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Re: [RRG] Why delaying initial packets matters



Hi Stig,

What follows are a bunch of questions based on DROPS and not DELAYS.
Well, this is still more or less speculation. I suppose what
should be done, is to study some common applications or
protocols and see what the effects would be. An obvious first
candidate would be DNS I think.

And Dave is just the guy for DNS ;-) My own limited understanding of DNS is that bind has a 5 second initial default timeout (from /usr/include/resolv.h) and that Windows XP has an initial timeout of 1 second, and then another 2 seconds. But this isn't the beginning and end of it. There are two potential complicating factors. First, not all applications use the OS resolvers. At one time I believe this was the case at least with Mozilla.

Keeping in mind that these queries are likely recursive, we shift our scrutiny to the name server. Supposing a query is dropped, will the next query go to the same name server or to another listed name server? If it's to another name server could that query also be dropped? Will behavior differ based on the number of zone cuts and whether the appropriate name servers are in the same proximity as the parent servers?

Can the application mitigate this issue by pre-caching queries? Some already do something like this but for different reasons. Dave's Tivo could do this when it receives EPG information, for instance.

Regards,

Eliot

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