Representing IPv6 Zone Identifiers in Address Literals and Uniform Resource Identifiers
RFC 6874

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Internet Engineering Task Force (IETF)                      B. Carpenter
Request for Comments: 6874                             Univ. of Auckland
Updates: 3986                                                S. Cheshire
Category: Standards Track                                     Apple Inc.
ISSN: 2070-1721                                                R. Hinden
                                                             Check Point
                                                           February 2013

                 Representing IPv6 Zone Identifiers in
           Address Literals and Uniform Resource Identifiers

Abstract

   This document describes how the zone identifier of an IPv6 scoped
   address, defined as <zone_id> in the IPv6 Scoped Address Architecture
   (RFC 4007), can be represented in a literal IPv6 address and in a
   Uniform Resource Identifier that includes such a literal address.  It
   updates the URI Generic Syntax specification (RFC 3986) accordingly.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6874.

Copyright Notice

   Copyright (c) 2013 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
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Carpenter, et al.            Standards Track                    [Page 1]
RFC 6874                  IPv6 Zone IDs in URIs            February 2013

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2.  Specification . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Web Browsers  . . . . . . . . . . . . . . . . . . . . . . . . . 5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Appendix A.  Options Considered . . . . . . . . . . . . . . . . . . 8

1.  Introduction

   The Uniform Resource Identifier (URI) syntax specification [RFC3986]
   defined how a literal IPv6 address can be represented in the "host"
   part of a URI.  Two months later, the IPv6 Scoped Address
   Architecture specification [RFC4007] extended the text representation
   of limited-scope IPv6 addresses such that a zone identifier may be
   concatenated to a literal address, for purposes described in that
   specification.  Zone identifiers are especially useful in contexts in
   which 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 node in which
   they are defined, often being the same as IPv6 interface names.  They
   are completely meaningless for any other node.  Today, they are
   meaningful only when attached to addresses with less than global
   scope, but it is possible that other uses might be defined in the
   future.

   The IPv6 Scoped Address Architecture specification [RFC4007] 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 because it is undefined, it is not implemented
   consistently in URI parsers or in browsers.

   Some versions of some browsers directly accept the IPv6 Scoped
   Address syntax [RFC4007] for scoped IPv6 addresses embedded in URIs,
   i.e., they have been coded to interpret a "%" sign following the
   literal address as introducing a zone identifier [RFC4007], instead
   of introducing two hexadecimal characters representing some percent-
   encoded octet [RFC3986].  Clearly, interpreting the "%" sign as
   introducing a zone identifier is very convenient for users, although