What DNS Is Not

David Andersen dga at cs.cmu.edu
Mon Nov 9 00:42:18 UTC 2009

On Nov 8, 2009, at 7:30 PM, bmanning at vacation.karoshi.com wrote:

> On Sun, Nov 08, 2009 at 07:17:16PM -0500, David Andersen wrote:
>> "Our trace-driven simulations yield two findings. First, reducing the
> 	            -----------
>>  -Dave
> 	a simulation is driven from a mathmatical model, not real world
> 	constructions.

Hi, Bill -

The paper is worth reading.

"The paper also presents the results of trace-driven simulations that  
explore the effect of varying TTLs and varying degrees of cache  
sharing on DNS cache hit rates. "

emphasis on *trace-driven*.  Now, you can argue whether or not their  
traces are representative (whatever that means) -- they used client  
DNS and TCP connection traces from MIT and KAIST, so it definitely has  
a .edu bias, iff there is a bias in DNS traffic for universities vs.  
"the real world", but to the extent that their traces represent what  
other groups of users might see, their evaluation seems accurate.


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