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 Status of this Memo By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, or will be disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. 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 a "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 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: voice: web: Lawrence Conroy Siemens Roke Manor Research Roke Manor Romsey U.K. email: voice: Richard Stastny OeFEG Postbox 147 1103 Vienna Austria email: voice: 10. 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