Network Working Group S. Sharikov
Internet-Draft Regtime Ltd
Intended status: Informational D. Miloshevic
Expires: November 13, 2010 Afilias
J. Klensin
May 12, 2010
Internationalized Domain Names Registration and Administration
Guideline for European languages using Cyrillic
draft-sharikov-idn-reg-05.txt
Abstract
This document is a guideline for Registries and Registrars on
registering internationalized domain names (IDNs) based on (in
alphabetical order) Bosnian, Bulgarian, Byelorussian, Kildin Sami,
Macedonian, Montenegrin, Russian, Serbian, and Ukrainian languages in
a DNS zone. For completeness of the "European" languages, it also
discusses the additional characters needed for Moldovan when it is
written in Cyrillic script. It describes appropriate characters for
registration and variant considerations for characters from Greek and
Latin scripts with similar appearances and/or derivations.
Status of this Memo
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This Internet-Draft will expire on November 13, 2010.
Copyright Notice
Copyright (c) 2010 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Similar Characters and Variants . . . . . . . . . . . . . 5
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6
2. Languages and Characters . . . . . . . . . . . . . . . . . . . 6
2.1. Bosnian and Serbian . . . . . . . . . . . . . . . . . . . 7
2.2. Bulgarian . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3. Byelorussian . . . . . . . . . . . . . . . . . . . . . . . 7
2.4. Kildin Sami . . . . . . . . . . . . . . . . . . . . . . . 7
2.5. Macedonian . . . . . . . . . . . . . . . . . . . . . . . . 8
2.6. Moldovan . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.7. Montenegrin . . . . . . . . . . . . . . . . . . . . . . . 8
2.8. Russian . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.10. Ukrainian . . . . . . . . . . . . . . . . . . . . . . . . 9
3. Language-based Tables . . . . . . . . . . . . . . . . . . . . 9
4. Table processing rules . . . . . . . . . . . . . . . . . . . . 9
5. Table Format . . . . . . . . . . . . . . . . . . . . . . . . . 10
6. Steps after registering an input label . . . . . . . . . . . . 10
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . . 12
Appendix A. European Cyrillic Character Tables . . . . . . . . . 13
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 18
B.1. Changes between -02 and -03 and comments about -03 . . . . 19
B.2. Changes between -03 and -04 . . . . . . . . . . . . . . . 19
B.3. Changes between -04 and -05 . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
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1. Introduction
Cyrillic is one of a fairly small number of scripts that are used,
with different subsets of characters, to write a large number of
languages, some of which are not closely related to the others. When
those languages might be used together in a zone (typical of generic
TLDs (gTLDs) but likely in other zones both at and below the root),
special considerations for intermixing characters may apply.
Cyrillic also has the property that, while it is usually considered a
separate script from the Latin (Roman) and Greek ones, it shares many
characters with them, creating opportunities for visual confusion.
Those difficulties are especially pronounced with "all of Cyrillic"
is used rather than only the characters associated with a particular
language.
This specification provides guidelines for the use of Cyrillic, as
encoded in Unicode [Unicode52] with internationalized domain name
(IDN) labels derived from most "European" languages that use the
script (use of the term "European" is a convenience, since there is
disagreement about the relevant boundaries for different purposes
and, of course, much of Russia lies within geological Asia).
Specifically it covers (in alphabetic order) Bosnian, Bulgarian,
Byelorussian, the Kildin member of the Sami (often written "Saami")
language family, Macedonian, Montenegrin, Russian, Serbian, and
Ukrainian. Supplemental tables, based on information in the Unicode
Standard and a recently-completed Montenegrin government standard
[MontenegrinChars] are provided for use with Montenegrin. Moldovan
is no longer in official use with Cyrillic script and no
registrations are considered likely in Cyrillic, at least within the
relevant ccTLD. Languages of Asia that use Cyrillic are not
considered here and should be the subject of separate specifications.
While Cyrillic script is the primary one used for many of the
relevant languages and countries, Latin script is often used instead
of, or in combination with, it. Standard keyboards used in most of
the countries have both Cyrillic and Latin characters. Therefore
some registries could use Latin scripts for domain names registration
in their zones. From time to time, some registries and users have
claimed that there is a requirement for mixing Cyrillic and Latin
characters in the same label. We strongly recommend against such
mixing as user confusion is almost certain to result. In addition,
registries that support many scripts will probably encounter the need
to support labels in Greek or Latin scripts as well as Cyrillic and a
large number of character forms are shared among those three scripts.
Because the DNS has no way for the end-user to distinguish among the
languages that might have been used to inspire a particular label, it
seems useful to treat the characters of a large number of languages
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that use Cyrillic in their writing systems together, rather than
trying to differentiate them. The discussion and tables in this
specification should provide a foundation for developing more
restrictive rules for zones in which only a single language is likely
to be used, but it does not specify those language-specific rules.
Readers of this document should be aware that its recommendations are
about use in DNS labels. The orthography for some of the languages
involved, especially Kildin Sami, is not completely standardized and
local usage sometimes permits substitution of Latin-based characters
for their Cyrillic equivalents. Unless they are required by official
orthographies, those substitutions should generally be avoided in DNS
labels because of the risk of additional user confusion with the
similar-appearing Latin characters.
1.1. Similar Characters and Variants
For some human languages, there are characters and/or strings that
have equivalent or near-equivalent meanings. If someone is allowed
to register a name with such a character or string, the registry
might want to automatically register all the names that have the same
meaning in that language. Further, some registries might want to
restrict the set of characters to be registered for language-based
reasons. In addition, IDNA [RFC3490] allows the use of thousands of
non-alphanumeric characters, and some zone administrators will want
to prohibit some or all of these characters.
So-called "variant techniques", introduced in [RFC3743] and
generalized beyond East Asian language in [RFC4290], describe ways of
registering IDN domain names to decrease the risk of
misunderstandings, cybersquatting, and other forms of confusion.
The tables below (Appendix A) identify confusable characters in Latin
and Greek scripts that might be easily confused with Cyrillic ones.
As with variant approaches for other scripts (e.g., see RFC 4713 for
the Chinese language [RFC4713] or RFC 5564 for the Arabic language
[RFC5564]), this document identifies sets of characters that need
special consideration and provides information about them. A
registry that handles names using these characters can then make a
policy decision about how to actually handle them. The options for
those policy decisions would include automatically registering all
look-alike string to the same registrant, registering one such string
and blocking the others, and so on.
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1.2. Terminology
The terminology that follows is derived from [RFC3743] and [RFC4290],
but this specification does not depend on them. All characters
listed here have been verified to be "PVALID" under the recently-
adopted IDNA2008 specification [IDNA2008-Defs].
A "string" is a sequence of one or more characters.
This document discusses characters that have equivalent or near-
equivalent characters or strings. The "base character" is the
character that has one or more equivalents; the "variant(s)" are the
character(s) and/or string(s) that are equivalent to the base
character.
A "registration bundle" is the set of all labels that comes from
expanding all base characters for a single name into their variants.
A registry is the administrative authority for a DNS zone. That is,
the registry is the body that makes and enforces policies that are
used in a particular zone in the DNS. The term "registry" applies to
all zones in the DNS, not only those that exist at the top level.
2. Languages and Characters
In the interest of clarity and balance, this document describes a
"Base Cyrillic" set of twenty-three characters for use in comparing
the character usage for Russian and Central European languages that
use Cyrillic. The balance of this section compares the character
usage of the individual languages in that group.
"Base Cyrillic" consists of the following Unicode code points (names
associated with these code points and those below appear in
Appendix A): U+0430, U+0431, U+0432, U+0433, U+0434, U+0435, U+0436,
U+0437, U+043A, U+043B, U+043C, U+043D, U+043E, U+043F, U+0440,
U+0441, U+0442, U+0443, U+0444, U+0445, U+0446, U+0447, U+0448.
In addition, modern writing systems that use Cyrillic do not have
digits separate from the "European" ones used with Latin characters.
For registries that permit digits to appear in domain name labels,
the "Base Cyrillic" code point listed above should be considered to
include U+0030, U+0031, U+0032, U+0033, U+0034, U+0035, U+0036,
U+0037, U+0038, and U+0039 (Digit Zero, and Digit One, through Digit
Nine). The Hyphen-Minus character (U+0029) may also be used.
It is worth noting that the EU top-level domain registry allows
Cyrillic registrations using 32 code points [EU-registry]. That list
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is sufficient for some of the languages listed here but not for
others.
The individual languages that are the focus of this specification are
discussed below (in English alphabetical order):
2.1. Bosnian and Serbian
Bosnian and Serbian have 30 letters in the alphabet and the
additional seven characters to the base of 23 shared Cyrillic
characters: U+0438, U+0458, U+0452, U+0459, U+045A, U+045B, U+045F.
2.2. Bulgarian
The Bulgarian alphabet has thirty characters, seven in addition to
the basic twenty-three: U+0438, U+0439, U+0449, U+044A, U+044C,
U+044E, U+044F.
2.3. Byelorussian
Byerlorussian alphabet has 32 characters, i.e., nine characters in
addition to the Base Cyrillic set of 23 characters: U+0451, U+0456,
U+0439, U+044B, U+044C, U+045E, U+044D, U+044E, U+044F.
2.4. Kildin Sami
The phonetics of the Kildin Sami are quite complex and not easily
represented in Cyrillic (see, e.g., [Kert]). The orthography is not
standardized and the writing system may best be thought of as an
attempt to transcribe the language phonetically (primary in Latin
script in the 1930s but in Cyrillic more recently). Different
scholars have reported different numbers of phonemes, further
complicating the transcription process. Kertom identifies 53
consonants with long-short distinctions and, in many cases, hard-soft
ones. He also identifies ascending and descending diphthongs and one
triphtong as well as more common short and long vowels.
The primary reference for Kildin Sami that is apparently used by Sami
language(s) experts in Scandinavian countries [Riessl07] and the
references it cites, uses 56 characters, 33 of which do not appear in
the basic set. Eight* of these characters have no precomposed forms
in Unicode and hence must be written as a two-code-point sequence
including U+0304 (Combining Macron). Using parentheses to make the
two-code-point sequences more obvious, the additional characters are:
(U+0430 U+0304)*, (U+0435 U+0304)*, U+0438, U+0439, (U+043E U+0304),
U+044A, U+044B, (U+044B U+0304), U+044C, U+044D, (U+044D U+0304),
U+044E, (U+044E U+0304), U+044F, (U+044F U+0304), U+0451, (U+0451
U+0304), U+0458, U+048B, U+048D, U+048F, U+04BB, U+04C6, U+04C8,
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U+04CA, U+04CE, U+04D3, U+04E3, U+04E7, U+04ED, U+04EF, U+04F1,
U+04F9.
* These characters, CYRILLIC SMALL LETTER A with a COMBINING MACRON
and CYRILLIC SMALL LETTER IE with a COMBINING MACRON,
respectively, have the same visual appearance as LATIN SMALL
LETTER A WITH MACRON (U+0101) and LATIN SMALL LETTER E WITH MACRON
(U+0113). The combinations are not mapped to the Latin character
sequences by NFC (or NFKC) normalization. Substitution of the
Latin sequence for the second of these is specified by some
sources including Riessler [Riessl07]. Substitution of the Latin
character codepoint for the first sequence is not specified in any
reference we found, but the relationship is obvious and may occur
outside the user's control based on the keyboard or input
functions in use. However, U+0101 and U+0113 are Latin Script
characters so, if either is used, any tests on homogeneity of the
script within a label need to be made with care. If some input
systems produce U+0113 (or U+0101) and others produce the two-
character combining sequence, a variant approach may be
appropriate.
Similar issues may apply to other Kildin Sami characters
constructed with combining sequences.
The key references in Russian [Anto90], [Kert86], [Kuru85] all
propose slightly different character tables relative to each other
and to Riessler's list. Because the latter list appears to be more
comprehensive and to represent more recent scholarship, we have based
the tables in this document on it. We recommend, however, that
registries review these recommendations and the relevant papers
should registration requests for Kildin Sami actually appear.
2.5. Macedonian
Macedonian has 31 characters in the alphabet. This is eight in
addition to the basic set: U+0438, U+0458, U+0452, U+0459, U+045A,
U+045C, U+045F, U+0491, U+0455.
2.6. Moldovan
Cyrillic is no longer in everyday use for Moldovan, so no IDN
registrations are anticipated.
2.7. Montenegrin
According to the most recent, and now final, government specification
[MontenegrinChars], Montenegrin has 32 characters in its alphabet,
including two that have no precomposed forms in Unicode. This is
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nine in addition to the basic set and two in addition to Bosnian and
Serbian: U+0437 U+0302, U+0438, U+0441 U+0302, U+0452, U+0458,
U+0459, U+045A, U+045B, U+045F.
See Bosnian, Section 2.1, above.
2.8. Russian
The current Russian alphabet has 33 characters, consisting of the
Base Cyrillic set plus an additional ten characters: U+0451, U+0438,
U+0439, U+0449, U+044A, U+044B, U+044C, U+044D, U+044E, U+044F.
2.9. Serbian
See Bosnian, Section 2.1, above.
2.10. Ukrainian
The character list for modern Ukrainian has apparently not completely
stabilized. Some references claim 31 characters and therefore an
additional 8 characters to the Base Cyrillic set of 23. Others claim
33, adding U+0438 and U+0439 and replacing U+044A (hard sign) with
U+044C (soft sign), for a total of an additional 11 characters as
compared to the Base Cyrillic set. Unless better information is
available, the prudent registry should probably assume that all 34
characters are in use, i.e., the Base Cyrillic set plus U+0438,
U+0439, U+0454, U+0456, U+0457, U+0491, U+0449, U+044A, U+044C,
U+044E, U+044F.
3. Language-based Tables
The registration strategy described in this document uses a table
that lists all characters allowed for input and any variants of those
characters. Note that the table lists all characters allowed, not
only the ones that have variants.
4. Table processing rules
The input to the process is called the "input label". The output of
the process is either failure (the input label cannot be registered
at all), or a registration bundle that contains one or more labels in
A-label form.
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5. Table Format
The table in Appendix A consists of four columns. The first and
second identify the Cyrillic character and the third and fourth
identify Latin or Greek characters that might be easily confused with
them visually. If both a Latin and Greek character are present, the
Greek one appears in the third and fourth columns on the subsequent
line (with "..." in the first column to indicate more information
about the character specified on the previous line). Variants needed
only because of case folding are shown with "+++" in the first
column, as noted in the table.
Each character in the table is given in the "U+" notation for Unicode
characters followed, in the next column, by its name as shown in the
Unicode Standard. For easy reference, the characters are listed in
the order in which they appear in the Unicode Standard.
The table does not, and any future revision MUST NOT, have more than
one entry for a particular base character.
6. Steps after registering an input label
A registry has at least three policy options for handling the cases
where the registration bundle has more than one label. These
options, and their key implications, are:
o Allocate all labels to the same registrant, making the zone
information identical to that of the input label.
This option will cause end users to be able to find names with
variants more easily, but will result in larger zone files. In
principle, the zone file could become so large that it could
negatively affect the ability of the registry to perform name
resolution.
o Block all labels so they cannot be registered in the future.
This option does not increase the size of the zone file, but it
may cause end users to not be able to find names with variants
that they would expect.
o Allocate some labels and block some other labels.
This option is likely to cause the most confusion with users
because including some variants will cause a name to be found,
bout using other variants will cause the name to be not found.
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With any of these three options, the registry MUST keep a database
that links each label in the registration bundle to the input label.
This link needs to be maintained so that changes in the non-DNS
registration information (such as the label's owner name and address)
is reflected in every member of the registration bundle as well.
7. Acknowledgments
Support from Afilias for a major portion of this work is appreciated.
The material on Kildin Sami would not have been possible without the
efforts of Cary Karp for his help directly and his pointer to
[Riessl07] and from Vladimir Shadrunov and Sergey Nikolaevich
Teryoshkin for their own analyses and references to [Anto90],
[Kert86], and [Kuru85] and partial translations from them. We are
grateful for their efforts that facilitated treating it nearly the
same way as other actively-used European languages that use Cyrillic
script.
Careful reading of late drafts by Bill McQuillan and Alexey Melnikov
identified a number of editorial problems, some of which might not
have been caught otherwise.
8. References
8.1. Normative References
[RFC3490] Faltstrom, P., Hoffman, P., and A. Costello,
"Internationalizing Domain Names in Applications (IDNA)",
RFC 3490, March 2003.
[RFC3491] Hoffman, P. and M. Blanchet, "Nameprep: A Stringprep
Profile for Internationalized Domain Names (IDN)",
RFC 3491, March 2003.
[Unicode52]
The Unicode Consortium, "The Unicode Standard, Version
5.2.0", 2009.
Defined by: The Unicode Standard, Version 5.0, Boston, MA,
Addison-Wesley, 2007, ISBN 0-321-48091-0, as amended by
Unicode 5.1.0
(http://www.unicode.org/versions/Unicode5.1.0/) and
Unicode 5.2.0
(http://www.unicode.org/versions/Unicode5.2.0/).
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8.2. Informative References
[Anto90] Antonova, A., "Sami primer", 1990.
Published in Russian, no authoritative translation is
known.
[EU-registry]
European Registry of Internet Domain Names (EURid), ".eu
Supported Characters", January 2010, <http://www.eurid.eu/
en/eu-domain-names/technical-limitations/
supported-characters>.
[IDNA2008-Defs]
Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework",
January 2010, <https://datatracker.ietf.org/drafts/
draft-ietf-idnabis-defs/>.
[Kert] Kertom, G., "Kildin dialect of the Sami language".
Published in Russian, no authoritative translation is
known.
[Kert86] Kertom, G., "Sami-Russian and Russian-Sami dictionary",
1986.
Published in Russian, no authoritative translation is
known.
[Kuru85] Kuruch, R., "Sami-Russian dictionary", 1985.
Published in Russian, no authoritative translation is
known.
[MontenegrinChars]
Crna Gora Ministarstvo prosvjete i nauke (Ministry of
Science and Education, Montenegro), "Pravopis Crnogorskoga
Jezika I", 2009, <http://www.gov.me/files/1248442673.pdf>.
In Montenegrin, no known English translation. See
especially the table on page 8.
[OmniglotSaami]
Ager, S., "Sami (Saami)", 2009,
<http://www.omniglot.com/writing/saami.htm>.
[RFC3743] Konishi, K., Huang, K., Qian, H., and Y. Ko, "Joint
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Engineering Team (JET) Guidelines for Internationalized
Domain Names (IDN) Registration and Administration for
Chinese, Japanese, and Korean", RFC 3743, April 2004.
[RFC4290] Klensin, J., "Suggested Practices for Registration of
Internationalized Domain Names (IDN)", RFC 4290,
December 2005.
[RFC4713] Lee, X., Mao, W., Chen, E., Hsu, N., and J. Klensin,
"Registration and Administration Recommendations for
Chinese Domain Names", RFC 4713, October 2006.
[RFC5564] El-Sherbiny, A., Farah, M., Oueichek, I., and A. Al-Zoman,
"Linguistic Guidelines for the Use of the Arabic Language
in Internet Domains", RFC 5564, February 2010.
[Riessl07]
Riessler, M., "Kola Saami character chart (draft)",
November 2007.
Appendix A. European Cyrillic Character Tables
These tables are constructed on the basis of the characters that can
actually occur in the DNS, i.e., those that can be obtained by
applying the ToUnicode operation of RFC 3490 or the U-label
transformation [IDNA2008-Defs] to an ACE-encoded label (A-label) as
defined in those specifications. If the characters that can be
mapped into those characters are to be considered instead, then the
number of variants would increase considerably. For example, while
Cyrillic Small Letter A and Greek Small Letter Alpha are readily
distinguished visually, their capital letter equivalents are not, so,
if the extended set of Nameprep [RFC3491] mappings are considered,
the two small letters must be considered variants of each other.
These additional, possibly-required, variants are shown below with
"+++" in the first column of the table.
Characters needed for European languages, other than Moldovan and
Sami, written in Cyrillic.
+----------+------------------------+---------+---------------------+
| Cyrillic | Unicode Name | Variant | Unicode Name |
| Char | | | |
+----------+------------------------+---------+---------------------+
| U+0430 | CYRILLIC SMALL LETTER | U+0061 | LATIN SMALL LETTER |
| | A | | A |
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| +++ | | U+03B0 | GREEK SMALL LETTER |
| | | | ALPHA |
| U+0431 | CYRILLIC SMALL LETTER | | |
| | BE | | |
| U+0432 | CYRILLIC SMALL LETTER | U+0062 | LATIN SMALL LETTER |
| | VE | | B |
| +++ | | U+03B2 | GREEK SMALL LETTER |
| | | | BETA |
| U+0433 | CYRILLIC SMALL LETTER | U+0072 | LATIN SMALL LETTER |
| | GHE | | R |
| +++ | | U+03B3 | GREEK SMALL LETTER |
| | | | GAMMA |
| U+0434 | CYRILLIC SMALL LETTER | | |
| | DE | | |
| +++ | | U+03B4 | GREEK SMALL LETTER |
| | | | DELTA |
| U+0435 | CYRILLIC SMALL LETTER | U+0065 | LATIN SMALL LETTER |
| | IE | | E |
| +++ | | U+03B5 | GREEK SMALL LETTER |
| | | | EPSILON |
| U+0436 | CYRILLIC SMALL LETTER | | |
| | ZHE | | |
| U+0437 | CYRILLIC SMALL LETTER | | |
| | ZE | | |
| U+0438 | CYRILLIC SMALL LETTER | U+0075 | LATIN SMALL LETTER |
| | I | | U |
| U+0439 | CYRILLIC SMALL LETTER | | |
| | SHORT I | | |
| U+043A | CYRILLIC SMALL LETTER | U+006B | LATIN SMALL LETTER |
| | KA | | K |
| ... | | U+03BA | GREEK SMALL LETTER |
| | | | KAPPA |
| U+043B | CYRILLIC SMALL LETTER | | |
| | EL | | |
| +++ | | U+039B | GREEK SMALL LETTER |
| | | | LAMBDA |
| U+043C | CYRILLIC SMALL LETTER | U+006D | LATIN SMALL LETTER |
| | EM | | M |
| +++ | | U+03BC | GREEK SMALL LETTER |
| | | | MU |
| U+043D | CYRILLIC SMALL LETTER | U+0068 | LATIN CAPITAL |
| | EN | | LETTER H (and SMALL |
| | | | LETTER H in some |
| | | | fonts) |
| +++ | | U+03B7 | GREEK SMALL LETTER |
| | | | ETA |
| U+043E | CYRILLIC SMALL LETTER | U+006F | LATIN SMALL LETTER |
| | O | | O |
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| ... | | U+03BF | GREEK SMALL LETTER |
| | | | OMICRON |
| U+043F | CYRILLIC SMALL LETTER | U+006E | LATIN SMALL LETTER |
| | PE | | N |
| ... | | U+03C0 | GREEK SMALL LETTER |
| | | | PI |
| U+0440 | CYRILLIC SMALL LETTER | U+0070 | LATIN SMALL LETTER |
| | ER | | P |
| ... | | U+03C1 | GREEK SMALL LETTER |
| | | | RHO |
| U+0441 | CYRILLIC SMALL LETTER | U+0063 | LATIN SMALL LETTER |
| | ES | | C |
| U+0442 | CYRILLIC SMALL LETTER | U+0074 | LATIN SMALL LETTER |
| | TE | | T |
| +++ | | U+03C4 | GREEK SMALL LETTER |
| | | | TAU |
| U+0443 | CYRILLIC SMALL LETTER | U+0079 | LATIN SMALL LETTER |
| | U | | Y |
| +++ | | U+03C5 | GREEK SMALL LETTER |
| | | | UPSILON |
| U+0444 | CYRILLIC SMALL LETTER | U+03D5 | GREEK PHI SYMBOL |
| | EF | | |
| +++ | | U+03C6 | GREEK SMALL LETTER |
| | | | PHI |
| U+0445 | CYRILLIC SMALL LETTER | U+0078 | LATIN SMALL LETTER |
| | HA | | X |
| ... | | U+03C7 | GREEK SMALL LETTER |
| | | | CHI |
| U+0446 | CYRILLIC SMALL LETTER | | |
| | TSE | | |
| U+0447 | CYRILLIC SMALL LETTER | | |
| | CHE | | |
| U+0448 | CYRILLIC SMALL LETTER | | |
| | SHA | | |
| U+0449 | CYRILLIC SMALL LETTER | | |
| | SHCHA | | |
| U+044A | CYRILLIC SMALL LETTER | | |
| | HARD SIGN | | |
| U+044B | CYRILLIC SMALL LETTER | | |
| | YERU | | |
| U+044C | CYRILLIC SMALL LETTER | U+0062 | LATIN SMALL LETTER |
| | SOFT SIGN | | B |
| U+044D | CYRILLIC SMALL LETTER | | |
| | E | | |
| U+044E | CYRILLIC SMALL LETTER | | |
| | YU | | |
| U+044F | CYRILLIC SMALL LETTER | | |
| | YA | | |
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| U+0451 | CYRILLIC SMALL LETTER | U+00EB | LATIN SMALL LETTER |
| | IO | | E WITH DIAERESIS |
| U+0452 | CYRILLIC SMALL LETTER | | |
| | DJE | | |
| U+0453 | CYRILLIC SMALL LETTER | | |
| | GJE | | |
| U+0454 | CYRILLIC SMALL LETTER | U+03B5 | GREEK SMALL LETTER |
| | UKRAINIAN IE | | EPSILON |
| U+0455 | CYRILLIC SMALL LETTER | U+0073 | LATIN SMALL LETTER |
| | DZE | | S |
| U+0456 | CYRILLIC SMALL LETTER | U+0069 | LATIN SMALL LETTER |
| | BYELORUSSIAN-UKRAINIAN | | I |
| | I | | |
| +++ | | U+03B9 | GREEK SMALL LETTER |
| | | | IOTA |
| U+0457 | CYRILLIC SMALL LETTER | U+03CA | GREEK SMALL LETTER |
| | UKRAINIAN YI | | IOTA WITH DIALYTIKA |
| +++ | | U+00EF | LATIN SMALL LETTER |
| | | | I WITH DIAERESIS |
| U+0458 | CYRILLIC SMALL LETTER | U+006A | LATIN SMALL LETTER |
| | JE | | J |
| ... | | U+03F3 | GREEK LETTER YOT |
| U+0459 | CYRILLIC SMALL LETTER | | |
| | LJE | | |
| U+045A | CYRILLIC SMALL LETTER | | |
| | NJE | | |
| U+045B | CYRILLIC SMALL LETTER | | |
| | TSHE | | |
| U+045C | CYRILLIC SMALL LETTER | | |
| | KJE | | |
| U+045D | CYRILLIC SMALL LETTER | | |
| | I WITH GRAVE | | |
| U+045E | CYRILLIC SMALL LETTER | | |
| | SHORT U | | |
| U+045F | CYRILLIC SMALL LETTER | | |
| | DZHE | | |
| U+0491 | CYRILLIC SMALL LETTER | | |
| | GHE WITH UPTURN | | |
| U+04C2 | CYRILLIC SMALL LETTER | | |
| | ZHE WITH BREVE | | |
+----------+------------------------+---------+---------------------+
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Additional characters needed for Moldovan written in Cyrillic.
+--------------+-----------------------------+---------+------------+
| Cyrillic | Unicode Name | Variant | Unicode |
| Char | | | Name |
+--------------+-----------------------------+---------+------------+
| U+04C2 | CYRILLIC SMALL LETTER ZHE | | |
| | WITH BREVE | | |
| U+0437 + | Cyrillic Small Letter ZE | | |
| U+0302 | with Acute | | |
| U+0441 + | Cyrillic Small Letter ES | | |
| U+0302 | with Acute | | |
+--------------+-----------------------------+---------+------------+
Additional characters needed for Kildin Sami written in Cyrillic.
+----------+---------------------+----------+-----------------------+
| Cyrillic | Unicode Name | Variant | Unicode Name |
| Char | | | |
+----------+---------------------+----------+-----------------------+
| U+0430 + | Cyrillic Small | U+0101 | LATIN SMALL LETTER A |
| U+0304 | Letter A with | | WITH MACRON |
| | Macron | | |
| ... | | U+03B0 + | Greek Small Letter |
| | | U+0304 | Alpha with Macron |
| U+0435 + | Cyrillic Small | U+0113 | LATIN SMALL LETTER E |
| U+0304 | Letter IE with | | WITH MACRON |
| | Macron | | |
| U+043E + | Cyrillic Small | U+014D | LATIN SMALL LETTER O |
| U+0304 | Letter O with | | WITH MACRON |
| | Macron | | |
| ... | | U+03BF + | Greek Small Letter |
| | | U+0304 | Omicron with Macron |
| U+044B + | Cyrillic Small | | |
| U+0304 | Letter YERU with | | |
| | Macron | | |
| U+044D + | Cyrillic Small | | |
| U+0304 | Letter E with | | |
| | Macron | | |
| U+044E + | Cyrillic Small | | |
| U+0304 | Letter YU with | | |
| | Macron | | |
| U+044F + | Cyrillic Small | | |
| U+0304 | Letter YA with | | |
| | Macron | | |
| U+0451 + | Cyrillic Small | U+00EB + | Latin Small Letter E |
| U+0304 | Letter IO with | U0304 | With Diaeresis and |
| | Macron | | Macron |
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| U+048B | CYRILLIC SMALL | | |
| | LETTER SHORT I WITH | | |
| | TAIL | | |
| U+048D | CYRILLIC SMALL | | |
| | LETTER SEMISOFT | | |
| | SIGN | | |
| U+048F | CYRILLIC SMALL | | |
| | LETTER ER WITH TICK | | |
| U+04BB | CYRILLIC SMALL | | |
| | LETTER SHHA | | |
| U+04C6 | CYRILLIC SMALL | | |
| | LETTER EL WITH TAIL | | |
| U+04C8 | CYRILLIC SMALL | | |
| | LETTER EN WITH HOOK | | |
| U+04CA | CYRILLIC SMALL | | |
| | LETTER EN WITH TAIL | | |
| U+04CE | CYRILLIC SMALL | | |
| | LETTER EM WITH TAIL | | |
| U+04D3 | CYRILLIC SMALL | U+00E4 | LATIN SMALL LETTER A |
| | LETTER A WITH | | WITH DIAERESIS |
| | DIAERESIS | | |
| U+04E3 | CYRILLIC SMALL | U+016B | LATIN SMALL LETTER U |
| | LETTER I WITH | | WITH MACRON |
| | MACRON | | |
| U+04E7 | CYRILLIC SMALL | U+00F6 | LATIN SMALL LETTER O |
| | LETTER O WITH | | WITH DIAERESIS |
| | DIAERESIS | | |
| U+04ED | CYRILLIC SMALL | | |
| | LETTER E WITH | | |
| | DIAERESIS | | |
| U+04EF | CYRILLIC SMALL | | |
| | LETTER U WITH | | |
| | MACRON | | |
| U+04F1 | CYRILLIC SMALL | | |
| | LETTER U WITH | | |
| | DIAERESIS | | |
| U+04F9 | CYRILLIC SMALL | | |
| | LETTER YERU WITH | | |
| | DIAERESIS | | |
+----------+---------------------+----------+-----------------------+
Appendix B. Change Log
RFC Editor: Please remove this appendix.
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B.1. Changes between -02 and -03 and comments about -03
o Updated references to Unicode 5.2.
o Updated information about Montenegrin and Kildin Sami.
o Removed note about IDNA2003, inserted a comment about IDNA2008
verification, and changed terminology to reflect IDNA2008 where
needed.
o Corrected an error for Bulgarian.
o Clarified role of this document vis-a-vis orthographies in use in
various places.
o Added text to clarify how the information in this document can be
used.
o Still reviewing Ukrainian (see Section 2.10) and mixed-script (see
Section 1) requirements (see -04 changes immediately below).
B.2. Changes between -03 and -04
o Revised text about mixed scripts slightly.
o Updated material on Kildin Sami.
o Improved the description of Ukrainian.
B.3. Changes between -04 and -05
o Fixed several errors in the comparison table appendix.
o Eliminated one residual case of IDNA2003 terminology.
Authors' Addresses
Sergey Sharikov
Regtime Ltd
Kalinina str.,14
Samara 443008
Russia
Phone: +7(846) 979-9039
Fax: +7(846)979-9038
Email: s.shar@regtime.net
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Desiree Miloshevic
Afilias
Oxford Internet Institute, 1 St. Giles
Oxford OX1 3JS
United Kingdom
Phone: +44 7973 987 147
Email: dmiloshevic@afilias.info
John C Klensin
1770 Massachusetts Ave, #322
Cambridge, MA 02140
USA
Phone: +1 617 491 5735
Email: john-ietf@jck.com
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