On Wed, Apr 21, 2010 at 9:35 PM, <Valdis.Kletnieks@vt.edu> wrote:
On Thu, 22 Apr 2010 07:30:51 +0930, Mark Smith said:
" The following table shows the probability of a collision for a range of connections using a 40-bit Global ID field.
Connections Probability of Collision
2 1.81*10^-12 10 4.54*10^-11 100 4.54*10^-09 1000 4.54*10^-07 10000 4.54*10^-05
Based on this analysis, the uniqueness of locally generated Global IDs is adequate for sites planning a small to moderate amount of inter-site communication using locally generated Global IDs."
There is a measured rate by RIRs and the like on the order of 10^-6 for accidentally issuing duplicate integers (roughly approximated by 2 cases of duplicate ASNs out of (300K routes + 30K ASNs). In other words, unless you have over 1,000 or so backdoor links, you're more likely to get screwed over by an administrative drone fscking up your paperwork than you are of a statistical collision.
it's not about the frequency of collision, it's about the cost to rectify one/two/some. and the complexity this adds to every host/router/device in/around the network (dns, firewalls, acls, etc... icky) -chris