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March 2001 CBCB The Holy Grail: Media on Demand over Multicast Doron Rajwan CTO Bandwiz
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CBCB Outline Problems with broadband content on demand The caching (CDN) solution What about multicast? Bandwiz solution: Broadband Content on Demand Over Multicast Summary
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March 2001 CBCB The Challenge Broadband Content Delivery
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CBCB Content Delivery Infrastructure
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CBCB Unicast Content Delivery
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CBCB We are now entering the Broadband Era Unicast Content Delivery
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CBCB In the Broadband Era Unicast Content Delivery
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CBCB In the Broadband Era Unicast Content Delivery
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CBCB In the Broadband Era Unicast Content Delivery
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CBCB In the Broadband Era Unicast Content Delivery
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CBCB Current Situation Unicast Content Delivery
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March 2001 CBCB Content Delivery Networks: Content network, caching, delivery from the edge
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CBCB Moving Content to the Edge Directing requests to the Edge Content Delivery Networks
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CBCB Moving Content to the Edge also moves the problem.. to the edge
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CBCB Content Delivery Networks Again, a non scalable solution
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CBCB CDN: Moving Content to the Edge Requires: Control, re-direction, update Overcomes: Network link congestion Network equipment congestion Distance delay Does NOT solve: Edge server congestion Storage problems Bandwidth utilization
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March 2001 CBCB What About Multicast??
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CBCB IP Multicast
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CBCB Multicast is Scalable, but… Does not support browsing / on-demand Unidirectional “non interactive” protocol Congestion Reliability Not widely deployed ISP’s worry that the network may crash Inter-domain connectivity issues Multiple, complicated, routing protocols
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CBCB Bandwiz Solution Broadband Content Delivery On-Demand over Multicast
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CBCB Coding for asynchronous (on demand) content delivery
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CBCB Features Negligible receiver overhead (typically < 1%) Can be achieved with low computational complexity Encoder is flexible for ‘use optimization’ (file download or browsing) with a universal decoder Supports content “grouping” and differential decoding
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CBCB But what about Media Streaming? Basic delivery scheme above requires receiving the entire file prior to display Streaming solution: Data can be decoded on the fly, enabling streaming-on-demand Streaming performance defined by: Bandwidth at the sender Peak bandwidth at the receiver Latency Computational complexity Latency is reduced exponentially with increased bandwidth at the server
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CBCB Streaming On Demand Naïve solution – Carousel Today’s NVoD: N times bandwidth 1/N viewing latency Bandwiz Solution N times bandwidth 1/e^N viewing latency!!!
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CBCB 90 minutes movie 200 kbps real time bit-rate total file size of 135 MB Transmitter bandwidth1 Mbps1.5 Mbps Receiver peak bandwidth1 Mbps320 Kbps CPU utilization~3%~1% Latency from ‘ click ’ to view50 seconds45 seconds Streaming - Example
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CBCB Summary: Streaming On-Demand With ONLY 4 to 7 times the bandwidth of a single unicast transmission, and almost the same receiving bandwidth: Practically unlimited number of viewers Full screen quality viewing Most loss tolerant solution View from start when joining Short viewing latency (system parameter)
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CBCB Servers/Bandwidth Savings in both Unicast/Multicast Today’s Unicast Bandwiz Unicast Bandwiz Multicast Total Output Bandwidth 1 Gbps 12 mbps # of Servers (Pentium PC) >1021 Viewing Latency 10 sec30 sec 2-3 full feature 100 min. MPEG movies 1 mbps per stream 1000 simultaneous viewers with broadband modems
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CBCB Summary Multicast: Scalable, substantial resource savings However, unidirectional, non-interactive, same data to all receivers The Holy Grail: Use Multicast for On-Demand Delivery of Popular Content Streaming Solution: Optimal Tradeoff between Server Bandwidth and Delay
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March 2001 CBCB THANK YOU
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