Network Working Group G. Zorn Internet-Draft Microsoft Corporation Category: Standards Track March 1998 Updates: RFC 1570, RFC 1994, RFC 2284 <draft-ietf-pppext-lcp-charset-00.txt> PPP LCP Language and Character Set Configuration Options 1. Status of this Memo This document is an Internet-Draft. Internet-Drafts are working docu- ments of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working doc- uments as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as ``work in progress''. To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). The distribution of this memo is unlimited. It is filed as <draft-ietf- pppext-lcp-charset-00.txt> and expires September 15, 1998. Please send comments to the PPP Extensions Working Group mailing list (ietf- ppp@merit.edu) or to the author (glennz@microsoft.com). 2. 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 Link Control Protocol and Authentication Protocol packets may con- tain text which is intended to be human-readable [2, 3, 4]. This docu- ment defines LCP configuration options for the negotiation of character set and language usage, as required by RFC 2277 [5]. Zorn [Page 1]
INTERNET-DRAFT LCP Internationalization Options March 1998 3. 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 [5]. 4. Additional LCP Configuration Options The Configuration Option format and basic options are already defined for LCP [1]. Up-to-date values of the LCP Option Type field are specified in STD 2 [7]. This document concerns the following values: ?? Language-Tag ?? Charset-Name Both of the options described here MAY be negotiated independently in each direction. Only one instance of either option SHOULD be sent by an implementation, representing its preferred language or charset. If either the Langage-Tag or the Charset-Name option is rejected by the peer, the appropriate default language or charset MUST be used. Peers SHOULD NOT NAK either of these options; if either option is NAK'd, the peer SHOULD reject the option. 4.1. Language-Tag Description This Configuration Option provides a method for an implementation to indicate to the peer the language in which human-readable mes- sages it sends should be composed. A summary of the Language-Tag Option format is shown below. The fields are transmitted from left to right. 0 1 2 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Tag... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Zorn [Page 2]
INTERNET-DRAFT LCP Internationalization Options March 1998 Type ?? Length >= 3 Tag The Tag field is an ASCII string which contains a language tag, as defined in RFC 1766 [8]. The default Tag value is "i-default" [8]. 4.2. Charset-Name Description This Configuration Option provides a method for an implementation to indicate to the peer the charset in which human-readable messages it sends should be represented. A summary of the Charset-Name Option format is shown below. The fields are transmitted from left to right. 0 1 2 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Name... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type ?? Length >= 3 Tag The Name field is an ASCII string which contains a charset name. Zorn [Page 3]
INTERNET-DRAFT LCP Internationalization Options March 1998 This name MUST be one of the set of charsets listed in the IANA charset registry [7]. The charset registration procedure is described in RFC 2278 [9]. The default charset value is UTF-8 [10]. 5. Security Considerations It is possible that an attacker might manipulate the options in such a way that displayable messages would be unintelligible to the reader. 6. References [1] Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51, RFC 1661, 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 Vollbrecht, J., "PPP Extensible Authentication Proto- col (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 Postel, J., "Assigned Numbers", STD 2, RFC 1700, October 1994 [8] Alvestrand, H., "Tags for the Identification of Languages", RFC 1766, March 1995 [9] Freed, N. and Postel, J., "IANA Charset Registration Procedures", BCP 9, RFC 2026, October 1996 [10] Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC 2279, January 1998 Zorn [Page 4]
INTERNET-DRAFT LCP Internationalization Options March 1998 7. Chair's Address The PPP Extensions Working Group can be contacted via the current chair: Karl Fox Ascend Communications 3518 Riverside Drive Suite 101 Columbus, OH 43221 Phone: +1 614 326 6841 Email: karl@ascend.com 8. Author's Address Questions about this memo can also be directed to: Glen Zorn Microsoft Corporation One Microsoft Way Redmond, Washington 98052 Phone: +1 425 703 1559 FAX: +1 425 936 7329 EMail: glennz@microsoft.com 9. Expiration Date This memo is filed as <draft-ietf-pppext-lcp-charset-00.txt> and expires on September 15, 1998. Zorn [Page 5]
