Movatterモバイル変換

Network Working Group                                            G. ZornRequest for Comments: 2484                         Microsoft CorporationCategory: Standards Track                                   January 1999Updates:2284,1994,1570           PPP LCP Internationalization Configuration OptionStatus of this Memo   This document specifies an Internet standards track protocol for the   Internet community, and requests discussion and suggestions for   improvements.  Please refer to the current edition of the "Internet   Official Protocol Standards" (STD 1) for the standardization state   and status of this protocol.  Distribution of this memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (1999).  All Rights Reserved.1.  Abstract   The Point-to-Point Protocol (PPP) [1] provides a standard method for   transporting multi-protocol datagrams over point-to-point links.  PPP   also defines an extensible Link Control Protocol (LCP), which allows   negotiation of an Authentication Protocol for authenticating its peer   before allowing Network Layer protocols to transmit over the link.   Both LCP and Authentication Protocol packets may contain text which   is intended to be human-readable [2,3,4].  This document defines an   LCP configuration option for the negotiation of character set and   language usage, as required byRFC 2277 [5].2.  Specification of Requirements   In this document, the key words "MAY", "MUST, "MUST NOT", "optional",   "recommended", "SHOULD", and "SHOULD NOT" are to be interpreted as   described in [6].3.  Additional LCP Configuration Option   The Configuration Option format and basic options are already defined   for LCP [1].Zorn                        Standards Track                     [Page 1]

RFC 2484            LCP Internationalization Option         January 1999   Up-to-date values of the LCP Option Type field are specified in STD 2   [7].  This document concerns the following value:      28  Internationalization   The Internationalization option described here MAY be negotiated   independently in each direction.   Only one instance of this option SHOULD be sent by an implementation,   representing its preferred language and charset.   If Internationalization option is rejected by the peer, the default   language and charset MUST be used to construct all human-readable   messages sent to the peer.4.1.  Internationalization   Description      This Configuration Option provides a method for an implementation      to indicate to the peer both the language in which human-readable      messages it sends should be composed and the charset in which that      language should be represented.   A summary of the Internationalization option format is shown below.   The fields are transmitted from left to right.    0                   1                   2                   3    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   |     Type      |    Length     |          MIBenum   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+             MIBenum (cont)        |        Language-Tag...   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   Type      28   Length      >= 7Zorn                        Standards Track                     [Page 2]

RFC 2484            LCP Internationalization Option         January 1999   MIBenum      The MIBenum field is four octets in length.  It contains a unique      integer value identifying a charset [5,11].      This value MUST represent one of the set of charsets listed in the      IANA charset registry [7].      The charset registration procedure is described inRFC 2278 [9].      The default charset value is UTF-8 [10].  The MIBenum value for      the UTF-8 charset is 106.   Language-Tag      The Language-Tag field is an ASCII string which contains a      language tag, as defined inRFC 1766 [8].      Language tags are in principle case-insensitive; however, since      the capitalization of a tag does not carry any meaning,      implementations SHOULD send only lower-case Tag fields.      The default Tag value is "i-default" [8].4.  References   [1]  Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51,RFC1661, July 1994.   [2]  Simpson, W., "PPP Challenge Handshake Authentication Protocol        (CHAP)",RFC 1994, August 1996.   [3]  Simpson, W., "PPP LCP Extensions",RFC 1570, January 1994.   [4]  Blunk, L. and J. Vollbrecht, "PPP Extensible Authentication        Protocol (EAP)",RFC 2284, March 1998.   [5]  Alvestrand, H., "IETF Policy on Character Sets and Languages",BCP 18,RFC 2277, January 1998.   [6]  Bradner, S., "Key words for use in RFCs to Indicate Requirement        Levels",BCP 14,RFC 2119, March 1997.   [7]  Reynolds, J. and J. Postel, "Assigned Numbers", STD 2,RFC 1700,        October 1994.  See also:http://www.iana.org/numbers.html   [8]  Alvestrand, H., "Tags for the Identification of Languages",RFC1766, March 1995.Zorn                        Standards Track                     [Page 3]

RFC 2484            LCP Internationalization Option         January 1999   [9]  Freed, N. and J. Postel, "IANA Charset Registration Procedures",BCP 19,RFC 2278, January 1998.   [10] Yergeau, F., "UTF-8, a transformation format of ISO 10646",RFC2279, January 1998.   [11] Smith, R., Wright, F., Hastings, T., Zilles, S. and J.        Gyllenskog, "Printer MIB",RFC 1759, March 1995.5.  Security Considerations   It is possible that an attacker might manipulate the option in such a   way that displayable messages would be unintelligible to the reader.6.  Acknowledgements   Thanks to Craig Fox (fox@cisco.com), James Carlson   (carlson@ironbridgenetworks.com), Harald Alvestrand   (Harald.Alvestrand@maxware.no), Kevin Smith (kevin@ascend.com), Karl   Fox (karl@ascend.com), Thomas Narten (narten@raleigh.ibm.com) and   Narendra Gidwani (nareng@microsoft.com) for helpful suggestions and   feedback.7.  Chair's Address   Karl Fox   Ascend Communications   3518 Riverside Drive   Suite 101   Columbus, OH 43221   Phone: +1 614 326 6841   EMail: karl@ascend.com8.  Author's Address   Glen Zorn   Microsoft Corporation   One Microsoft Way   Redmond, Washington 98052   Phone: +1 425 703 1559   Fax:   +1 425 936 7329   EMail: glennz@microsoft.comZorn                        Standards Track                     [Page 4]

RFC 2484            LCP Internationalization Option         January 19999.  Full Copyright Statement   Copyright (C) The Internet Society (1999).  All Rights Reserved.   This document and translations of it may be copied and furnished to   others, and derivative works that comment on or otherwise explain it   or assist in its implementation may be prepared, copied, published   and distributed, in whole or in part, without restriction of any   kind, provided that the above copyright notice and this paragraph are   included on all such copies and derivative works.  However, this   document itself may not be modified in any way, such as by removing   the copyright notice or references to the Internet Society or other   Internet organizations, except as needed for the purpose of   developing Internet standards in which case the procedures for   copyrights defined in the Internet Standards process must be   followed, or as required to translate it into languages other than   English.   The limited permissions granted above are perpetual and will not be   revoked by the Internet Society or its successors or assigns.   This document and the information contained herein is provided on an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Zorn                        Standards Track                     [Page 5]