers Interactive VR • don’t exist Web-style content videoconference Games Movies Telephony Live TV Control Media Types and their Demand high Bandwidth Demand low online(stringent) offline(less stringent) QoS Demand

  4. Traditionally, are handled via over-provisioning or simple (TOS-like) differentiation Unsubstantiated claim • Claim: For media delivery, most of the bandwidth will be consumed by “offline high-bandwidth” media types • Two ways to transmit these media: • Download • Streaming

  5. Download Time of an MPEG-2 Movie • 90 min @ 6 Mbps  approx. 4 GB Probably not of interest Duration of Movie Probably Streaming Download or Streaming Probably Download (1 Mbps) (1 Gbps) (1 Tbps)

  6. very fast (> 100 Gbps) download cache slow (< 10 Mbps) stream Download vs. Streaming • Operating point will be determined by available technology • QoS issues: • probably none for downloads in core network (due to high data rates) • probably none for down-stream streaming in access network (due to lack of contention for resources) • Key Issue: • Placement of content at the edges of the core network determines user-level latencies.

  7. Summary: Movie delivery in the Internet within 5 years • Classical QoS concepts may not be useful • Storage issues seem more important  Good target for QoS research • Disclaimer: The above comments do not apply to media types with stringent QoS demands: • telephony • games • control • interactive VR

  8. Streaming Media: How to deal with VBR traffic? • Add delay: Smoothing turns VBR into CBR traffic • Traffic theory: Statistical multiplexing theory tells us that aggregated VBR sources appear smooth • Economy of scale: If number of receivers is large, peak rate allocation is justifiable

  9. Class-level vs. flow-level QoS • This is a matter of desired effort of deployment and desired QoS: • Theoretical understanding of flow-level QoS is very good, and catching up for class-level QoS • Class-level QoS is useful to protect legacy traffic (best effort, TCP) • Problems (of both types of QoS): • QoS notions are revamped before they mature • The quality of commercial QoS implementations is insufficient

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