North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: That MIT paper
On Thu, Aug 12, 2004 at 01:35:36PM +0200, Niels Bakker scribed: > > * [email protected] (David G. Andersen) [Thu 12 Aug 2004, 02:55 CEST]: > > Global impact is greatest when the resulting load changes are > > concentrated in one place. The most clear example of that is changes > > that impact the root servers. When a 1% increase in total traffic > > is instead spread among hundreds of thousands of different, relatively > > unloaded DNS servers, the impact on any one DNS server is minimal. > > And since we're talking about a protocol that variously occupies less than > > 3% of all Internet traffic, the packet count / byte count impact is > > negligible (unless it's concentrated, as happens at root and > > gtld servers). > > This doesn't make sense to me. You're saying here that a 1% increase in > average traffic is a 1% average increase in traffic. What's your point? > > if a load change is concentrated in one place how can the impact be > global? Because that point could be "critical infrastructure" (to abuse the buzzword). If a 1% increase in DNS traffic is 100,000 requests per second (this number is not indicative of anything, just an illustration), that could represent an extra request per second per nameserver -- or 7,000 more requests per second at the root. One of these is pretty trivial, and the other could be unpleasant. > At root and gTLD servers I assume DNS traffic occupies significantly > more than 3% of all traffic there. Still, a 1% increase remains 1%. Sure, but the ratio still plays out. If your total traffic due to DNS is small, then even a large (percentage) increase in DNS traffic doesn't affect your overall traffic volume, though it might hurt your nameservers. If you're a root server, doubling the DNS traffic nearly doubles total traffic volume, so in addition to DNS-specific issues, you'll also start looking at full pipes. -Dave -- work: [email protected] me: [email protected] MIT Laboratory for Computer Science http://www.angio.net/
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