Re: [urn] Working Group Last Call of draft-ietf-urnbis-rfc2141bis-urn-06.txt

[Keith Moore <[e-mail]>]

Section 4.3 needs work.   The text in -06 is worse than the text in 2141.

It is a Very Bad Idea to allow queries and fragments in URNs and not 
define what they mean.  This will lead to conflicts in interpretation of 
queries and/or fragments between different resolution services and/or 
different namespaces (and perhaps also different user interfaces) which 
will then result in inconsistent handling of URNs containing queries 
and/or fragments.

The only interpretation of queries and fragments that is at all 
consistent with RFC 3986, and still makes sense for URNs, is for queries 
and fragments to be evaluated entirely in the context of the referenced 
resource.   They must not be interpreted by URN resolution services, and 
the query and fragment parts of a URN need to be stripped before feeding 
a URN to a resolution service.

Furthermore, more text is needed to explain that even though a URN 
without a query or fragment is a persistent name (has a persistent 
binding to whatever it was originally associated with), there is no 
assurance of persistence for a URN that has a query or fragment portion.

Keith

> 4.3.  Query Component and Fragment Identifier Component
>
>     The URI specification [RFC3986] allows a query component, a fragment
>     identifier component, or both after the path component of a URI,
>     where the character '?' is used as a separator to denote the
>     beginning of the query component and the character '#' is used as a
>     separator to denote the beginning of the fragment identifier
>     component.  The original URN syntax specification [RFC2141] reserved
>     the '?' and '#' characters for future developments.  This
>     specification aligns URN syntax with URI syntax by allowing the query
>     component and fragment identifier component after (not within) the
>     Namespace Specific String (NSS).
>
>     This specification does not define the applicability and semantics of
>     the query component or the fragment identifier component in URNs.
>     Additional specifications might establish these matters for URN-
>     related services (such as resolution) or for individual URN
>     namespaces.  For example, it is possible that the query component
>     might be used in requests to URN resolution services, or that the
>     fragment identifier component might be used to distinguish the
>     integral parts of resources named by URNs.  However, defining such
>     usage is left to specifications for URN resolution services,
>     namespace registration requests and specifications for individual
>     namespaces (which might use some namespace-specific syntax instead of
>     the URI fragment identifier component), and other appropriate
>     documentation (such as policy documents governing the management of a
>     given URN namespace).
>
>     Although URN assignment is often a managed process (see
>     [I-D.ietf-urnbis-rfc3406bis-urn-ns-reg]), the query component or
>     fragment identifier component can be appended after the NSS once a
>     URN has been assigned in accordance with the rules for a given
>     namespace.
>