INTERNET-DRAFT                      L. Masinter, J. Gettys, B. Carpenter
draft-masinter-url-ipv6-01
Expires six months after publication date              September 1, 1998

                    Using IPv6 Addresses in URLs

Status of this Memo

   This document is an Internet-Draft.  Internet-Drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas,
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Copyright Notice

   Copyright (C) The Internet Society (1997).  All Rights Reserved.

Abstract

   The normal textual representation for IPv6 addresses as a set
   of colon-separated hexadecimal numbers does not work well with
   most deployed URL-parsing software. This document describes an
   alternate format which will pass unharmed through most URL-parsing
   software.

1. Introduction

   The normal textual representation for IPv6 addresses as a set of
   colon-separated hexadecimal numbers does not work well with most
   deployed URL-parsing software. This document describes an alternate
   format which will pass unharmed through most URL-parsing software.

2. Background

   The standard representation for IPv6 addresses in text is defined
   in section 2.2 of [RFC2373] ("Text Representation of Addresses").
   This representation uses hexadecimal values separated by colon ":",
   double colon "::", and optionally ending period-separated decimal
   values for the four low-order 8-bit pieces of the address.

   Unfortunately, using this IPv6 syntax within URLs [RFC2396] would
   be disruptive for many applications. Within the "hostport" section
   of the generic URI syntax, the colon is used to separate the host
   name or address from an (optional) port number. Thus, in some
   addresses, a colon followed by a decimal number could ambiguously
   be interpreted as a port designator or as a part of the IPv6
   address.

   Even if there were no ambiguity, this syntax is incompatible with a
   many deployed applications that parse (but do not resolve) URLs,
   including many CGI scripts, robots, search engines, and so forth.

3. Syntax

   This specification defines a simple, safe representation for IPv6
   addresses within URLs, by defining a syntax which will look like a
   domain name to otherwise unaware software.

   The syntax is best described as a transformation of the
   normal IPv6 syntax as defined in section 2.2 of [RFC2373];
   starting with such an address:

     1) replace every colon ":" with a "-"
     2) append ".ipv6" to the end

   Thus, an HTTP service available at port 70 of IPv6 address
   "ABCD:EF01::2345:10.9.8.7" could be written as

        http://ABCD-EF01--2345-10.9.8.7.ipv6:70/

   This syntax should always be used. Internet software that resolves
   host names and addresses in URLs should be modified to recognize
   the "ipv6" pseudo-domain.

4. IANA considerations

   The Internet Assigned Names Authority is requested to reserve
   the "ipv6" pseudo-domain for the purpose outlined in this memo.

5. References

[RFC2396] R. Fielding, L. Masinter, T. Berners-Lee, "Uniform Resource
          Identifiers: Generic Syntax", August, 1998.

[RFC2373] R. Hinden, S. Deering. "IP Version 6 Addressing
          Architecture", July, 1998.


6. Authors' Addresses

   Larry Masinter
   Xerox Palo Alto Research Center
   3333 Coyote Hill Road
   Palo Alto, CA 94034, USA
   Fax: +1 650 812 4365
   EMail: masinter@parc.xerox.com

   James Gettys
   MIT Laboratory for Computer Science
   545 Technology Square
   Cambridge, MA 02139, USA
   Fax: +1 617 258 8682
   Email: jg@w3.org

   Brian Carpenter
   IBM United Kingdom Laboratories
   MP 185, Hursley Park
   Winchester, Hampshire SO21 2JN, UK
   Email: brian@hursley.ibm.com


7. Full Copyright Statement

   Copyright (C) The Internet Society (1997).  All Rights Reserved.

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