Re: two-week review: registering formal "rdns" NID (Dale R. Worley) Fri, 19 February 2016 20:41 UTC

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From: (Dale R. Worley)
To: "Ing-Wher \(Helen\) Chen" <>
Subject: Re: two-week review: registering formal "rdns" NID
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Comments on draft-chen-rdns-urn-02:

"Ing-Wher (Helen) Chen" <> writes:
>> Comments on draft-chen-rdns-urn-00:
> [Helen]  Just a note that at the time that I submitted to
>       for review, the latest version was -01.

I should have noticed that!

I think your changes take care of the problems that I've noticed.

>> The rule for lexical equivalence can't be implemented because there is no
>> algorithm for parsing an "rdns" URN into <reverse-dns> and <dss>, and the
>> lexical equivalence rule specifies that <reverse-dns> is case-insensitive and
>> <dss> is case-sensitive (as far as I can tell; you should update the wording).
> [Helen]  I updated the section on "Rules for Lexical Equivalence".  On second
>                thought, because "rdns" URNs are meant to be XML
>                namespaces of enterprise YANG modules, I think the
>                rules for lexical equivalence for "rdns" URNs should be
>                as defined for those of XML namespaces.

There might be a problem, as RFC 2141 prescribes that "urn" and the NID
("rdns") are case-insensitive, whereas the draft prescribes that all of
the URN is to be compared case-sensitively.  Looking at RFC 3406, the
definition of the NID registration template, Appendix B.1 gives an

   Rules for Lexical Equivalence:

      FQDNs are case-insensitive.  Thus, the portion of the URN

                  urn:<assigned number>:<FQDN>:

      is case-insensitive for matches.  The remainder of the identifier
      must be considered case-sensitive.

The syntax for rdns URNs is

       "rdns" URN    ::= urn:rdns:<reverse-dns>:<dss>
       <reverse-dns> ::= registered domain name in reverse, each label
                         separated by a colon (":")
       <dss>         ::= 1*<URN chars>

I think we are constrained to require (for URN comparison) that "urn"
and "rdns" be case-insensitive, whereas you can specify whatever rule
you want for the reverse-dns and dss parts.

But perhaps other people on this list have more knowledge of how this
issue has been handled for other URN namespaces.