Re: DNS Anycast as traffic optimizer?

[Steve Francis <sfrancis () fastclick com>]

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
>
>
>