Content Delivery Networks

Patrick W. Gilmore patrick at
Tue Aug 7 00:08:06 UTC 2007

On Aug 6, 2007, at 5:10 PM, Rod Beck wrote:

> 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.

I am not sure why you would say Akamai is "tailored to pushing  
relatively small files", since I do not believe they say that  
anywhere.  LLNW does say they are focused on larger files.  (I  
believe LLNW claims Akamai is focused on smaller files, but do you  
believe what Akamai says about LLNW?)

I can confirm that Akamai does not have a backbone.  Neither does  
Panther Express, CacheFly, or Mirror Image.  While Level 3 (who owns  
Digital Island, which they bought from Savvis, who got that when they  
acquired Exodus, who bought way DI back when), LLNW, and at&t all  
have their own backbones.

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

Myriad.  Some are hard to overcome, some are very hard.  Keyword here  
being "scalable" - which you failed to define.  What is "scalable" to  
you?  100 Gbps?  500 Gbps?  The latter is medium-hard in the US, the  
former is nearly impossible in South Africa.

Which brings us to geography.  Are you US-centric?  European?   
Asian?  Six continents?  Just a few specific countries?

Plus, as you mention above, there's file size.  How about streaming  
vs. HTTP?  Optimize for latency or throughput?

Did I mention cost?

Etc., etc.

If someone asked "what are the major challenges in making scalable  
backbones?", how would you answer?


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