What DNS Is Not

Jack Bates jbates at brightok.net
Tue Nov 17 04:11:09 UTC 2009

Glen Turner wrote:
> 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).

In some cases this may be true. However, many of the CDN's I've talked 
to will happily update which POP my network talks to. Is automatic 
detection perfect? Probably not. That is why they support manual 
correction. Their goal is to get you the best connectivity, and they 
usually don't have a problem, in my experience, working with a provider 
to ensure the right IP ranges go to the best POP.

 > 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.....

See above. It appears I have no problem expressing my policy to CDN's. 
Corporate world often uses views to express external and internal 
policy. Unfortunately, it's not that easy for the CDN, so they do the 
best that they can, and they correct when it's important enough for a 
provider to say "hey, this pop isn't the best for my network!"


More information about the NANOG mailing list