On Thu, Aug 12, 2004 at 01:35:36PM +0200, Niels Bakker scribed:
* dga@lcs.mit.edu (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: dga@lcs.mit.edu me: dga@pobox.com MIT Laboratory for Computer Science http://www.angio.net/