Re: RFC 2141 on URN Syntax

Hi,
  I wanted to mention some things about the rfc 2141 that I found confusing.
I feel that the details should be verified.

The syntax for a URN is specified as
<URN> ::= "urn:" <NID> ":" <NSS>
and NSS also has ":" as a characters recognized within the <others> rule.
Based on this
    URN:foo::      -> Is this a valid URN ??

I feel that is ":" is used as a reserved terminator of a subsection of a
rule then it should not be used in the recognized character sets for the
other sub-sections of the rule. So I would imagine that ":" is not present
as a recognizable character within the <other> rule of NSS subsection.

It just adds an extra amount of parsing effort for the applications to have
this feature in their parsing mechanisms. I don't say that it is impossible
to have it, but as a application developer, it  would be a much messy
approach for me to write code that has this feature in it. I hope this not
taken as a negative criticism. 

I have a similar concern regarding the usage of "%" character within the
<NSS> subsection. This is what the rule resolution says 
<NSS> ::= 1*<URN chars>
<URN chars> ::= <trans> | "%" <hex> <hex>
<trans> ::= <upper> | <lower> | <number> | <other> | <reserved>
<reserved> ::= '%" | "/" | "?" | "#"

Here we observe that 

  <NSS> ::= %    could be a valid rule according to the  rule definition. At
the same time the system has another defination that says wheneever "%" is
used two  <hex> characters should be used.

  <NSS> ::=%%12  -> could also be a valid syntax for NSS.  

My suggestion here is to remove "%" from the <reserved> subsection of <NSS>
rules.

Please let me know if my thinking is along the lines of what the group has
in mind or am I way out of wack. I appreciate your acceptance of my
participation in the group.

Thank You
Sukanta Ganguly

>>> Jim Whitehead <ejw@ics.uci.edu> 05/06/97 12:07PM >>>

Of potential interest to participants of this WG.

- Jim

>To: IETF-Announce: ;
>Subject: RFC 2141 on URN Syntax
>Cc: rfc-ed@isi.edu 
>Mime-Version: 1.0
>Date: Mon, 05 May 97 13:53:28 PDT
>Sender:ietf-announce-request@ietf.org 
>From: RFC Editor <rfc-ed@isi.edu>
>
>
>A new Request for Comments is now available in online RFC libraries.
>
>
>        RFC 2141:
>
>        Title:      URN Syntax
>        Author:     R. Moats
>        Date:       May 1997
>        Mailbox:    jayhawk@ds.internic.net 
>        Pages:      8
>        Characters: 14077
>        Updates/Obsoletes: None
>
>        URL:        ftp://ds.internic.net/rfc/rfc2141.txt 
>
>
>Uniform Resource Names (URNs) are intended to serve as persistent,
>location-independent, resource identifiers. This document sets
>forward the canonical syntax for URNs.  A discussion of both existing
>legacy and new namespaces and requirements for URN presentation and
>transmission are presented.  Finally, there is a discussion of URN
>equivalence and how to determine it. This document is the product of
>the Uniform Resource Names Working Group of the IETF.
>
>This is now a Proposed Standard Protocol.
>
>This document specifies an Internet standards track protocol for the
>Internet community, and requests discussion and suggestions for
>improvements.  Please refer to the current edition of the "Internet
>Official Protocol Standards" (STD 1) for the standardization state and
>status of this protocol.  Distribution of this memo is unlimited.
>
>This announcement is sent to the IETF list and the RFC-DIST list.
>Requests to be added to or deleted from the IETF distribution list
>should be sent to IETF-REQUEST@CNRI.RESTON.VA.US.  Requests to be
>added to or deleted from the RFC-DIST distribution list should
>be sent to RFC-DIST-REQUEST@ISI.EDU.
>
>Details on obtaining RFCs via FTP or EMAIL may be obtained by sending
>an EMAIL message to rfc-info@ISI.EDU with the message body
>help: ways_to_get_rfcs.  For example:
>
>        To: rfc-info@ISI.EDU 
>        Subject: getting rfcs
>
>        help: ways_to_get_rfcs
>
>Requests for special distribution should be addressed to either the
>author of the RFC in question, or to admin@DS.INTERNIC.NET.  Unless
>specifically noted otherwise on the RFC itself, all RFCs are for
>unlimited distribution.
>
>Submissions for Requests for Comments should be sent to
>RFC-EDITOR@ISI.EDU.  Please consult RFC 1543, Instructions to RFC
>Authors, for further information.
>
>
>Joyce K. Reynolds and Mary Kennedy
>USC/Information Sciences Institute
>

Received on Friday, 9 May 1997 10:57:03 UTC