As you point out uniqueness is not guaranteed, even for administrative assignments. That is why RFC 2462 specifically states: The Duplicate Address Detection algorithm is performed on all addresses, independent of whether they are obtained via stateless or stateful autoconfiguration.
In a quick scan of 3041 I didn't see a reference to that, but it was a fundemental assumption. If 3041 is updated it would probably help to have a clear pointer back to 2462. Tony > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Alexandru Petrescu > Sent: Tuesday, February 05, 2002 5:14 AM > To: [EMAIL PROTECTED] > Subject: Randomness and uniqueness > > > Hi, there's currently a stream of proposals that put random bits on > the Interface ID of an IPv6 address. A background assumption is that > the length of the Interface ID is 64 bits. Another assumption is that > since those ID's are generated from random sources, then their > uniqueness is guaranteed for practical purposes. > > May I point out the following: > > -mathematical uniqueness is not guaranteed, there's already an > acknowledged collision probability. > -to this probability one should add "administrative probability" where > same prefixes are accidentally assigned to two entities. > -add implementation error probabilities, where a widespread > implementation uses a weak algorithm to generate that random numbers, > for example use as input time of day or the birth date, or short > passphrases, etc. > -add the p in prf. > > The last three factors are very hard to quantify, and as such the > overall probability of collision events also seems to me very hard to > quantify. > > Just a thought, born out of contemplating randomness. What do you > think? > > Alex > > > -------------------------------------------------------------------- > IETF IPng Working Group Mailing List > IPng Home Page: http://playground.sun.com/ipng > FTP archive: ftp://playground.sun.com/pub/ipng > Direct all administrative requests to [EMAIL PROTECTED] > -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
