





Network Working Group                                   D. McWalter, Ed.
Request for Comments: 5017                           Data Connection Ltd
Category: Standards Track                                 September 2007


    MIB Textual Conventions for Uniform Resource Identifiers (URIs)

Status of This Memo

   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.

Abstract

   This MIB module defines textual conventions to represent STD 66
   Uniform Resource Identifiers (URIs).  The intent is that these
   textual conventions will be imported and used in MIB modules that
   would otherwise define their own representation(s).

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 1
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 2
   3.  The Internet-Standard Management Framework  . . . . . . . . . . 2
   4.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . 2
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 5
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     8.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     8.2.  Informative References  . . . . . . . . . . . . . . . . . . 6

1.  Introduction

   This memo defines a portion of the Management Information Base (MIB)
   for use with network management protocols in the Internet community.
   It defines textual conventions to represent STD 66 [RFC3986] URIs,
   which are further described by [RFC3305].

   Three textual conventions are defined: one of unrestricted length,
   and two of different restricted lengths.  Which length is appropriate
   will depend on tradeoffs made in particular MIB modules.  The purpose
   of providing standard restricted-length textual conventions is to
   improve compatibility between MIB modules that require restricted-
   length URIs.



McWalter                    Standards Track                     [Page 1]

RFC 5017                       URI TC MIB                 September 2007


   If a URI needs to be used as an index object, then the 'Uri' TEXTUAL-
   CONVENTION SHOULD be subtyped to a length appropriate for the Object
   Identifier (OID) of which it is part.  The description of the 'Uri'
   TEXTUAL-CONVENTION discusses this case.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

3.  The Internet-Standard Management Framework

   For a detailed overview of the documents that describe the current
   Internet-Standard Management Framework, please refer to section 7 of
   RFC 3410 [RFC3410].

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  MIB objects are generally
   accessed through the Simple Network Management Protocol (SNMP).
   Objects in the MIB are defined using the mechanisms defined in the
   Structure of Management Information (SMI).  This memo specifies a MIB
   module that is compliant to the SMIv2, which is described in STD 58,
   RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
   [RFC2580].

4.  Definitions

URI-TC-MIB DEFINITIONS ::= BEGIN

IMPORTS
    MODULE-IDENTITY, mib-2             FROM SNMPv2-SMI      -- [RFC2578]
    TEXTUAL-CONVENTION                 FROM SNMPv2-TC;      -- [RFC2579]

uriTcMIB MODULE-IDENTITY
    LAST-UPDATED "200709100000Z" -- 10 September 2007
    ORGANIZATION "IETF Operations and Management (OPS) Area"
    CONTACT-INFO "EMail: ops-area@ietf.org
                  Home page: http://www.ops.ietf.org/"
    DESCRIPTION
            "This MIB module defines textual conventions for
            representing URIs, as defined by RFC 3986 STD 66."
    REVISION     "200709100000Z" -- 10 September 2007
    DESCRIPTION
           "Initial revision, published as RFC 5017.

            Copyright (C) The IETF Trust (2007).  This version of this
            MIB module is part of RFC 5017; see the RFC itself for full



McWalter                    Standards Track                     [Page 2]

RFC 5017                       URI TC MIB                 September 2007


            legal notices."
    ::= { mib-2 164 }

Uri ::= TEXTUAL-CONVENTION
   DISPLAY-HINT "1a"
   STATUS      current
   DESCRIPTION
            "A Uniform Resource Identifier (URI) as defined by STD 66.

            Objects using this TEXTUAL-CONVENTION MUST be in US-ASCII
            encoding, and MUST be normalized as described by RFC 3986
            Sections 6.2.1, 6.2.2.1, and 6.2.2.2.  All unnecessary
            percent-encoding is removed, and all case-insensitive
            characters are set to lowercase except for hexadecimal
            digits, which are normalized to uppercase as described in
            Section 6.2.2.1.

            The purpose of this normalization is to help provide unique
            URIs.  Note that this normalization is not sufficient to
            provide uniqueness.  Two URIs that are textually distinct
            after this normalization may still be equivalent.

            Objects using this TEXTUAL-CONVENTION MAY restrict the
            schemes that they permit.  For example, 'data:' and 'urn:'
            schemes might not be appropriate.

            A zero-length URI is not a valid URI.  This can be used to
            express 'URI absent' where required, for example when used
            as an index field.

            Where this TEXTUAL-CONVENTION is used for an index field,
            it MUST be subtyped to restrict its length.  There is an
            absolute limit of 128 subids for an OID, and it is not
            efficient to have OIDs whose length approaches this
            limit."
   REFERENCE "RFC 3986 STD 66 and RFC 3305"
   SYNTAX      OCTET STRING

Uri255 ::= TEXTUAL-CONVENTION
   DISPLAY-HINT "255a"
   STATUS      current
   DESCRIPTION
            "A Uniform Resource Identifier (URI) as defined by STD 66.

            Objects using this TEXTUAL-CONVENTION MUST be in US-ASCII
            encoding, and MUST be normalized as described by RFC 3986
            Sections 6.2.1, 6.2.2.1, and 6.2.2.2.  All unnecessary
            percent-encoding is removed, and all case-insensitive



McWalter                    Standards Track                     [Page 3]

RFC 5017                       URI TC MIB                 September 2007


            characters are set to lowercase except for hexadecimal
            digits, which are normalized to uppercase as described in
            Section 6.2.2.1.

            The purpose of this normalization is to help provide unique
            URIs.  Note that this normalization is not sufficient to
            provide uniqueness.  Two URIs that are textually distinct
            after this normalization may still be equivalent.

            Objects using this TEXTUAL-CONVENTION MAY restrict the
            schemes that they permit.  For example, 'data:' and 'urn:'
            schemes might not be appropriate.

            A zero-length URI is not a valid URI.  This can be used to
            express 'URI absent' where required, for example when used
            as an index field.

            STD 66 URIs are of unlimited length.  Objects using this
            TEXTUAL-CONVENTION impose a length limit on the URIs that
            they can represent.  Where no length restriction is
            required, objects SHOULD use the 'Uri' TEXTUAL-CONVENTION
            instead.  Objects used as indices SHOULD subtype the 'Uri'
            TEXTUAL-CONVENTION."
   REFERENCE "RFC 3986 STD 66 and RFC 3305"
   SYNTAX      OCTET STRING (SIZE (0..255))

Uri1024 ::= TEXTUAL-CONVENTION
   DISPLAY-HINT "1024a"
   STATUS      current
   DESCRIPTION
            "A Uniform Resource Identifier (URI) as defined by STD 66.

            Objects using this TEXTUAL-CONVENTION MUST be in US-ASCII
            encoding, and MUST be normalized as described by RFC 3986
            Sections 6.2.1, 6.2.2.1, and 6.2.2.2.  All unnecessary
            percent-encoding is removed, and all case-insensitive
            characters are set to lowercase except for hexadecimal
            digits, which are normalized to uppercase as described in
            Section 6.2.2.1.

            The purpose of this normalization is to help provide unique
            URIs.  Note that this normalization is not sufficient to
            provide uniqueness.  Two URIs that are textually distinct
            after this normalization may still be equivalent.

            Objects using this TEXTUAL-CONVENTION MAY restrict the
            schemes that they permit.  For example, 'data:' and 'urn:'
            schemes might not be appropriate.



McWalter                    Standards Track                     [Page 4]

RFC 5017                       URI TC MIB                 September 2007


            A zero-length URI is not a valid URI.  This can be used to
            express 'URI absent' where required, for example when used
            as an index field.

            STD 66 URIs are of unlimited length.  Objects using this
            TEXTUAL-CONVENTION impose a length limit on the URIs that
            they can represent.  Where no length restriction is
            required, objects SHOULD use the 'Uri' TEXTUAL-CONVENTION
            instead.  Objects used as indices SHOULD subtype the 'Uri'
            TEXTUAL-CONVENTION."
   REFERENCE "RFC 3986 STD 66 and RFC 3305"
   SYNTAX      OCTET STRING (SIZE (0..1024))

END

5.  Security Considerations

   See also the Security Considerations of STD 66 [RFC3986].

   This MIB module does not define any management objects.  Instead, it
   defines a textual convention that may be imported by other MIB
   modules and used for object definitions.

   Meaningful security considerations can only be written in the MIB
   modules that define management objects.  This document therefore has
   no impact on the security of the Internet.

6.  IANA Considerations

   URI-TC-MIB is rooted under the mib-2 subtree.  IANA has assigned {
   mib-2 164 } to the URI-TC-MIB module specified in this document.

7.  Acknowledgements

   This module was generated by editing together contributions from
   Randy Presuhn, Dan Romascanu, Bill Fenner, Juergen Schoenwaelder, and
   others.

8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2578]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Structure of Management Information
              Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.



McWalter                    Standards Track                     [Page 5]

RFC 5017                       URI TC MIB                 September 2007


   [RFC2579]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Textual Conventions for SMIv2",
              STD 58, RFC 2579, April 1999.

   [RFC2580]  McCloghrie, K., Perkins, D., and J. Schoenwaelder,
              "Conformance Statements for SMIv2", STD 58, RFC 2580,
              April 1999.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, January 2005.

8.2.  Informative References

   [RFC3305]  Mealling, M. and R. Denenberg, "Report from the Joint W3C/
              IETF URI Planning Interest Group: Uniform Resource
              Identifiers (URIs), URLs, and Uniform Resource Names
              (URNs): Clarifications and Recommendations", RFC 3305,
              August 2002.

   [RFC3410]  Case, J., Mundy, R., Partain, D., and B. Stewart,
              "Introduction and Applicability Statements for
              Internet-Standard Management Framework", RFC 3410,
              December 2002.

Author's Address

   David McWalter (editor)
   Data Connection Ltd
   100 Church Street
   Enfield  EN2 6BQ
   United Kingdom

   EMail: dmcw@dataconnection.com

















McWalter                    Standards Track                     [Page 6]

RFC 5017                       URI TC MIB                 September 2007


Full Copyright Statement

   Copyright (C) The IETF Trust (2007).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
   THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
   THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.












McWalter                    Standards Track                     [Page 7]

