ENUM                                                         R. Brandner
Internet-Draft                                                Siemens AG
Expires: December 14, 2003                                     L. Conroy
                                             Siemens Roke Manor Research
                                                              R. Stastny
                                                                   Oefeg
                                                           June 15, 2003


            Registration for enumservices of group messages
                      <draft-ietf-enum-msg-00.txt>

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on December 14, 2003.

Copyright Notice

   Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

   This document registers a group of 'enumservices' [5] to be used to
   indicate that the associated resources are capable of receiving
   discrete messages.

   Specifically, the "enumservices" registered with this document are
   'email', 'fax', 'sms', 'ems' and 'mms' using the URI schemes
   'mailto:' and 'tel:'.





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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  E-mail Service Registration  . . . . . . . . . . . . . . . . .  5
   3.  Fax Service Registration . . . . . . . . . . . . . . . . . . .  7
   4.  MMS, EMS, SMS Service  . . . . . . . . . . . . . . . . . . . .  8
   4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  8
   4.2 SMS Service Registration . . . . . . . . . . . . . . . . . . .  8
   4.3 EMS Service Registration . . . . . . . . . . . . . . . . . . .  9
   4.4 MMS Service Registration . . . . . . . . . . . . . . . . . . .  9
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   6.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
       References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 15
       Intellectual Property and Copyright Statements . . . . . . . . 16




































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1. Introduction

   ENUM (E.164 Number Mapping, RFC2916bis [5]) is a system that
   transforms E.164 numbers [6] into domain names and then uses DNS
   (Domain Name Service, RFC1034 [7]) services like delegation through
   NS records and NAPTR records to look up what services are available
   for a specific domain name.

   This document registers 'enumservices' according to the guidelines
   given in RFC2916bis to be used for provisioning in the services field
   of a NAPTR [10] resource record to indicate what class of
   functionality a given end point offers. The registration is defined
   within the DDDS (Dynamic Delegation Discovery System
   [9][10][11][12][13]) hierarchy, for use with the "E2U" DDDS
   Application defined in RFC2916bis.

   The following 'enumservices' are registered with this document:
   'email', 'fax', 'sms', 'ems' and 'mms'. These share a common feature
   in that they each indicate that the functionality of the given end
   points and the associated resources are capable of receiving discrete
   messages, albeit of different types.

   According to RFC2619bis, the 'enumservice' registered must be able to
   function as a selection mechanism when choosing one NAPTR resource
   record from another. That means that the registration MUST specify
   what is expected when using that very NAPTR record, and the URI
   scheme which is the outcome of the use of it.

   Therefore an 'enumservice' acts as a hint, indicating the kind of
   service with which the URI constructed using the regexp field is
   associated. There can be more than one 'enumservice' included within
   a single NAPTR; this indicates that there is more than one service
   that can be achieved using the associated URI scheme.

   The common thread with this set of definitions is that they reflect
   the kind of service that the end user will hope to achieve with the
   communication using the associated URI.

   The services specified here are intended NOT to specify the protocol
   or even method of connection that MUST be used to achieve each
   service. Instead they define the kind of interactive behavior that an
   end user will expect, leaving the end system to decide (based on
   policies outside the remit of this specification) how to execute the
   service.

   Since the same URI scheme may be used for different services (e.g.
   'tel:'), and the same kind of service may use different URI schemes
   (e.g. for VoIP 'h323:' and 'tel:' may be used), it is necessary in



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   some cases to specify the service and the URI scheme used.

   The service parameters defined in RFC2916bis allow therefore a 'type'
   and a 'subtype' to be specified. Within this set of specifications
   the convention is assumed that the 'type' (being the more generic
   term) is defining the service and the 'subtype' is defining the URI
   scheme.

   Although currently only one URI scheme is associated with a given
   service, it should be considered that an additional URI scheme to be
   used with this service may be added later. Thus the subtype is needed
   to identify the specific 'enumservice' intended.







































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2. E-mail Service Registration

   Enumservice Name: "email"

   Type: "email"

   Subtype: "mailto"

   URI Scheme: 'mailto:'

   Functional Specification:

   This enumservice indicates that the remote resource can be addressed
   by the associated URI scheme in order to send an email.

   Security Considerations:

   An e-mail address is a canonical address by which a user is known.
   Placing this address in ENUM is comparable to placing a SIP or H.323
   address in the DNS.

   DNS does not make any policy decisions about the records that is
   shares with an inquirer. All DNS records must be assumed to be
   available to all inquirers at all times. The information provided
   within an ENUM NAPTR resource record must therefore be considered to
   be open to the public, which is a cause for some privacy
   considerations.

   Therefore ENUM Subscribers should be made aware of this risk. Since
   it is within the responsibility of the ENUM Subscriber which data is
   entered in ENUM, it is within the ENUM Subscribers control if he
   enters e-mail addresses:

   1.  allowing inference of private data e.g. his first and last name

   2.  at all

   It should also be considered that it is the purpose of public
   communication identifiers to be publicly known. To reduce spam and
   other unwanted communication other means should be made available.

   See also Section 5.

   Intended Usage: COMMON

   Author:

   Rudolf Brandner, Lawrence Conroy, Richard Stastny (for author contact



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   detail see Authors' Addresses section)

   Any other information the author deems interesting:

   None














































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3. Fax Service Registration

   Enumservice Name: "fax"

   Type: "fax"

   Subtype: "tel"

   URI Scheme: 'tel:'

   Functional Specification:

   This enumservice indicates that the resource identified by the
   associated URI scheme is capable of being contacted to provide a
   communication session during which facsimile documents can be sent.

   A client selecting this NAPTR will have support for generating and
   sending facsimile documents to the recipient using the PSTN session
   and transfer protocols specified in [2] and [3] - in short, they will
   have a fax program with a local or shared PSTN access over which they
   can send faxes.

   Security Considerations:

   An fax number as any other phone number may give not so much privacy
   away then a name in the format user@host (e.g. an email or sip
   address), but there is still the risk of unwanted messages. Therefore
   in principle the same applies as stated in the security consideration
   for e-mail.

   See also Section 5.

   Intended Usage: COMMON

   Author:

   Rudolf Brandner, Lawrence Conroy, Richard Stastny (for author contact
   detail see Authors' Addresses section)

   Any other information the author deems interesting:

   None









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4. MMS, EMS, SMS Service

4.1 Introduction

   An ENUM NAPTR indicates ability on the part of the Subscriber to
   receive specified communication service (or services) provided via
   the contact address (shown in the generated URI).

   In the case of MMS, EMS, and SMS services, the capability of these
   services is a nested superset; thus a service supporting MMS can
   support also delivery of EMS or SMS messages to a recipient, whilst a
   service supporting EMS can also deliver SMS messages.

   Thus, if a client is capable only of generating and sending an SMS
   message, they MAY choose to consider also NAPTRs indicating support
   for EMS and MMS services as well as SMS, as these services will be
   able to deliver an SMS message to the recipient address.

   Conversely, a client capable of sending MMS messages may choose to
   consider also NAPTRs indicating support for EMS or SMS messages,
   "downgrading" their User Interface to allow only generation of
   messages that conform to SMS or EMS standards.

   These behaviours on the part of the client are purely optional, and
   are NOT the subject of any protocol standardization.

4.2 SMS Service Registration

   Enumservice Name: "sms"

   Type: "sms"

   Subtype: "tel"

   URI Scheme: 'tel:'

   Functional Specification:

   This enumservice indicates that the resource identified by the
   associated URI scheme is capable of receiving a message using the
   Short Message Service (SMS) [14].

   Security Considerations:

   There are no specific security issues with this 'enumservice'.
   However, the general considerations of Section 5 apply.

   Intended Usage: COMMON



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   Author:

   Rudolf Brandner, Lawrence Conroy, Richard Stastny (for author contact
   detail see Authors' Addresses section)

   Any other information the author deems interesting:

   None

4.3 EMS Service Registration

   Enumservice Name: "ems"

   Type: "ems"

   Subtype: "tel"

   URI Scheme: 'tel:'

   Functional Specification:

   This enumservice indicates that the resource identified by the
   associated URI scheme is capable of receiving a message using the
   Enhanced Message Service (EMS) [14].

   Security Considerations:

   There are no specific security issues with this 'enumservice'.
   However, the general considerations of Section 5 apply.

   Intended Usage: COMMON

   Author:

   Rudolf Brandner, Lawrence Conroy, Richard Stastny (for author contact
   detail see Authors' Addresses section)

   Any other information the author deems interesting:

   Note that an indication of EMS can be taken as implying that the
   recipient is capable of receiving SMS messages at this address as
   well.

4.4 MMS Service Registration

   Enumservice Name: "mms"

   Type: "mms"



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   Subtype: "tel"

   URI Scheme: 'tel:'

   Functional Specification:

   This enumservice indicates that the resource identified by the
   associated URI scheme is capable of receiving a message using the
   Multimedia Messaging Service (MMS) [15].

   Security Considerations:

   There are no specific security issues with this 'enumservice'.
   However, the general considerations of Section 5 apply.

   Intended Usage: COMMON

   Author:

   Rudolf Brandner, Lawrence Conroy, Richard Stastny (for author contact
   detail see Authors' Addresses section)

   Any other information the author deems interesting:

   Note that MMS can be used as an alternative to deliver an SMS RP-DATA
   RPDU if, for example, the SMS bearer is not supported. If an entry
   includes this enumservice, then in effect this can be taken as
   implying that the recipient is capable of receiving EMS or SMS
   messages at this address. Such choices on the end system design do
   have a small caveat; whilst in practise all terminals supporting MMS
   today support SMS as well, it might not necessarily be the case in
   the future. Also, MMS is under current development and so there may,
   in the future, be other enumservices with type 'mms'.


















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5. Security Considerations

   DNS, as used by ENUM, is a global, distributed database. Thus any
   information stored there is visible to anyone anonymously. Whilst
   this is not qualitatively different from publication in a Telephone
   Directory, it does open the data subject to having "their"
   information collected automatically without any indication that this
   has been done or by whom.

   Such data harvesting by third parties is often used to generate lists
   of targets for unrequested information; in short, they are used to
   address "spam". Anyone who uses a Web-archived mailing list is aware
   that the volume of "spam" email they are sent increases when they
   post to the mailing list; publication of a telephone number in ENUM
   is no different, and may be used to send "junk faxes" or "junk SMS"
   for example.

   Many mailing list users have more than one email address and use
   "sacrificial" email accounts when posting to such lists to help
   filter out unrequested emails sent to them. This is not so easy with
   published telephone numbers; the PSTN E.164 number assignment process
   is much more involved and usually a single E.164 number (or a fixed
   range of numbers) is associated with each PSTN access. Thus providing
   a "sacrificial" phone number in any publication is not possible.

   Due to the implications of publishing data on a globally accessible
   database, as a principle the data subject MUST give their explicit
   informed consent to data being published in ENUM.

   In addition, they should be made aware that, due to storage of such
   data during harvesting by third parties, removal of the data from
   publication will not remove any copies that have been taken; in
   effect, any publication may be permanent.

   However, regulations in many regions will require that the data
   subject can at any time request that the data is removed from
   publication, and that their consent for its publication is explicitly
   confirmed at regular intervals.

   When placing a fax call via the PSTN or a sending a message via the
   Public Land Mobile Network, the sender may be charged for this
   action. In both kinds of network, calling or messaging to some
   numbers is more expensive than sending to others; both networks have
   "premium rate" services that can charge considerably more than a
   "normal" call or message destination. As such, it is important that
   the end user be asked to confirm sending the message, and that the
   destination number be presented to them. It is the originating user's
   choice on whether or not to send a message to this destination



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   number, but they SHOULD be shown the destination number so that they
   can make this decision.

   In addition to the specific security considerations given above, all
   security considerations given in RFC2916bis apply.














































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6. Acknowledgements

   Many thanks to Ville Warsta for his close reading of the draft and
   extracting the right references.















































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References

   [1]   Bradner, S., "The Internet Standards Process -- Revision 3",
         RFC 2026, BCP 9, October 1996.

   [2]   ITU-T, "Standardization of Group 3 facsimile terminals for
         document transmission", T.4 , April 1999.

   [3]   ITU-T, "Procedures for document facsimile transmission in the
         general switched telephone network", T.30 , April 1999.

   [4]   Schulzrinne, H. and A. Vaha-Sipila, "URIs for Telephone Calls",
         draft-antti-RFC2806bis-08.txt , February 2003.

   [5]   Faltstrom, P. and M. Mealling, "The E.164 to URI DDDS
         Application (ENUM)", draft-ietf-enum-rfc2916bis-06.txt , May
         2003.

   [6]   ITU-T, "The International Public Telecommunication Number
         Plan", Recommendation E.164 , May 1997.

   [7]   Mockapetris, P., "DOMAIN NAMES - CONCEPTS AND FACILITIES", RFC
         1034, November 1987.

   [8]   ETSI, "Minimum Requirements for Interoperability of European
         ENUM Trials", ETSI TS  102 172, February 2003.

   [9]   Mealling, M., "Dynamic Delegation Discovery System (DDDS)  Part
         One: The Comprehensive DDDS", RFC 3401, October 2002.

   [10]  Mealling, M., "Dynamic Delegation Discovery System (DDDS)  Part
         Two: The Algorithm", RFC 3402, October 2002.

   [11]  Mealling, M., "Dynamic Delegation Discovery System (DDDS)  Part
         Three: The Domain Name System (DNS) Database", RFC 3403,
         October 2002.

   [12]  Mealling, M., "Dynamic Delegation Discovery System (DDDS)  Part
         Four: The Uniform Resource Identifiers (URI)", RFC 3404,
         October 2002.

   [13]  Mealling, M., "Dynamic Delegation Discovery System (DDDS)  Part
         Five: URI.ARPA Assignment Procedures", RFC 3405, October 2002.

   [14]  3GPP, "Technical realization of the Short Message Service
         (SMS);  (Release5)", TS 23.040 .

   [15]  3GPP, "Multimedia Messaging Service (MMS); Functional



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         description;  Stage 2 (Release 5)", TS 23.140 .


Authors' Addresses

   Rudolf Brandner
   Siemens AG
   Hofmannstr. 51
   81359 Munich
   Germany

   Phone: +49-89-722-51003
   EMail: rudolf.brandner@siemens.com


   Lawrence Conroy
   Siemens Roke Manor Research
   Roke Manor
   Romsey
   United Kingdom

   Phone: +44-1794-833666
   EMail: lwc@roke.co.uk


   Richard Stastny
   Oefeg
   Postbox 147
   1103 Vienna
   Austria

   Phone: +43-664-420-4100
   EMail: Richard.stastny@oefeg.at


















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Intellectual Property Statement

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   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.











































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