| < draft-iab-dns-zone-codepoint-pples-01.txt | draft-iab-dns-zone-codepoint-pples-02.txt > | |||
|---|---|---|---|---|
| Network Working Group A. Sullivan | Network Working Group A. Sullivan | |||
| Internet-Draft Dyn, Inc. | Internet-Draft Dyn, Inc. | |||
| Intended status: Informational D. Thaler | Intended status: Informational D. Thaler | |||
| Expires: June 7, 2013 Microsoft | Expires: August 3, 2013 Microsoft | |||
| J. Klensin | J. Klensin | |||
| O. Kolkman | O. Kolkman | |||
| NLnet Labs | NLnet Labs | |||
| December 4, 2012 | January 30, 2013 | |||
| Principles for Unicode Code Point Inclusion in Labels in the DNS | Principles for Unicode Code Point Inclusion in Labels in the DNS | |||
| draft-iab-dns-zone-codepoint-pples-01 | draft-iab-dns-zone-codepoint-pples-02 | |||
| Abstract | Abstract | |||
| IDNA makes available to DNS zone administrators a very wide range of | IDNA makes available to DNS zone administrators a very wide range of | |||
| Unicode code points. Most operators of zones should probably not | Unicode code points. Most operators of zones should probably not | |||
| permit registration of U-labels using the entire range. This is | permit registration of U-labels using the entire range. This is | |||
| especially true of zones that accept registrations across | especially true of zones that accept registrations across | |||
| organizational boundaries, such as top-level domains and, most | organizational boundaries, such as top-level domains and, most | |||
| importantly, the root. It is unfortunately not possible to generate | importantly, the root. It is unfortunately not possible to generate | |||
| algorithms to determine whether permitting a code point presents a | algorithms to determine whether permitting a code point presents a | |||
| skipping to change at page 1, line 45 ¶ | skipping to change at page 1, line 45 ¶ | |||
| Internet-Drafts are working documents of the Internet Engineering | Internet-Drafts are working documents of the Internet Engineering | |||
| Task Force (IETF). Note that other groups may also distribute | Task Force (IETF). Note that other groups may also distribute | |||
| working documents as Internet-Drafts. The list of current Internet- | working documents as Internet-Drafts. The list of current Internet- | |||
| Drafts is at http://datatracker.ietf.org/drafts/current/. | Drafts is at http://datatracker.ietf.org/drafts/current/. | |||
| Internet-Drafts are draft documents valid for a maximum of six months | Internet-Drafts are draft documents valid for a maximum of six months | |||
| and may be updated, replaced, or obsoleted by other documents at any | and may be updated, replaced, or obsoleted by other documents at any | |||
| time. It is inappropriate to use Internet-Drafts as reference | time. It is inappropriate to use Internet-Drafts as reference | |||
| material or to cite them other than as "work in progress." | material or to cite them other than as "work in progress." | |||
| This Internet-Draft will expire on June 7, 2013. | This Internet-Draft will expire on August 3, 2013. | |||
| Copyright Notice | Copyright Notice | |||
| Copyright (c) 2012 IETF Trust and the persons identified as the | Copyright (c) 2013 IETF Trust and the persons identified as the | |||
| document authors. All rights reserved. | document authors. All rights reserved. | |||
| This document is subject to BCP 78 and the IETF Trust's Legal | This document is subject to BCP 78 and the IETF Trust's Legal | |||
| Provisions Relating to IETF Documents | Provisions Relating to IETF Documents | |||
| (http://trustee.ietf.org/license-info) in effect on the date of | (http://trustee.ietf.org/license-info) in effect on the date of | |||
| publication of this document. Please review these documents | publication of this document. Please review these documents | |||
| carefully, as they describe your rights and restrictions with respect | carefully, as they describe your rights and restrictions with respect | |||
| to this document. Code Components extracted from this document must | to this document. Code Components extracted from this document must | |||
| include Simplified BSD License text as described in Section 4.e of | include Simplified BSD License text as described in Section 4.e of | |||
| the Trust Legal Provisions and are provided without warranty as | the Trust Legal Provisions and are provided without warranty as | |||
| skipping to change at page 3, line 8 ¶ | skipping to change at page 3, line 8 ¶ | |||
| 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 | 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 | |||
| 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 | 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 | |||
| 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 | 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 | |||
| 11. IAB Members at the Time of This Writing . . . . . . . . . . . 10 | 11. IAB Members at the Time of This Writing . . . . . . . . . . . 10 | |||
| 12. Informative References . . . . . . . . . . . . . . . . . . . . 10 | 12. Informative References . . . . . . . . . . . . . . . . . . . . 10 | |||
| Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 | Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 | |||
| 1. Introduction | 1. Introduction | |||
| Operators of a DNS zone need to set policies around what Unicode code | Operators of a DNS zone need to set policies around what Unicode code | |||
| points are allowed in labels in that zone. Typically there a number | points are allowed in labels in that zone. Typically there are a | |||
| of important goals to consider when constructing such policies. | number of important goals to consider when constructing such | |||
| These include, for instance, possible visual confusability between | policies. These include, for instance, avoiding possible visual | |||
| two labels, possible confusion between Fully-Qualified Domain Names | confusability between two labels, avoiding possible confusion between | |||
| (FQDNs) and IP address literals, and other usability and | Fully-Qualified Domain Names (FQDNs) and IP address literals, | |||
| accessibility issues. | accessibility to the disabled (see [WCAG20] for some discussion in a | |||
| web context), and other usability issues. | ||||
| This document provides a set of principles that zone operators can | This document provides a set of principles that zone operators can | |||
| use to construct their code point policies in order to improve | use to construct their code point policies in order to improve | |||
| usability and clarity and thereby reduce confusion. | usability and clarity and thereby reduce confusion. | |||
| 1.1. Terminology | 1.1. Terminology | |||
| This document uses the following terms. | This document uses the following terms. | |||
| A-label: an LDH label that starts with "xn--" and meets all the | A-label: an LDH label that starts with "xn--" and meets all the | |||
| skipping to change at page 8, line 37 ¶ | skipping to change at page 8, line 37 ¶ | |||
| the list of code points to be permitted should change very slowly, if | the list of code points to be permitted should change very slowly, if | |||
| at all, and usually only in the direction of permitting an addition | at all, and usually only in the direction of permitting an addition | |||
| as time and experience indicates that inclusion of such a code point | as time and experience indicates that inclusion of such a code point | |||
| is both safe and consistent with these principles. | is both safe and consistent with these principles. | |||
| 5. Principle Specific to the Root Zone | 5. Principle Specific to the Root Zone | |||
| 5.1. Letter Principle | 5.1. Letter Principle | |||
| There is a note in [RFC1123] that top-level labels "will be | There is a note in [RFC1123] that top-level labels "will be | |||
| alphabetic". In the absensce of widespread agreement about the force | alphabetic". In the absence of widespread agreement about the force | |||
| of that note, prudence suggests that U-labels in the root zone should | of that note, prudence suggests that U-labels in the root zone should | |||
| exclude code points that are not normally used to write words, or | exclude code points that are not normally used to write words, or | |||
| that are in some cases normally used for purposes other than writing | that are in some cases normally used for purposes other than writing | |||
| words. This is not the same as using Unicode's General_Category to | words. This is not the same as using Unicode's General_Category to | |||
| include only letters. It is a restriction that expands the possible | include only letters. It is a restriction that expands the possible | |||
| class of included code points beyond the Unicode letters, but only | class of included code points beyond the Unicode letters, but only | |||
| expands so far as to include the things that are normally used to | expands so far as to include the things that are normally used to | |||
| create words. Under this principle, code points with (for example) | create words. Under this principle, code points with (for example) | |||
| General_Category Mn (Nonspacing_Mark) might be included -- but only | General_Category Mn (Nonspacing_Mark) might be included -- but only | |||
| those that are used to write words and not (for instance) musical | those that are used to write words and not (for instance) musical | |||
| skipping to change at page 12, line 5 ¶ | skipping to change at page 11, line 43 ¶ | |||
| Internationalized Domain Names in Applications (IDNA) | Internationalized Domain Names in Applications (IDNA) | |||
| 2008", RFC 5895, September 2010. | 2008", RFC 5895, September 2010. | |||
| [RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in | [RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in | |||
| Internationalization in the IETF", BCP 166, RFC 6365, | Internationalization in the IETF", BCP 166, RFC 6365, | |||
| September 2011. | September 2011. | |||
| [UTR36] Davis, M. and M. Suignard, "Unicode Security | [UTR36] Davis, M. and M. Suignard, "Unicode Security | |||
| Considerations", Unicode Technical Report #36, July 2012. | Considerations", Unicode Technical Report #36, July 2012. | |||
| [WCAG20] "Web Content Accessibility Guidelines (WCAG) 2.0", | ||||
| December 2008. | ||||
| Authors' Addresses | Authors' Addresses | |||
| Andrew Sullivan | Andrew Sullivan | |||
| Dyn, Inc. | Dyn, Inc. | |||
| 150 Dow St | 150 Dow St | |||
| Manchester, NH 03101 | Manchester, NH 03101 | |||
| U.S.A. | U.S.A. | |||
| Email: asullivan@dyn.com | Email: asullivan@dyn.com | |||
| End of changes. 8 change blocks. | ||||
| 12 lines changed or deleted | 16 lines changed or added | |||
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