INTERNET-DRAFT                                            Edward Lewis
February 19, 2007                                         NeuStar, Inc.
Expires August 19, 2007

                     E.212 Parameters for the "tel" URI
                    draft-lewis-enum-teluri-e212-00.txt

By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware have
been or will be disclosed, and any of which he or she becomes aware will
be disclosed, in accordance with Section 6 of BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups. Note that other groups
may also distribute working documents 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."

The list of current Internet-Drafts can be accessed at
      http://www.ietf.org/1id-abstracts.html

The list of Internet-Draft Shadow Directories can be accessed at
      http://www.ietf.org/shadow.html

Abstract

Parameters are defined in the "tel" Uniform Resource Identifier (URI)
to carry ITU E.212-related information.

 Introduction

Three parameters are defined for the tel URI [RFC3966] to permit
storage of E.212 [ITUE212] data.  E.212 data has three components,
the Mobile Country Code (MCC), the Mobile Network Code (MNC), and the
Mobile Subscriber Identification Number (MSIN).  Collectively, these
form the Internation Mobile Subscriber Identity.

To store an IMSI, and therefore all three components, just one
parameter would be needed if not for concern over exposing the MSIN
in a public database like DNS.  There is a need to publically view the
MCC and MNC numbers though, so individual parameters are defined for
those values.

The parameter for the entire IMSI will be "imsi", the parameter for
the MCC will be "mcc" and the parameter for the MNC will be "mnc."
In the parlance of RFC 4694 [RFC4694], these parameters are suitable
for placement in static content.

 Terminology

The key words "MUST," "SHOULD," and "MAY" in this document are to be
interpreted as described in RFC 2119 [RFC2119].

 Formal Syntax

The following syntax specification uses the Augmented Backus-Naur
Form (ABNF) as described in RFC 4234 [RFC4234] and defines the three
parameters, imsi, mcc, and mnc by extending the "parameter" production
rule of the "tel" URI defined in [RFC3966].

parameter               = / imsi / mcc / mnc
imsi                    = ";imsi=" imsi-digits
mcc                     = ";mcc=" 3(DIGIT)
mnc                     = ";mnc=" (2(DIGIT) / 3(DIGIT))
imsi-digits             = (upto) 15(DIGIT) ; ed.note, fix this

 Normative Rules

If the imsi parameter is in use, all three values are expected to be
present.  Rules for the use of the parameter's value are contained
in the ITU document defining the IMSI.

The other two parameters, mcc and mnc are used in tandem to identify
the network serving the telephone number.

 Examples

For a telephone number +1-571-555-1000, served on a network whose MCC
is 330, MNC is 110 and MSIN is 123456789, the two "tel" URI's that
might appear with these parameters are:

     tel:+15715551000;imsi=330110123456789
     tel:+15715551000;mcc=330;mnc=110

 Security Considerations

The one concern raised in this document is the potential concern over
the privacy required for the MSIN that appears in the IMSI.  If the
IMSC parameter is used, the operator must understand the exposure that
may be had by the data.  The full IMSI ought to be restricted to
situations in which the exposure of the MSIN is acceptable.

To alleviate this concern, the MCC and MNC parameters are defined, these
are expected to be what appears in a pubic or otherwise widely (or
externally) distributed environment.

 IANA Considerations

This document requires no IANA actions.

 Internationalization Considerations

There are no internationalization considerations in these parameters.
All data are numeric.

 References

9.1 Normative

    [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

    [RFC3966] Schulzrinne, H., "The tel URI for Telephone Numbers", RFC
              3966, December 2004.

    [RFC4234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 4234, October 2005.

    [ITUE212] ITU-T Recommendation E.212, "The International
              Identification Plan for Mobile Terminals and Mobile
              Users, " May 2004.

9.2 Informative

(ed.note - do I need this, i.e., should it be mentioned in IANA consid.?)
    [TELREG]  Jennings, C. and V. Gurbani, "The Internet Assigned Numbers
              Authority (IANA) tel Uniform Resource Identifier (URI)
              Parameter Registry", Work in Progress, May 2006.

 Author's Address
    Edward Lewis
    NeuStar
    46000 Center Oak Plaza
    Sterling, VA
    20166, US

    Phone: +1-571-434-5468
    EMail: ed.lewis@neustar.biz


Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.

Copyright (C) The IETF Trust (2007).

This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors retain
all their rights.

This document and the information contained herein are provided
on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE
IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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.