Robert Elz <[EMAIL PROTECTED]> writes: > As I recall, the only argument I've ever heard, is that the 'u' bit is > important, because sometime in the future someone might come up with some > scheme that will allow these "globally unique" IIDs to be treated specially > for some purpose or other. And even though that's just wild speculation, > I could almost buy that (I'm one of the people who doesn't mind making > allowances for things that might happen in the future in general, even if > we don't know what they are) - except that no-one has been able to tell me > how we would ever cope with devices that simply have no idea if their > MAC address is globally unique or not (and so really, in this interpretation > would have to always leave the 'u' bit clear in all addresses - I can > easily show that KAME would be broken according to this interpretation for > example - that is, I can have it autoconfigure addresses with the 'u' bit > set where the IID isn't globally unique - and I certainly can't imagine > a way the KAME people could fix it, other than by never setting 'u'), and > perhaps more importantly, as that one can always be hand waved away as a > "configuration error" (though the imaginary protocol using this would have > to deal with it, somehow) how we deal with address stability when a MAC > address changes, so the IPv6 address is no longer based upon an EUI-64, > though it used to be.
You seem to be wanting to require that if the u-bit is set, it is *guaranteed* to be globally unique. No one can make such a guarantee, of course. I have always viewed the u bit a way of indicating that the IID is probably unique, with a high degree of likelyhood. This is achieved by setting the u bit to 1, iff the ID is derived from an IEEE identifier. > So, let me turn the question around. Is there anyone out there who believes > the draft should stay as it is (in this area) and who is willing to attempt > to explain why? I've tried to do so in another note. > If there's no-one, then to me that looks like consensus for a change... Not so fast. To change the status quo, one needs more than just a couple of people saying "yes" and the vast majority of the community being silent. Thomas -------------------------------------------------------------------- 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] --------------------------------------------------------------------
