网络协议分析

1、语言鉴定标签语言鉴定标签喻清源 目录!1介绍!2语言标签!3语言标签的IANA 注册过程!4安全因素!5符号集合问题!6鸣谢!7作者地址!8参考文献1介绍!在我们这个星球上生存的人，过去的、现在的，已经使用了很多种语言。有很多原因使得我们必须在传送信息时确认所使用的语言。在有些时候，用多于一种语言描述信息也可行的，或者当提供了工具（比如字典）来辅助理解时也是可行的。另外，很多类型的信息处理都需要相应语言的知识，以便明确的阐释信息，进行处理。 1Introduction!Human beings on our planet have, past and present, used a numbe

2、r of languages. There are many reasons why one would want to identify the language used when presenting information.In some contexts, it is possible to have information available in more than one language, or it might be possible to provide tools (such as dictionaries) to assist in the understanding

3、 of a language.2语言标签!21 语言标签语法!22 语言标签来源!23 语言标签的选择!24 语言标签的意义!25 语言范围21 语言标签语法这种语言标签是由一或几部分构成的：一个主要语言辅标签（subtag），一系列（可能是空的）副标签(subsequent subtags)。 22 语言标签来源!根据本文档第三部分的规定，语言标签的名字域由IANA(Internet Assigned Numbers !Authority，见rfc 2860)管理。!下列规则适用于主要的标签：!-根据ISO 标准639中的分配，所有的含2个字母的标签被解释为，“表示语言中的名!称”（见ISO

4、 639），或是稍后被分配为维护和调节的标准体（注意，有一处校正尚未完成，!它将在ISO 639-1:2000中发布）。23 语言标签的选择!我们可能会偶尔遇到同样的文本有几种可能的标签的情况。!如果所有的用户发送同样的标签，在所有的文档中使用同一种语言的标签，那将是再好!不过的事了。如果应用程序有需要使这些规则在特定场合不适用，则应用协议必须指明是如!何变化的。24 语言标签的意义!语言标签总是定义一种语言，作为口语（书写语，标志，或者是信号）供人类进行交流与传递信息。计算机语言比如程序设计语言被明确的排除在外。没有什么可以保证有同样标签的语言之间的关系；特别地，也不能保证它们（语言）见可以

5、相互理解，尽管有时是可以的。25 语言范围!如果一个用户理解了一种特定的标签语言，那么，他将理解所有的以这种标签为前缀的语言）被分配到具体的语言，既不总是那么容易触类旁通的。一般来讲，前缀规则允许用户用这种前缀标签，在适当条件下。2.1 Language tag syntax!The language tag is composed of one or more parts: A primary language subtag and a (possibly empty) series of subsequent subtags.2.2 Language tag sources! The na

6、mespace of language tags is administered by the Internet Assigned Numbers Authority (IANA) RFC 2860 according to the rules in section 3 of this document.2.3 Choice of language tag! One may occasionally be faced with several possible tags for the same body of text.nteroperability is best served if al

7、l users send the same tag, and use the same tag for the same language for all documents. If an application has requirements that make the rules here inapplicable,the application protocol specification MUST specify how the procedure varies from the one given here.2.4 Meaning of the language tag! The

8、language tag always defines a language as spoken (or written, signed or otherwise signaled) by human beings for communication of information to other human beings. Computer languages such as programming languages are explicitly excluded. There is no guaranteed relationship between languages whose ta

9、gs begin with the same series of subtags; specifically, they are NOT guaranteed to be mutually intelligible, although it will sometimes be the case that they are.2.5 Language-range!This use of a prefix matching rule does not imply that language tags are assigned to languages in such a way that it is

10、 always true that if a user understands a language with a certain tag, then this user will also understand all languages with tags for which this tag is a prefix. The prefix rule simply allows the use of prefix tags if this is the case.3 语言标签的IANA 注册过程!任何人想要使用标签，包括在本文档2。2章没给出解释的，和已经注册IANA的，都必须要用到这里给

11、出的过程。3. IANA registration procedure for language tags The procedure given here MUST be used by anyone who wants to use a language tag not given an interpretation in chapter 2.2 of this document or previously registered with IANA4安全因素!关于语言标签安全问题的唯一的一份论文（自RFC 1766 发布以来），声明了“安全问题必将与此备忘录无关“，也讲到了关于语言范围的令

12、人满意的协商结论忽略发送者的国籍，也因此为监视确定了潜在的目标。4. Security Considerations!The only security issue that has been raised with language tags since the publication of RFC 1766, which stated that Security issues are believed to be irrelevant to this memo, is a concern with language ranges used in content negotiation -

13、that they may be used to infer the nationality of the sender, and thus identify potential targets for surveillance5 符号集合问题!语言标签可以总是以A-Z,a-z,0-9,和连词符号（HYPHEN-MINUS）表示，所以在语言标签的表示上不会有字符集合的问题争论。决定语言标签所使用的字符集的问题在这个备忘录中没有提到；然而，作出一个适于所有情况的正确的决定被认为将是不可能的，除非在文中更换语言时有相应的定义。（当决定一个引擎的字体是中文或是日文时，就会产生次最佳输出，就会遇到中日

14、文混合的文本）。5. Character set considerations! Language tags may always be presented using the characters A-Z, a-z, 0-9 and HYPHEN-MINUS, which are present in most character sets, so presentation of language tags should not have any character set issues.This document has benefited from many rounds of revi

15、ew and comment in various fora of the IETF and the Internet working groups.Any list of contributors is bound to be incomplete; please regard the following as only a selection from the group of people who have contributed to make this document what it is today.In alphabetical order:Glenn Adams, Tim B

16、erners-Lee, Marc Blanchet, Nathaniel Borenstein,Eric Brunner, Sean M. Burke, John Clews, Jim Conklin, Peter Constable, John Cowan, Mark Crispin, Dave Crocker, Mark Davis, Martin Duerst, Michael Everson, Ned Freed, Tim Goodwin, Dirk-Willem van Gulik, Marion Gunn, Paul Hoffman, Olle Jarnefors, Kent Ka

17、rlsson, John Klensin, Alain LaBonte, Chris Newman, Keith Moore, Masataka Ohta,Keld Jorn Simonsen, Otto Stolz, Rhys Weatherley, Misha Wolf, FrancoisYergeau and many, many others.Special thanks must go to Michael Everson, who has served as language tag reviewer for almost the complete period since the

18、 publication of RFC 1766, and has provided a great deal of input to this revision.7作者地址! Harald Tveit Alvestrand! Cisco Systems! Weidemanns vei 27! 7043 Trondheim! NORWAY! Phone: +47 73 50 33 52! EMail: HaraldAlvestrand.no8参考文献! ISO 639 ISO 639:1988 (E/F) - Code for the representation of names! of l

19、anguages - The International Organization for! Standardization, 1st edition, 1988-04-01 Prepared by! ISO/TC 37 - Terminology (principles and coordination).! Note that a new version (ISO 639-1:2000) is in! preparation at the time of this writing.!ISO 639-2 ISO 639-2:1998 - Codes for the representatio

20、n of names of! languages - Part 2: Alpha-3 code - edition 1, 1998-11-! 01, 66 pages, prepared by a Joint Working Group of ISO! TC46/SC4 and ISO TC37/SC2.!ISO 3166 ISO 3166:1988 (E/F) - Codes for the representation of! names of countries - The International Organization for! Standardization, 3rd edit

21、ion, 1988-08-15.!RFC 1327 Kille, S., Mapping between X.400 (1988) / ISO 10021 and! RFC 822, RFC 1327, May 1992.!RFC 1521 Borenstein, N., and N. Freed, MIME Part One: Mechanisms! for Specifying and Describing the Format of Internet! Message Bodies, RFC 1521, September 1993!RFC 2026 Bradner, S., The Internet Standards Process - Revision! 3, BCP 9, RFC 2026, Octo