Internet DRAFT - draft-brandner-enumservice-msg
draft-brandner-enumservice-msg
ENUM Working Group R. Brandner
Internet Draft Siemens
L. Conroy
Siemens
R. Stastny
OeFEG
Expires: August 2003 February 2003
Registration for enumservices of group messages
<draft-brandner-enumservice-msg-00.txt>
Status of this Memo
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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:'
Table of Contents
TBD
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 'sip:', 'h323:' and 'tel:' may be used), it is
necessary in 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.
2. Abbreviations
TBD
3. 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 7.
Intended Usage: COMMON
Author: Rudolf Brandner, Lawrence Conroy, Richard Stastny
(for author contact detail see section 10)
Any other information the author deems interesting:
None
4. 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 [ITU1] and [ITU2] - 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 7.
Intended Usage: COMMON
Author: Rudolf Brandner, Lawrence Conroy, Richard Stastny
(for author contact detail see section 10)
Any other information the author deems interesting:
None
5. MMS, EMS, SMS Service
5.1 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 EME standards.
These behaviors on the part of the client are purely optional, and
are NOT the subject of any protocol standardization.
5.2 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 System (SMS).
Security Considerations:
There are no specific security issues with this 'enumservice'.
However, the general considerations of section 7 apply.
Intended Usage: COMMON
Author: Rudolf Brandner, Lawrence Conroy, Richard Stastny
(for author contact detail see section 10)
Any other information the author deems interesting:
None
5.3 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
Extended Message System (EMS).
Security Considerations:
There are no specific security issues with this 'enumservice'.
However, the general considerations of section 7 apply.
Intended Usage: COMMON
Author: Rudolf Brandner, Lawrence Conroy, Richard Stastny
(for author contact detail see section 10)
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.
5.4 MMS Service Registration
Enumservice Name: "mms"
Type: "mms"
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 Message System (MMS).
Security Considerations:
There are no specific security issues with this 'enumservice'.
However, the general considerations of section 7 apply.
Intended Usage: COMMON
Author: Rudolf Brandner, Lawrence Conroy, Richard Stastny
(for author contact detail see section 10)
Note that an indication of MMS can be taken as implying that the
recipient is capable of receiving EMS or SMS messages at this
address.
6. Additional Information
Editor note: Is there any necessary additional information? TBD
7. 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 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.
8. References
1 Scott Bradner, RFC2026,
"The Internet Standards Process - Revision 3",
October 1996.
2 ITU-T T.4,
"Standardization of Group 3 facsimile terminals for
document transmission",
April 1999
3 ITU-T T.30,
"Procedures for document facsimile transmission in the
general switched telephone network",
April 1999
4 H. Schulzrinne, A. Vaha-Sipila,
"URIs for Telephone Calls",
draft-antti-RFC2806bis-07.txt,
Work in progress, December 2002
5 P. Faltstrom, M. Mealling,
"The E.164 to URI DDDS Application (ENUM)",
draft-ietf-enum-rfc2916bis-03.txt,
Work in progress, January 2003
6 ITU-T,
"The International Public Telecommunication Number Plan",
Recommendation E.164,
May 1997
7 P. Mockapetris, RFC1034,
"DOMAIN NAMES - CONCEPTS AND FACILITIES",
November 1987
8 ETSI TS 102 172,
"Minimum Requirements for Interoperability of
European ENUM Trials",
February 2003
9 M. Mealling, RFC 3401,
"Dynamic Delegation Discovery System (DDDS) Part One:
The Comprehensive DDDS",
October 2002
10 M. Mealling, RFC 3402,
"Dynamic Delegation Discovery System (DDDS) Part Two:
The Algorithm",
October 2002
11 M. Mealling, RFC 3403,
"Dynamic Delegation Discovery System (DDDS) Part Three:
The Domain Name System (DNS) Database",
October 2002
12 M. Mealling, RFC 3404,
"Dynamic Delegation Discovery System (DDDS) Part Four:
The Uniform Resource Identifiers (URI)",
October 2002
13 M. Mealling, RFC 3405,
"Dynamic Delegation Discovery System (DDDS) Part Five:
URI.ARPA Assignment Procedures",
October 2002
9. Author's Addresses
Rudolf Brandner
Siemens ICN
Hofmannstrasse 51
Munich
Germany
email: <mailto:rudolf.brandner@siemens.com>
voice: <tel:+49-89-72251003>
web: <http://www.siemens.com>
Lawrence Conroy
Siemens Roke Manor Research
Roke Manor
Romsey
U.K.
email: <mailto:lwc@roke.co.uk>
voice: <tel:+44-1794-833666>
Richard Stastny
OeFEG
Postbox 147
1103 Vienna
Austria
email: <mailto:richard.stastny@oefeg.at>
voice: <tel:+43-664-420-4100>
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