2012-12-20 19:34, "Fred Baker (fred)" <f...@cisco.com> : > > On Dec 20, 2012, at 9:35 AM, Rémi Després wrote: >>> The comment Brian is making refers to IP's requirements, which are that the >>> IID used in a subnet by an interface must be unique within that subnet. >> >> This is a clear requirement, on which I think we all agree. >> >> It is worth noting here that satisfaction of this requirement DOES DEPEND in >> part on IIDs having u=1 being actually unique. >> (Reason is that RFC 4862 says (uppercase added) "IPv6 nodes are NOT required >> to validate that interface identifiers created with modified EUI-64 tokens >> with the "u" bit set to universal are unique".) > > Which, operationally, has been proven to be faulty. Some networks, notably > virtual machines but also physical NICs that have resulted from manufacturing > errors, theoretically have unique addresses but in practical fact don't.
Where two NICs on the same link have the same universal-scope EUI-64 address (which can as you say result from manufacturing errors), problems will exist, right. (Actually, these problems start at the link layer, independently from whether DAD is active for them at the IP layer.) I don't see a difference of understanding on this. Regards, RD -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
