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Versions: 00 02 03 04 05 06 RFC 2484

Network Working Group                                            G. Zorn
Internet-Draft                                     Microsoft Corporation
Category: Standards Track                                    August 1998
Updates: RFC 1570, RFC 1994, RFC 2284

        PPP LCP Language and Character Set Configuration Option

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-02.txt>  and  expires  February 9, 1999.  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  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 by RFC 2277 [5].

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INTERNET-DRAFT       LCP Internationalization Option        August 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 Option

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 value:

   ??  Charset-Language

The Charset-Language option described here MAY  be  negotiated  indepen-
dently in each direction.

Only  one  instance  of this option SHOULD be sent by an implementation,
representing its preferred language and charset.

If Charset-Language option is rejected  by  the  peer,  the  appropriate
default language and charset MUST be used.

Peers  SHOULD  NOT  NAK  this  option;  if the option is NAK'd, the peer
SHOULD reject the option.

4.1.  Charset-Language


      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  the
      language should be represented.

   A  summary of the Charset-Language 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)        |           Tag...

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INTERNET-DRAFT       LCP Internationalization Option        August 1998





      >= 7


      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 in RFC 2278 [9].

      The default charset value is UTF-8 [10].  The  MIBenum  value  for
      the UTF-8 charset is 106.


         The Tag field is an ASCII string which contains a language tag,
         as defined in RFC 1766 [8].

         Language tags are in principle case-insensitive; however, since
         a  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].

5.  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

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INTERNET-DRAFT       LCP Internationalization Option        August 1998

[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 19, RFC 2278, January 1998

[10] Yergeau, F., "UTF-8, a transformation format  of  ISO  10646",  RFC
     2279, January 1998

[11] Smith, R., et al., "Printer MIB", RFC 1759, March 1995

6.  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.

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:

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INTERNET-DRAFT       LCP Internationalization Option        August 1998

   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-02.txt> and expires
on February 9, 1999.

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