ENUM Working Group J. Livingood Internet-Draft Comcast Cable Communications Expires: May 16, 2008 P. Pfautz Intended Status: Proposed Standard AT&T R. Stastny Oefeg November 13, 2007 The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application for Infrastructure ENUM draft-ietf-enum-infrastructure-07 Status of this Memo 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/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on May 16, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document defines the use case for Infrastructure ENUM and proposes its implementation as a parallel namespace to "e164.arpa" as defined in RFC3761, as the long-term solution to the problem of Livingood, et. al. Expires May 16, 2008 [Page 1] Internet-Draft Infrastructure ENUM November 2007 allowing carriers to provision DNS records for telephone numbers independently of those provisioned by end users (number assignees). Table of Contents 1. Terminology....................................................2 2. Introduction...................................................2 3. Zone Apex for Infrastructure ENUM..............................3 4. IANA Considerations............................................3 5. Security and Privacy Considerations............................3 6. Acknowledgements...............................................4 7. References.....................................................4 7.1 Normative References.......................................4 7.2 Informative References.....................................4 Authors' Addresses................................................4 Intellectual Property and Copyright Statements....................5 1. Terminology 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 BCP 14, RFC-2119 [5]. 2. Introduction ENUM (E.164 Number Mapping, RFC 3761 [1]) is a system that transforms E.164 numbers [2] into domain names and then uses the DNS (Domain Name Service) [3] to discover NAPTR records that specify what services are available for a specific domain name. ENUM as originally defined was based on the end-user opt-in principle. While this has great potential to foster new services and end-user choice in the long-term, the current requirements for IP- based interconnection of Voice over IP (VoIP) domains require the provisioning of large numbers of allocated or served (hosted) numbers of a participating service provider, without the need for individual users to opt-in or not and so that service providers can provision their own ENUM information that is separate, distinct, and likely to be different from what and end-user may provision. This is particularly important if Infrastructure ENUM is used for number portability applications, for example, which an end-user would be unlikely to be interested in provisioning but which a service provider would likely find essential. In addition, while it is possible that service providers could mandate that their users opt-in into e164.arpa through end-user Livingood, et. al. Expires May 16, 2008 [Page 2] Internet-Draft Infrastructure ENUM November 2007 contract terms and conditions, there are substantial downsides to such an approach. Thus, for all these reasons and many others, ENUM for end-user provisioning is ill-suited for use by service providers for the interconnection of VoIP domains. As VoIP evolves and becomes pervasive, E.164-addressed telephone calls need not necessarily traverse the Public Switched Telephone Network (PSTN). Therefore, VoIP service providers have an interest in using ENUM, on a so-called "Infrastructure" basis, to keep VoIP traffic on IP networks on an end-to-end basis, both within and between service provider domains. This requires of means of identifying a VoIP point of interconnection to which calls addressed to a given E.164 number may be delivered and Infrastructure ENUM provides this means. Calls that can originate and terminate on IP networks, and do not have to traverse the PSTN, will require fewer or no points of transcoding, and can also involve additional IP network services that are not possible on the PSTN, among other benefits. Requirements for Infrastructure ENUM are provided in[4]. 3. Zone Apex for Infrastructure ENUM This document proposes that Infrastructure ENUM be implemented by means of a parallel namespace to e164.arpa dedicated to Infrastructure ENUM, in a domain which is to be determined. Use of a parallel namespace allows carriers and end users to control their ENUM registrations for a number independently without forcing one to work through the other. Infrastructure ENUM Tier 2 resource records in the Infrastructure ENUM tree would be controlled by the service provider that is providing services to a given E.164 number, generally referred to in various nations as the "carrier of record" (see [4]). The definition of a carrier of record for a given E.164 number is a national matter or is defined by the entity controlling the numbering space. See also Section 3, Requirements, in [4]. 4. IANA Considerations This document contains no requested IANA actions. IANA has created a registry for Enumservices as originally specified in RFC 2916 and revised in RFC 3761. Enumservices registered with IANA are valid for Infrastructure ENUM as well as end-user ENUM. 5. Security and Privacy Considerations Livingood, et. al. Expires May 16, 2008 [Page 3] Internet-Draft Infrastructure ENUM November 2007 This document proposes a new zone apex for ENUM to meet the requirements of Infrastructure ENUM. The over-the-network protocol of ENUM is unchanged by the addition of an apex, and as such, the Security considerations of RFC3761 [1] still apply. Specific considerations related to the security of an Infrastructure ENUM apex are given in more detail in Section 4, Security Considerations, in [4]. Infrastructure ENUM registrations proposed by this draft should resolve to service provider points of interconnection rather than end user equipment. Service providers need to take appropriate measures to protect their end user customers from unwanted communications as with other types of interconnections. 6. Acknowledgements The authors wish to thank Lawrence Conroy, Patrik Faltstrom, Michael Haberler, Otmar Lendl, Steve Lind, Alexander Mayrhofer, Jim Reid, and Richard Shockey for their helpful discussion of this draft and the concept of Infrastructure ENUM. 7. References 7.1 Normative References [1] Faltstrom, P. and M. Mealling, "The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM)", RFC 3761, April 2004. [2] ITU-T, "The International Public Telecommunication Number Plan", Recommendation E.164, February 2005. [3] Mockapetris, P., "DOMAIN NAMES - CONCEPTS AND FACILITIES", RFC 1034, November 1987. [4] Lind, S., Pfautz, P., "Infrastructure ENUM Requirements", draft- ietf-enum-infrastructure-enum-reqs-04, May 2007. [5] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. 7.2 Informative References None Authors' Addresses Jason Livingood Livingood, et. al. Expires May 16, 2008 [Page 4] Internet-Draft Infrastructure ENUM November 2007 Comcast Cable Communications 1500 Market Street Philadelphia, PA 19102 USA Phone: +1-215-981-7813 Email: jason_livingood@cable.comcast.com Penn Pfautz AT&T 200 S. Laurel Ave Middletown, NJ 07748 USA Phone: +1-732-420-4962 Email: ppfautz@att.com Richard Stastny Oefeg Postbox 147 1103 Vienna Austria Phone: +43-664-420-4100 Email: Richard.stastny@oefeg.at Intellectual Property and Copyright Statements Full Copyright Statement 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. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf- ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is currently provided by the IETF Administrative Support Activity (IASA). Livingood, et. al. Expires May 16, 2008 [Page 6]