What DNS Is Not

Glen Turner gdt at gdt.id.au
Mon Nov 16 20:31:41 CST 2009


On 10/11/09 01:58, Jack Bates wrote:
> And different CDN's behave differently, depending on how they deliver
> content, support provider interconnects, etc. I'd hardly call many of
> them DNS lies, as they do resolve you to the appropriate IP, and if that
> IP disappears, try and quickly get you to another appropriate IP.

It depends what you mean by "appropriate".  It may not be "least cost"
or "closest", and that can be a rude shock when the CDN traffic suddenly
costs you A$5/GB (delivered from the US by undersea cable) rather than
$0 (delivered from an in-country peer).

DNS is the wrong answer, simply because there's no way for the user to
express *their* policy.  But since there no CDN support in HTTP.....

-- 
  Glen Turner   <http://www.gdt.id.au/~gdt/>




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