Globally Distributed Content Delivery

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Globally Distributed Content Delivery

• Presenter Baoning Wu
• 03/25/2003

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Motivation

• Flash crowd problem
• Overload can crash web sites and cause high
  response time
• Akamais system

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Akamais network infrastructure

• Allocate more servers to sites experiencing high
  load and serve all clients from nearby servers.
• The system directs client requests to the nearest
  available server likely to have the requested
  content.

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How to find servers?

• Dynamic DNS system

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Criteria for name servers to resolve IP address

• Service requested
• Server health
• Server load
• Network condition
• Client location
• Content requested

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DNS resolution

• A7.g.akamai.net
• Root name server -gt
• .net name server -gt
• .akamai.net name server(top level)-gt
• .g.akamai.net name server(low level)

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Network services

• Static content
• Use cache, apply lifetime
• Dynamic content
• Assemble dynamic content on edge server
• Streaming media
• Windows Media, Real, Apples QuickTime

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Challenges

• Scalability
• Must scale to many distributed servers
• Reliability
• Both hardware and software
• Software deployment
• Deploy new network software in stages

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Challenges (continue)

• Content visibility and control
• Cache consistency
• Lifetime control
• Authentication and authorization
• Integrity control
• Visibility into access patterns
• billing

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• Questions?