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Versions: 00 01 02 03 04 05 06 07 08 09 10 RFC 3405

Network Working Group                                        M. Mealling
Internet-Draft                                   Network Solutions, Inc.
Category: Informational                                    February 1999
Expires: August 02, 1999


           Assignment Procedures for URI Resolution using DNS
                  draft-ietf-urn-net-procedures-02.txt

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that
   other groups may also distribute working documents as
   Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other documents
   at any time. It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   To view the entire list of Internet-Draft Shadow Directories, see
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on August 02, 1999.

Abstract

   RFC2168 defines a DNS resource record and an algorithm for using DNS
   as a registry for retrieving URI delegation rules (sometimes called
   resolution hints). That document specifies that the first step in
   that algorithm is to append 'uri.net' to the URI scheme and retrieve
   the NAPTR record for that domain-name.  I.e., the first step in
   resolving "http://foo.com/" would be to look up a NAPTR record for
   the domain "http.uri.net". URN resolution also follows a similar
   procedure but uses the 'urn.net' zone as its root. This document
   describes the procedures for inserting a new rule into the 'uri.net'
   and 'urn.net' zones.

Copyright Notice

   Copyright (C) The Internet Society (1999). All Rights Reserved.







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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  URI Resolution vs URN Resolution . . . . . . . . . . . . . . .  3
   3.  URI Registration Procedure . . . . . . . . . . . . . . . . . .  3
   4.  URN Registration Procedure . . . . . . . . . . . . . . . . . .  3
   5.  Requirements on rules  . . . . . . . . . . . . . . . . . . . .  3
   6.  Submission Procedure . . . . . . . . . . . . . . . . . . . . .  4
   7.  Registration Template  . . . . . . . . . . . . . . . . . . . .  5
   7.1 Key  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   7.2 Authority  . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   7.3 Records  . . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   8.  Example Template . . . . . . . . . . . . . . . . . . . . . . .  5
   9.  The URN Registration in the uri.net zone . . . . . . . . . . .  5
   10. IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  6
       References . . . . . . . . . . . . . . . . . . . . . . . . . .  6
       Author's Address . . . . . . . . . . . . . . . . . . . . . . .  7


































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1. Introduction

   This document defines the policies and procedures for inserting
   NAPTR records into the 'uri.net' and 'urn.net' zones for the purpose
   of resolving URIs according to "Resolution of Uniform Resource
   Identifiers using the Domain Name System", RFCXXXX[1], which is an
   application of the NAPTR DNS Resource Record defined in RFCXXXX[2].

2. URI Resolution vs URN Resolution

   RFCXXXX[1] defines how both URI resolution and URN[3] resolution
   work. Specifically it says that all URIs rules are registered in
   'uri.net'. Since a URN is a URI it follows the same rules. Thus one
   of the rules in the 'uri.net' zone is the one for a URN. This rule
   states that the namespace id [4] is extracted, 'urn.net' is appended
   to the end of the namespace id, and the next NAPTR  record[2] is
   retrieved.

3. URI Registration Procedure

   At this time there is no set procedure for registering new URI
   schemes other than a published RFC. Due to this lack and the
   existence of non-published schemes such as "about" and "res", there
   is an IETF working group discussing how to deal with this problem.
   Thus, at this time the only requirements for requesting an entry in
   the uri.net zone is that the URI scheme be published or in use
   somewhere and that it not conflict with an existing URI scheme.

   When the IETF does standardize a set of procedures for vetting and
   registering new URI schemes, the 'uri.net' registration procedures
   MUST adhere to those procedures for determining if the URI scheme in
   question is valid.

4. URN Registration Procedure

   RFCXXXX[6] defines the procedures for assignment of new URN
   namespace-ids.  Since the 'urn.net' registration procedures only
   deal with the namespace-id portion of the URN space, that document
   is the sole determining document for what can be entered into the
   urn.net zone for a URN.

5. Requirements on rules

   Delegation of a namespace can happen in two ways. In the case of
   most URIs where the entity being delegated to is hard-coded into the
   identifier itself, the syntax of where this is located is set. In
   the case where the entity being delegated to is set in the rule,
   that entity can change as the rule changes.



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   One of the optimizations that the both the URI and URN registries
   attempts to make is that any entry in that zone should have an
   extremely long time to live. 'Extremely long' should be measured in
   years if possible.  Thus, any rule that can change must be delegated
   out of the urn.net zone by a replacement rule in the NAPTR record.
   For example, the 'foo' URN namespace has flexible rules for how
   delegation takes place. Instead of putting those rules in the
   urn.net zone, the entry instead punts those rules off to a
   nameserver that has a shorter time to live. The record in urn.net
   would look like this:


       foo     IN NAPTR 100 10  ""  "" "" urn-resolver.foo.com.


   Thus, when the client starts out in the resolution process, the
   second step is to begin asking 'urn-resolver.foo.com' for the NAPTR
   records that contain the resolution rules. The TTL at the root is
   very long. The TTL at the 'urn-resolver.foo.com' is much shorter.

   Conversely, the 'http' URL scheme adheres to a particular syntax
   that specifies that the host to ask is specified in the URL in
   question. Since this syntax does not change, that rule can be
   specified in the uri.net zone. The record would look like this:

       http    IN NAPTR 100 100 "" ""  "/http:\\/\\/([^\\/:]+)/\\2/i" .

   Thus, the second step of resolution is to attempt to contact the
   host contained in the URL itself.

6. Submission Procedure

   Using the MIME Content-Type registration mechanism[5]as a model for
   a successful registration mechanism, the 'uri.net' and 'urn.net'
   procedures consist of a request template submitted to an open
   mailing list made up of interested parties. If no objections are
   made within a two week period, a representative of the registration
   authority considers the submission to be accepted and enters that
   submission into the nameserver.

   o  Registrations for the 'uri.net' zone are sent to
      'register@uri.net'.
   o  Registrations for the 'urn.net' zone are sent to
      'register@urn.net'.

   At this time the registration authority is expected to be the IANA.

   Objections are restricted to those that point out impacts on the
   zone itself or to DNS in general. Objections to the URL scheme or to


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   the URN namespace-id are not allowed, as these should be raised in
   their respective forums. The logical conclusion of this is that ANY
   sanctioned URL scheme or URN namespace MUST be allowed to be
   registered if it meets the requirements specified in this document
   as regards times to live and general impact to the DNS.

7. Registration Template

   The template to be sent to the appropriate list MUST contain the
   following values:

7.1 Key

   This is the URN NID or URL scheme, which is used as the domain
   portion of the DNS entry. It must be valid according to the
   procedures specified in the URN namespace-id assignment document and
   any future standards for registering new URL schemes.

7.2 Authority

   This is the authority doing the registration of the record. It must
   be an authority recognized as either the IESG or any authority
   defined in the URN NID[6] or URL scheme registration[7] documents.

7.3 Records

   The actual DNS records representing the rule set for the key. The
   required values are Preference, Order, Flags, Services, Regex, and
   Replacement as defined by RFCXXXX[2].

8. Example Template

   To: register@urn.net
   From: joe@foo.com

   Key: foo
   Authority: Foo Technology, Inc as specified in RFCFOO
   Record: foo  IN NAPTR 100 100 "" "" "" urn.foo.com.


9. The URN Registration in the uri.net zone

   Since this document discusses the uri.net and urn.net zones and the
   URN rule that exists in the uri.net zone, it makes sense for the
   regisration template for the URN URI rule to be specified here:






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   To: register@uri.net
   From: The IETF URN Working Group

   Key: urn
   Authority: RFC2141
   Record: urn  IN NAPTR 0 0 "" "" "/urn:([^:]+)/\\2/i" .

10. IANA Considerations

   This document describes a mechanism for registering representations
   of protocol items that have already been registered with some IETF
   sanctioned agency (probably the IANA as well). This means that the
   IANA need not determine appropriateness of the underlying
   namespaces, since that is determined by another process.

   The only real impact on the IANA will be

   o  to maintain (or designate some other entity to maintain) a
      primary nameserver for the uri.net and urn.net zones;
   o  to maintain the mailing lists "register@uri.net" and
      "register@uri.net" as the forum for discussions of submissions;
      and
   o  to act as the party that determines if all objections have been
      noted and accommodated.

References

   [1]  Mealling, M., Daniel, R., "Resolution of Uniform Resource
        Identifiers using the Domain  Name System", November 1998.

   [2]  Mealling, M., Daniel, R., "The Naming Authority Pointer (NAPTR)
        DNS Resource Record", November 1998.

   [3]  Moats, R., "URN Syntax", RFC 2141, May 1997.

   [4]  Berners-Lee, T., Fielding, R., Masinter, L., "Uniform Resource
        Identifiers (URI): Generic Syntax", RFC 2396, August 1998.

   [5]  Freed, N., Klensin, J., Postel, J., "Multipurpose Internet Mail
        Extensions (MIME) Part Four: Registration Procedures", RFC
        2048, November 1996.

   [6]  Faltstrom, P., Iannella, R., Daigle, L., van Gulik, D., "URN
        Namespace Definition Mechanisms", October 1998.

   [7]  Petke, R., King, I., "Registration Procedures for URL Scheme
        Names", January 1999.




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Author's Address

   Michael Mealling
   Network Solutions, Inc.
   505 Huntmar Park Drive
   Herndon, VA  22070
   US

   Phone: +1 770 935 5492
   EMail: michaelm@netsol.com
   URI:   http://www.netsol.com








































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Full Copyright Statement

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implmentation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph
   are included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
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   The limited permissions granted above are perpetual and will not be
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   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
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   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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