Internet DRAFT - draft-brandner-enumservice-vovi
draft-brandner-enumservice-vovi
ENUM Working Group R. Brandner
Internet Draft Siemens
L. Conroy
Siemens Roke Manor Research
R. Stastny
OeFEG
Expires: January 2005 July 2004
IANA Registration for enumservices voice and video
<draft-brandner-enumservice-vovi-02.txt>
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Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This document registers the ENUMservices "voice" and "video" (each of
which has a defined sub-type "tel"), as per the IANA registration
process defined in the ENUM specification RFC3761[4]. These services
are be used to indicate that the contact held in the generated URI
can be used to initiate an interactive voice or video/audio call
respectively.
Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [3].
1. Introduction
RFC3761 [4] (ENUM) describes a machanism to populate communication
contacts within DNS [5] associated with an E.164 [6] number, using
NAPTRs [7] that hold the DDDS [8][9] Application identifier "E2U".
It defines a framework whereby the person controlling its population
may indicate the kind of communication that can result from using
the contact. This indication is called an ENUMservice, and there may
be more than one ENUMservice associated with a single NAPTR, where
the contact may be used to initiate more than one kind of
communication.
ENUMservices have a type and subtype. This latter is optional, as it
may be implicit in the service type. The type defines the kind of
communication session that can be initiated using the contact
indicated by the URI generated by the enclosing NAPTR. The sub-type
defines the subsystem that is to be used to initiate the
communication session. Note that the sub-type definition includes
the URI style that is to be used. Both the type and subtype (where
present) must be supported for the NAPTR to be used by a potential
correspondent.
Whilst the protocol elements that make up ENUM are defined in the
above documents and in this one, further examples of the use to
which these may be put are given in other documents, for example in
ETSI TS 102 172 [11].
There are a number of DDDS Applications in addition to ENUM (for
example, see [12] and [13]). However, an ENUMservice indication
operates only within the context of the "E2U" (ENUM) DDDS
Application.
That context is specified in RFC3761, and requires a a standards
track or experimental RFC to define the expectations for the
ENUMservice, to be referred to in the IANA registry of ENUMservices.
This document is the defining document for the ENUMservices "voice"
and "video".
2. ENUMservice for Interactive Voice
ENUMservice Type:
"Voice"
The kind of communication indicated by this ENUMservice is
"Interactive Voice". From a protocol perspective, this
communication is expected to involve bidirectional media streams
carrying audio data.
A client may imply that the person controlling population of a
NAPTR holding this ENUMservice indicates their capability to engage
in an interactive voice session when contacted using the URI
generated by this NAPTR.
2.1. Defined Sub-types for Interactive Voice
2.1.1 ENUMservice "Voice" Sub-type "Tel"
Sub-type:
"tel"
Generated URI scheme:
"tel:" (defined in RFC2806 [10])
This sub-type indicates that the person responsible for the NAPTR
is accessible via the PSTN (Public Switched Telephone Network) or
PLMN (Public Land Mobile Network) using the value of the generated
URI.
The kind of subsystem required to initiate a Voice ENUMservice with
this sub-type is a "Dialler". This is a subsystem that either
provides a local connection to the PSTN or PLMN, or that provides
an indirect connection to those networks. The subsystem will use
the telephone number held in the generated URI to place a voice
call. The voice call is placed to a network that uses E.164 numbers
to route calls to an appropriate destination.
Note that the PLMN connection may be indirect. The end user
receiving this NAPTR may have a relationship with a Communications
Service Provider that accepts call initiation requests from that
subsystem using an IP-based protocol such as SIP or H.323, and
places the call to the PSTN using a remote gateway service. In this
case the Provider may either accept requests using "tel:" URIs or
has a defined mechanism to convert "tel:" URI values into a
"protocol-native" form.
The "tel:" URI value SHOULD be fully qualified (using the "global
phone number" form of RFC2806 [10]). A "local phone number" [10]
SHOULD NOT be used unless the controller of the zone in which the
NAPTR appears is sure that it can be distinguished unambiguously by
all clients that can access the resouce record and that a call from
their network access points can be routed to that destination.
2.1.1.2 Security Considerations
See main security considerations section of this document.
2.1.1.3. Intended Usage of ENUMservice Voice
COMMON
2.1.1.4. Authors
Rudolf Brandner, Lawrence Conroy, Richard Stastny
(for author contact detail see section 9)
2.1.1.5. Other Information Author Deems Interesting
NONE
3. ENUMservice for Interactive Video
ENUMservice Type:
"video"
The kind of communication indicated by this ENUMservice is
"Interactive Video and Voice". From a protocol perspective, this
communication is expected to involve bidirectional media streams
carrying video and audio data.
A client may imply that the person controlling population of a
NAPTR holding this ENUMservice indicates their capability to engage
in an interactive video and voice session when contacted using the
URI generated by this NAPTR.
3.1. Defined Sub-types for Interactive Video
3.1.1. ENUMservice "Video" sub-type "Tel"
Sub-type:
"tel"
Generated URI scheme:
"tel:" (defined in RFC2806 [10])
There are existing Video/Voice services provided over the telephone
network, and this ENUMservice indicates that the destination has
such a service. Specifically, this sub-type indicates that the
person responsible for the NAPTR is accessible via the PSTN (Public
Switched Telephone Network) or PLMN (Public Land Mobile Network)
using the value of the generated URI.
The kind of subsystem required to initiate a Voice ENUMservice with
this sub-type is a "Dialler". This is a subsystem that either
provides a local connection to the PSTN or PLMN, or that provides
an indirect connection to those networks. The subsystem will use
the telephone number held in the generated URI to place a call via
the PSTN/PLMN network connection. See also section 2.1.1 above.
3.1.1.2 Security Considerations
See main security considerations section of this document.
3.1.1.3. Intended Usage of ENUMservice Voice
COMMON
3.1.1.4. Authors
Rudolf Brandner, Lawrence Conroy, Richard Stastny
(for author contact detail see section 9)
3.1.1.5. Other Information Author Deems Interesting
NONE
4. Additional Information
NONE
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 voice or video call via the PSTN or 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 place a call to this destination
number, but they SHOULD be shown the destination number so that they
can make this decision
Where voice or video terminals are configured to accept incoming
calls, there SHOULD be an indication presented to the user that an
incoming call is being offered. Particularly with some video
systems, the terminal may be configured to "auto-accept" the call.
In this case there MUST be an obvious indication presented to the
called user that this has been done.
Systems configured to auto-accept audio/video calls that are sent to
a number published in a global public directory may be used by
unexpected individuals to check for the presence or otherwise of
people with a view to stealing property or other unwelcome acts.
Whilst "security through obscurity" may have seemed acceptable when
the access address was known to only a few, publication within ENUM
removes the obscurity, so leaving (for example) a "WebCam" switched
on after such publication is even less wise than in other
situations.
In addition to the specific security considerations given above, all
security considerations given in RFC3761 apply.
6. IANA Considerations
This document requests that IANA adds entries to the Registry of
ENUMservices set up as defined in the framework of RFC3761 for:
- ENUMservice type "voice" with sub-type "tel", and for
- ENUMservice type "video" with sub-type "tel".
This document defines these ENUMservices and should be referred to
in the Registry entries as their specification.
7. Normative References:
[1] Bradner, S., "Intellectual Property Rights in IETF Technology",
BCP 78, RFC3667, February 2004
[2] Bradner, S., "IETF Rights in Contributions", BCP 79, RFC3668,
February 2004
[3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997
[4] Faltstrom, P. and Mealling M., "The E.164 to Uniform Resource
Identifiers (URI) Dynamic Delegation Discovery System (DDDS)
Application (ENUM)", RFC 3761, April 2004.
[5] Mockapetris, P., "Domain Names - Concepts and Facilities", STD
13, RFC 1034, November 1987
[6] ITU-T, "The International Public Telecommunication Number Plan",
Recommendation E.164, May 1997
[7] Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part
Three: The Domain Name System (DNS) Database", RFC 3403, October
2002.
[8] M. Mealling, RFC 3401,
"Dynamic Delegation Discovery System (DDDS) Part One:
The Comprehensive DDDS", October 2002
[9] M. Mealling, RFC 3402,
"Dynamic Delegation Discovery System (DDDS) Part Two:
The Algorithm", October 2002
[10] A. Vaha-Sipila, RFC 2806, "URLs for Telephone Calls", April 2000
8. Informative References:
[11] ETSI TS 102 172,
"Minimum Requirements for Interoperability of European ENUM
Trials", July 2004
[12] M. Mealling, RFC 3404,
"Dynamic Delegation Discovery System (DDDS) Part Four:
The Uniform Resource Identifiers (URI) Resolution
Application", October 2002
[13] M. Mealling, RFC 3405,
"Dynamic Delegation Discovery System (DDDS) Part Five:
URI.ARPA Assignment Procedures", October 2002
9. Authors' 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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