Content Delivery Networks

Michal Krsek michal at
Tue Aug 7 07:59:41 UTC 2007

Content Delivery NetworksRod,
I run a small CDN oriented to audio/video distribution in Central Europe region. You mentioned challenges that CDN are facing. There are several of these:

1) Geographic load distribution
- in example, you have to have enough capacity in each distribution area that is being potentionally served by your customers (media companies).
2) Computing power
- you have to have in each POP adequate computing power that allows you to use full bandwidth available in that POP
3) Network capacity in each POP
- self explaining
4) Content moving
- you have to optimise internal data flows between POPs
5) User redirection
- You have to implement a scalable mechanisms that redirects users to the closes POP. You can use application redirect (fast, but not so much scalable), DNS redirect (scalable, but not so fast) or anycasting (this needs cooperation with ISP).
6) Costs of the system
- Most CDNs are designed for peaking traffic, but load is more dynamic that in traditional networks.
7) Play alone
There is almost no way for handover traffic to other CDN. No standards, no kinf of interconnection agreement.

These points are only a rough overview, this ecosystem is developping and challenges also depend on the starting conditions and region where you are running you CDN.


  ----- Original Message ----- 
  From: Rod Beck 
  To: Jason J. W. Williams ; Pekka Savola ; Robert Boyle 
  Sent: Monday, August 06, 2007 23:10
  Subject: Content Delivery Networks

  Can anyone give a breakdown of the different kinds of content deliver networks? For example, we have Akamai, which appears to be a pure Layer 3 network that is tailored to pushing relatively small files like web pages and we have Lime Light Networks, which is a mix of Layer 1 and Layer 3, that focuses on bigger files like video streams.

  Any insights out there? And what are the major challenges in making scalable content delivery networks?

  Roderick S. Beck
  Director of EMEA Sales
  Hibernia Atlantic
  1, Passage du Chantier, 75012 Paris
  Wireless: 1-212-444-8829.
  Landline: 33-1-4346-3209
  AOL Messenger: GlobalBandwidth
  rod.beck at
  rodbeck at
  ``Unthinking respect for authority is the greatest enemy of truth.'' Albert Einstein.

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