On 2011-09-20 11:21, Sander Steffann wrote: > Hi, > >> It would better if it also specified where to use :: if there >> is more than one run of zeros. As in >> >> If an address contains more than one group of zeros where "::" >> could be used, only the {least|most} significant such group >> may be represented by "::". >> >> Take your pick between "least" and "most". >> >> If we don't have such a rule, I fear that the only unambiguous rule for >> prefixes is to avoid abbreviation. > > > I think that RFC 5952 (an update on RFC 4291) provides the guidance you > describe in section 4.2.3.
I see that it does (and the errata on 4291 do not). Thanks. A reasonable prefix will end with at least 64 zeros, so :: will always be the last element according to RFC 5952. (Unless someone uses prefixes longer than /64, in which case I for one don't care.) Brian -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------