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Intelligent Caching and Packaging
in an ABR Multi-format CDN
Brian Tarbox
Distinguished Member of the Technical Staff
Moto...
Caching was not needed
when VOD was first launched
When VOD was in its infancy
• One central server supported an entire no...
EDGE CACHE
EDGE CACHE
EDGE CACHE
As VOD libraries grew, caching became key
Content grows
• Library with edge cache
• HD fo...
Caching Algorithms
Caching: predictive activity that
attempts to use past behavior to predict
future behavior
Critical dec...
LRU
CACHE
ORIGIN SERVER
CDN
With introduction of CDNs, caching is rolled
back to LRU
Content Explodes
• CDNs introduced
• ...
What affects predictability?
Diminishing Predictability
• Multiple formats
• Multiple bit rates
• nDVR unique copy
• Perso...
ORIGIN SERVER
CDN
EDGE CACHE
EDGE CACHE
EDGE CACHE
EDGE CACHE
CLUSTER
MANAGER
Intelligent Caching with affinity
By streami...
Comparison:
Intelligent Caching vs. LRU in CDN
Intelligent Caching
• Uses content affinity to intelligently
store chunks a...
Caching is also Affected by Packaging options
TRANSCODER PACKAGER ORIGIN CDN CLIENT
TRANSCODER PACKAGERORIGIN CDN CLIENT
T...
Thank You
Brian Tarbox
Distinguished Member of the Technical Staff
Motorola Mobility
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Intelligent Caching and Packaging in an ABR Multi-format CDN

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In a talk given to Nation Cable Television Association I describe a new model for caching and packaging content in an adaptive bit rate multi-format Content Delivery Network.

Published in: Engineering
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Intelligent Caching and Packaging in an ABR Multi-format CDN

  1. 1. Intelligent Caching and Packaging in an ABR Multi-format CDN Brian Tarbox Distinguished Member of the Technical Staff Motorola Mobility
  2. 2. Caching was not needed when VOD was first launched When VOD was in its infancy • One central server supported an entire node • Content was offered only in SD format • A library consisted of hundreds of titles • Caching was not necessary VOD SERVER
  3. 3. EDGE CACHE EDGE CACHE EDGE CACHE As VOD libraries grew, caching became key Content grows • Library with edge cache • HD formatted content • Thousands of titles • LRU evolves to Intelligent Caching ORIGIN SERVER
  4. 4. Caching Algorithms Caching: predictive activity that attempts to use past behavior to predict future behavior Critical decision in caching is determining what content to remove LRU removes content with oldest use time regardless of usage pattern Intelligent Caching tracks actual viewing time in the aggregate, discounting passive or initial viewing behavior Involves multiple dynamic parameters Draws statistical inferences on potential for future likelihood of additional views
  5. 5. LRU CACHE ORIGIN SERVER CDN With introduction of CDNs, caching is rolled back to LRU Content Explodes • CDNs introduced • Adaptive bit rate chunks • Millions of titles, billions of chunks • Caching algorithm reverts to LRU
  6. 6. What affects predictability? Diminishing Predictability • Multiple formats • Multiple bit rates • nDVR unique copy • Personalization – Targeted advertising – Blackout Enhancing Predictability • Content Affinity – Based on existence of many edge streamers – All stream requests for the same content are directed to the same edge streamer • Save disk space • Save bandwidth – Employs Cluster Manager to route content requests There are many influences on the predictability of future viewing of content
  7. 7. ORIGIN SERVER CDN EDGE CACHE EDGE CACHE EDGE CACHE EDGE CACHE CLUSTER MANAGER Intelligent Caching with affinity By streaming the same content from the same cache, the counts increase and network utilization is decreased
  8. 8. Comparison: Intelligent Caching vs. LRU in CDN Intelligent Caching • Uses content affinity to intelligently store chunks at the edge • Uses multiple parameters to assess true value of chunks stored at the edge • More efficient LRU Caching • No intelligence about content, its placement or its usage • Determines which chunks were least recently used and removes them CDN INTELLIGENT CACHE CLUSTER MANAGER EDGE SERVER EDGE SERVER CLIENT CLIENT CLIENT CLIENT EDGE SERVER EDGE SERVER CLIENT CLIENT CLIENT CLIENT EDGE SERVER EDGE SERVER CDN LRU CACHE
  9. 9. Caching is also Affected by Packaging options TRANSCODER PACKAGER ORIGIN CDN CLIENT TRANSCODER PACKAGERORIGIN CDN CLIENT TRANSCODER TRANS WRAPPERORIGIN CDN CLIENTCHUNKER Common, cacheable Personalized, not cacheable
  10. 10. Thank You Brian Tarbox Distinguished Member of the Technical Staff Motorola Mobility

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