On Sun, 25 Jul 2010 11:40:19 +0300, Saku Ytti said:
On (2010-07-25 17:32 +1000), Karl Auer wrote:
The risk of a ULA prefix conflict is for *all practical purposes* zero.
http://www.wolframalpha.com/input/?i=1-((2^40)!)%2F((2^40)^1000000+((2^40)-1000000)!)+
It wouldn't puke nice graph with 'n', it did try, but never finished.
So if there are million assigned ULA's there is 36.5% chance of collision, if formula is right.
Bzzt! Wrong, but thank you for playing. If there exists some screwed-up network design that *interconnects* 1M networks that are all *advertising* ULAs there's a 36% chance of collision. It's a subtle but important difference. You only care about a collision if (a) you and some site in Zimbabwe both chose the same ULA prefix *AND* (b) you wish to set up a private interconnect with them and talk with them *using the ULA prefix*. Very important 'and' there. On the other hand, today if you interconnect *3* private networks that use NAT you have like a 90% chance of collision. And yet, people manage to do this all the time. So ULAs give a way to make it literally a million times easier - and THOSE SAME PEOPLE WHO DO THIS WITH NAT ADDRESSES ALL THE TIME ARE WHINING ULA IS UNWORKABLE. Geez guys, give me a break.