Network Working Group G. Zorn
Request for Comments: 2484 Microsoft Corporation
Category: Standards Track January 1999
Updates: 2284, 1994, 1570
PPP LCP Internationalization Configuration Option
Status 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 by RFC2277 [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].
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
>= 7
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 in RFC2278 [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 in RFC1766 [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, RFC
1661, July 1994.
[2] Simpson, W., "PPP Challenge Handshake Authentication Protocol
(CHAP)", RFC1994, August 1996.
[3] Simpson, W., "PPP LCP Extensions", RFC1570, January 1994.
[4] Blunk, L. and J. Vollbrecht, "PPP Extensible Authentication
Protocol (EAP)", RFC2284, March 1998.
[5] Alvestrand, H., "IETF Policy on Character Sets and Languages",
BCP 18, RFC2277, January 1998.
[6] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC2119, March 1997.
[7] Reynolds, J. and J. Postel, "Assigned Numbers", STD 2, RFC1700,
October 1994. See also: http://www.iana.org/numbers.Html
[8] Alvestrand, H., "Tags for the Identification of Languages", RFC
1766, March 1995.
[9] Freed, N. and J. Postel, "IANA Charset Registration Procedures",
BCP 19, RFC2278, January 1998.
[10] Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC
2279, January 1998.
[11] Smith, R., Wright, F., Hastings, T., Zilles, S. and J.
Gyllenskog, "Printer MIB", RFC1759, 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.com
8. 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.com
9. Full Copyright Statement
Copyright (C) The Internet Society (1999). All Rights Reserved.
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The limited permissions granted above are perpetual and will not be
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