Hello, Fred, 2012-12-19 01:35, Fred Baker (fred) <f...@cisco.com> :
> Why do we care about u and g in the first place? Is there code in an IPv6 > router or host that interprets them? The current situation is AFAIK the following: (a) No RFC implies behaviors that differ depending on whether g=0 or g=1 in received IIDs. (b) On the contrary, in the SLAAC privacy extension of RFC 4941, which has u=0, addresses can be unicast although they have g=1. The IEEE semantic of group addresses must explicitly be ignored in this case. (c) In the Identifier-Locator Network Protocol of RFC 6741 (ILNP), the IEEE semantic of g=0 applies to unicast addresses (section 3). Besides, "ILNP uses IPv6 multicast for ILNPv6", which implies that addresses are not concerned with IID formats (RFC 4291 sec 2.7). Other formats are envisaged but explicitly depend on further work. The u=g=1 remains unused. Regards, RD > > On Dec 18, 2012, at 3:50 PM, Joel M. Halpern wrote: > >> In reading the discussion,a nd trying to think through what I understand to >> be correct, it seems that there is an unforeseen ambiguity in the way the >> current documents about IPv6 IIDs are written. >> >> I think that there are two possible meanings, ad we should decide explicitly >> which one we want. >> >> 1) u=1 means that the IID is derived from an IEEE OUI (of some form). With >> that meaning, u=1, g=1 is clearly some sort of multi-entity identifier. And >> we should say that somewhere. >> >> 2) u=1, g=1 was unforeseen, and we don't know what it means. In that case, >> we ought to figure out how we want that portion of the IID space used, and >> write it down clearly. It seems to me that allowing this space to be used >> for special-semantic IIDs (with suitable care so that the entire ecosystem >> is not affected by them) is a very reasonable path. >> >> It seems unlikely that there is actual practice in the wild with u=1, g=1 >> under either interpretation. We do now have a request to start using it >> (4rd). So we should decide. >> >> Yours, >> Joel >> -------------------------------------------------------------------- >> IETF IPv6 working group mailing list >> ipv6@ietf.org >> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 >> -------------------------------------------------------------------- > > ---------------------------------------------------- > The ignorance of how to use new knowledge stockpiles exponentially. > - Marshall McLuhan > > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > ipv6@ietf.org > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
