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Versions: 00 01 draft-ietf-6man-uri-zoneid

6MAN                                                        B. Carpenter
Internet-Draft                                         Univ. of Auckland
Updates: 3986, 4007 (if approved)                              R. Hinden
Intended status: Standards Track                             Check Point
Expires: June 9, 2012                                   December 7, 2011


   Representing IPv6 Zone Identifiers in Uniform Resource Identifiers
                   draft-carpenter-6man-uri-zoneid-00

Abstract

   This document describes how the Zone Identifier of an IPv6 scoped
   address can be represented in a Uniform Resource Identifier that
   includes a literal IPv6 address.  It updates RFC 3986 and RFC 4007.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on June 9, 2012.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   publication of this document.  Please review these documents
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   described in the Simplified BSD License.




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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Specification . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 5
   6.  Change log [RFC Editor: Please remove]  . . . . . . . . . . . . 5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 6







































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1.  Introduction

   [RFC3986] defined how a literal IPv6 address can be represented in
   the "host" part of a Uniform Resource Identifier (URI).
   Subsequently, [RFC4007] extended the text representation of limited-
   scope IPv6 addresses such that a zone identifier may be concatenated
   to an address, for purposes described in that RFC.  Zone identifiers
   are especially useful in contexts where literal addresses are
   typically used, for example during fault diagnosis, when it may be
   essential to specify which interface is used for sending to a link
   local address.  It should be noted that zone identifiers have purely
   local meaning within the host where they are defined, and they are
   completely meaningless for any other host.

   RFC 4007 does not specify how zone identifiers are to be represented
   in URIs.  Practical experience has shown that this feature is useful,
   in particular when using a web browser for debugging with link local
   addresses, but as it is undefined, it is not implemented consistently
   in URI parsers or in browsers.

   This document updates [RFC3986] by adding syntax to allow a zone
   identifier to be included in a literal IPv6 address.  It also
   clarifies some statements in [RFC4007].

   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 [RFC2119].


2.  Specification

   According to RFC 4007, a zone identifier is attached to the textual
   representation of an IPv6 address by concatenating "%" followed by
   <zone_id>, where <zone_id> is a string identifying the zone of the
   address.  However, RFC 4007 gives no precise definition of the
   character set allowed in <zone_id>.  There are no rules or de facto
   standards for this.  For example, the first Ethernet interface in a
   host might be called %0, %1, %en1, %eth0, or whatever the implementer
   happened to choose.

   In a URI, a literal IPv6 address is always embedded between "[" and
   "]".  This document specifies that <zone_id> may contain any ASCII
   character classified in RFC 3986 as "unreserved", which conveniently
   excludes "]" in order to simplify parsing.

   There is an additional complication in that "%" is always treated as
   an escape character in a URI, and according to RFC 3986 it must
   therefore itself be escaped in a URI, in the form "%25".  Thus, the



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   scoped address fe80::a%en1 would appear in a produced URI as
   http://[fe80::a%25en1].

   In RFC 3986, the IPv6 literal format is formally defined in ABNF
   [RFC5234] by the following rule:

      IP-literal = "[" ( IPv6address / IPvFuture  ) "]"

   To provide support for a zone identifier, firstly a new rule is
   added:

       ZoneID = 1*15unreserved

   Then two options are possible (to be discussed).

   OPTION 1:

   The existing syntax of IPv6address is extended by adding a specific
   option for the case of link-local addresses.  The following
   definition of IPv6address replaces that given in RFC 3986:

      IPv6address =  6( h16 ":" ) ls32
                   / "::" 5( h16 ":" ) ls32
                   / [               h16 ] "::" 4( h16 ":" ) ls32
                   / [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32
                   / [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32
                   / [ *3( h16 ":" ) h16 ] "::"    h16 ":"   ls32
                   / [ *4( h16 ":" ) h16 ] "::"              ls32
                   / [ *5( h16 ":" ) h16 ] "::"              h16
                   / [ *6( h16 ":" ) h16 ] "::"
                   / "fe80::" [ *3( h16 ":" ) h16 ] "%" ZoneID

   OPTION 2:

   The existing syntax of IPv6address is retained, and a zone identifier
   may be added optionally to any literal address.  This allows
   flexibility for unknown future uses.  The rule quoted above from RFC
   3986 is replaced by two rules:

      IP-literal = "[" ( IPv6addrz / IPvFuture  ) "]"

      IPv6addrz = IPv6address [ "%" ZoneID ]

   The rules in [RFC5952] SHOULD be applied in producing URIs, and the
   user MUST replace "%" by "%25" when manually constructing such a URI.






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3.  Security Considerations

   The security considerations of [RFC3986] and [RFC4007] apply.  In
   particular, this URI format creates a specific pathway by which a
   deceitful zone index might be communicated, as mentioned in the final
   security consideration of RFC 4007.  It is emphasised that the format
   is intended only for debugging purposes, but of course this intention
   does not prevent misuse.

   IF OPTION 2 IS CHOSEN:

   To limit this risk, implementations SHOULD NOT allow use of the
   format except for link local addresses under prefix fe80::/10.


4.  IANA Considerations

   This document requests no action by IANA.


5.  Acknowledgements

   The lack of this format was pointed out by Kerry Lynn.  Valuable
   comments and contributions were made by...

   This document was produced using the xml2rfc tool [RFC2629].


6.  Change log [RFC Editor: Please remove]

   draft-carpenter-v6ops-label-balance-00: original version, 2011-12-07.


7.  References

7.1.  Normative References

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

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

   [RFC4007]  Deering, S., Haberman, B., Jinmei, T., Nordmark, E., and
              B. Zill, "IPv6 Scoped Address Architecture", RFC 4007,
              March 2005.




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   [RFC5234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234, January 2008.

   [RFC5952]  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
              Address Text Representation", RFC 5952, August 2010.

7.2.  Informative References

   [RFC2629]  Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
              June 1999.


Authors' Addresses

   Brian Carpenter
   Department of Computer Science
   University of Auckland
   PB 92019
   Auckland,   1142
   New Zealand

   Email: brian.e.carpenter@gmail.com


   Robert M. Hinden
   Check Point Software Technologies, Inc.
   800 Bridge Parkway
   Redwood City, CA  94065
   US

   Email: bob.hinden@gmail.com




















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