Re: DNS Anycast as traffic optimizer?

[Steve Francis]

Bill Woodcock wrote:
     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?

   > ...how good/bad using DNS anycast is as a kludgey traffic optimiser?
I'd hardly call it a kludge.  It's been standard best-practice for over a
decade.
 

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.
It'd be nice to see some metrics wither way....

   > THe question is, what is that "some" relationship?  80% as good as
   > Akamai?  Terrible?
Should be much higher than Akamai, since that's not what they're
optimizing for.  If you want nearest server, anycast will give you that
essentially 100% of the time.  Akamai tries to get queries to servers that
have enough available capacity to handle the load.  Since they're handling
bursty, high-bandwidth applications, rather than DNS.
                               -Bill