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Re: DNS Anycast as traffic optimizer?
Bill Woodcock wrote:
Oops, sorry, misread the question. I should have said "I expect there is research..." I was answering why I wanted to know, not why I expect there is research...On Wed, 1 Sep 2004, Steve Francis wrote: >>> I'm sure there is research out there... >> Why? :-) > Usual - if I build it myself, will it work well enough, or should I pony > up for a CDN?
Excellent point, thanks.> I thought it was standard best practice for availability, like for root > name servers. I thought it was not a good "closest server" selection > mechanism, as you'll be going to the closest server as determined by BGP > - which may have little relationship to the server with lowest RTT.
So there is no need to anycast the DNS servers and rely on BGP topology for selection.
Instead use bind's behaviour so that each resolving nameserver will be querying the authoritative nameserver that responds the fastest.
If I have inconsistest replies from each authoratitive name server, where each replies with the virtual IP of a cluster colocated with it, I will have reasonably optimised client's nameserver to web farm RTT.
Whether that is good for the client, remains to be seen, but it seems to be all that (most) commercial CDNs do.
That just makes it too easy....
Am I missing something else, or is it really that simple to replicate a simple CDN?