One document matched: draft-ietf-pppext-lcp-charset-00.txt

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
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or to cite them other than as ``work in progress''.

To  learn  the  current  status  of any Internet-Draft, please check the
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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].







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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...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




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   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.



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   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







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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]