RD> Date: Wed, 7 Jan 2009 08:50:46 +0800 RD> From: Roland Dobbins RD> > I've seen _many_ routing problems appear in large WANs that simply RD> > can't be replicated with fewer than a hundred or even a thousand RD> > routers. RD> Users can simulate many of these conditions themselves using various many != all It appears to be a question of what incremental benefit does one gain from real-world testing? RD> open-source and commercial tools, which've been available for many RD> years. I think that everyone agrees: No live testing until "adequate" lab testing has been performed. The disagreement seems to be over when/if live testing is necessary, and how much. Because it just wouldn't be a NANOG thread without analogies *grin*, I offer the following: drug certification, aircraft certification, automobile crash testing, database benchmarking. Even when a system is highly deterministic, such as a database, one still expects _real-world_ testing. Traffic flows on large networks are highly stochastic... and this includes OPNs, which I posit are futile to attempt to model. RD> And again, it comes back to understanding the performance envelope RD> of one's equipment, even without simulation. Very true. If one deploys an OSPF-happy network thinking that it scales O(n), one is in for a rude shock. Eddy -- Everquick Internet - http://www.everquick.net/ A division of Brotsman & Dreger, Inc. - http://www.brotsman.com/ Bandwidth, consulting, e-commerce, hosting, and network building Phone: +1 785 865 5885 Lawrence and [inter]national Phone: +1 316 794 8922 Wichita ________________________________________________________________________ DO NOT send mail to the following addresses: davidc@brics.com -*- jfconmaapaq@intc.net -*- sam@everquick.net Sending mail to spambait addresses is a great way to get blocked. Ditto for broken OOO autoresponders and foolish AV software backscatter.