the holy grail: media on demand over multicast
DESCRIPTION
The Holy Grail: Media on Demand over Multicast. Doron Rajwan CTO Bandwiz. Outline. Problems with broadband content on demand The caching (CDN) solution What about multicast? Bandwiz solution: Broadband Content on Demand Over Multicast Summary. - PowerPoint PPT PresentationTRANSCRIPT
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The Holy Grail:The Holy Grail: Media on Demand over MulticastMedia on Demand over Multicast
Doron Rajwan
CTO
Bandwiz
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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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The Challenge
Broadband Content Delivery
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W eb H osting
N etwork A ccess P o in t (N A P )
A utonom ousN etworks
Backbone N etw ork ServiceProvider (N SP)
Backbone N etw ork ServiceProvider (N SP)
Local ISPEnd U sers
Local ISP
Local ISP
C ontent P rovider
R R
R
RR
R
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Content Delivery Infrastructure
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C ontent P rovider
R R
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W eb H osting
Unicast Content Delivery
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C ontent P rovider
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W eb H osting
We are now entering the Broadband Era
Unicast Content Delivery
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C ontent P rovider
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W eb H osting
In the Broadband Era
Unicast Content Delivery
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C ontent P rovider
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W eb H osting
In the Broadband Era
Unicast Content Delivery
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C ontent P rovider
R R
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W eb H osting
In the Broadband Era
Unicast Content Delivery
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Content ProviderWeb Hosting
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In the Broadband Era
Unicast Content Delivery
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C ontent P rovider
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W eb H osting
Current Situation
Unicast Content Delivery
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Content Delivery Networks:
Content network, caching, delivery from the edge
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C ontent P rovider
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W eb H osting
C ache
C ache
C ache
Moving Content to the Edge
Directing requests to the Edge
Content Delivery Networks
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C ontent P rovider
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W eb H osting
C ache
C ache
C ache
Content Delivery Networks
Moving Content to the Edge also moves the problem.. to the edge
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C ontent P rovider
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W eb H osting
Cache
Cache
Cache
Content Delivery Networks
Again, a non scalable solution
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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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What About Multicast??
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Web Hosting
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IP Multicast
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Web Hosting
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IP Multicast
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Web Hosting
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IP Multicast
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Web Hosting
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IP Multicast
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Web Hosting
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IP Multicast
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Web Hosting
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IP Multicast
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Web Hosting
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IP Multicast
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Web Hosting
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IP Multicast
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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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Bandwiz Solution
Broadband Content Delivery Broadband Content Delivery On-Demand over MulticastOn-Demand over Multicast
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Coding for asynchronous (on demand) content delivery
Encoder
O rig ina l D ata Encoded D ata
Decoder Decoder Decoder
O rig ina l D ata M issing D ata O rig ina l D ata
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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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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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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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90 minutes movie 200 kbps real time bit-rate total file size of 135 MB
Transmitter bandwidth 1 Mbps 1.5 Mbps
Receiver peak bandwidth 1 Mbps 320 Kbps
CPU utilization ~3% ~1%
Latency from ‘click’ to view 50 seconds 45 seconds
Streaming - Example
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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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Servers/Bandwidth Savings in both Unicast/Multicast
Today’s Unicast
Bandwiz Unicast
Bandwiz Multicast
Total Output Bandwidth
1 Gbps 1 Gbps 12 mbps
# of Servers (Pentium PC)
>10 2 1
Viewing Latency
10 sec 30 sec 30 sec
2-3 full feature 100 min. MPEG movies 1 mbps per stream 1000 simultaneous viewers with broadband modems
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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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THANK YOU