ENUM -- Telephone Number Mapping O. Lendl Working Group enum.at Internet-Draft May 16, 2006 Expires: November 17, 2006 The ENUM Branch Location Record draft-lendl-enum-branch-location-record-01 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 November 17, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This documents defines the ENUM Branch Location record which is used to indicate where the ENUM tree for special ENUM application is located. The primary application for the EBL is to enable a temporary solution for the infrastructure ENUM tree. Lendl Expires November 17, 2006 [Page 1] Internet-Draft ENUM Branch Location Record May 2006 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. ENUM Tree Referrals . . . . . . . . . . . . . . . . . . . . . 3 3. The EBL Resource Record . . . . . . . . . . . . . . . . . . . 3 3.1 The EBL RDATA Format . . . . . . . . . . . . . . . . . . . 4 3.2 The EBL Presentation Format . . . . . . . . . . . . . . . 4 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.1 Normative References . . . . . . . . . . . . . . . . . . . 5 8.2 Informative References . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 6 Intellectual Property and Copyright Statements . . . . . . . . 7 Lendl Expires November 17, 2006 [Page 2] Internet-Draft ENUM Branch Location Record May 2006 1. Introduction ENUM as defined in RFC3761 [1] (User-ENUM) is not well suited for the purpose of interconnection by carriers, as can be seen by the use of various private tree arrangements based on ENUM mechanisms. Using the same E.164 number to domain mapping technique for other application under a different apex (instead of e164.arpa) is straightforward on the technical side. Establishing the international agreements necessary to delegate the country-code level subdomains under the new apex is non-trivial and time-consuming. This process is under way [4]. ENUM Branch Location records as defined by this document can be used to quickly introduce new ENUM trees on a per-country opt-in basis by storing the layout of new trees in the User-ENUM tree. While Infrastructure ENUM is the motivation for the introduction of the EBL record, its use it not limited to Infrastructure ENUM. More information and motivation can be found in draft-ietf-enum-infrastructure-enum-reqs [3] and draft-haberler-carrier-enum [5]. 2. ENUM Tree Referrals To allow maximum flexibility, the following parameters will be used in ENUM tree referrals. application: indicating to what kind of application this EBL applies to. In the case of Infrastructure ENUM, this will be "infrastructure". separator: indicating what label should be inserted into the ENUM domain to branch off to the application-specific tree. This can be an empty (zero-length) string. position: indicating at what place this what label should be inserted into the ENUM domain to branch off to the application-specific tree. A value of 0 means to the right of all digits. apex: indicating what domain should replace "e164.arpa" for this application. The "application" acts as the selector and is stored as the label in the DNS. The other three parameters make up the content of the EBL. 3. The EBL Resource Record The EBL will reside within the country-code level in the User-ENUM tree under e164.arpa. Lendl Expires November 17, 2006 [Page 3] Internet-Draft ENUM Branch Location Record May 2006 The RR type code for the EBL RR is /IANA-ACTION/. 3.1 The EBL RDATA Format The RDATA for a EBL RR consists of a position number, separator string and an apex domain. and refer to the definitions of RFC 1035 [2]. 0 1 2 3 4 5 6 7 +--+--+--+--+--+--+--+--+ | POSITION | +--+--+--+--+--+--+--+--+ / SEPARATOR / +--+--+--+--+--+--+--+--+ / APEX / +--+--+--+--+--+--+--+--+ where POSITION is a single byte, SEPARATOR is a and APEX is a . Name-compression is not to be used for the APEX field. 3.2 The EBL Presentation Format The master file format follows the standard rules in RFC 1035. POSITION is represented as decimal integer. SEPARATOR is a quoted string, APEX is a domain name and thus does not require quoting. 4. Examples infrastructure.3.4.e164.arpa IN EBL 2 "i" e164.arpa. infrastructure.1.e164.arpa IN EBL 4 "i" example.com. infrastructure.9.4.e164.arpa IN EBL 0 "" e164i.arpa. This records indicates how the transformation from E.164 number to ENUM domains for the application "infrastructure" should be done for numbers in country code +43, +1, and +49. This leads to the following mappings: +43 15056416 6.1.4.6.5.0.5.i.3.4.e164.arpa +1 5551234567 7.6.5.4.3.2.1.i.5.5.5.1.example.com +49 891234567 7.6.5.4.3.2.1.9.8.e164i.arpa 5. Security Considerations EBLs are used to direct the ENUM resolvers to other places in the DNS for certain applications. As these EBLs are stored in the User-ENUM Lendl Expires November 17, 2006 [Page 4] Internet-Draft ENUM Branch Location Record May 2006 tree, these applications therefore depend on the security of the User-ENUM tree. 6. IANA Considerations This documents allocates the Resource Records Type field for the EBL record. 7. Acknowledgements The author would like to thank Michael Haberler and Richard Stastny for their contributions. 8. References 8.1 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] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. 8.2 Informative References [3] Lind, S. and P. Pfautz, "Infrastrucure ENUM Requirements", draft-ietf-enum-infrastructure-enum-reqs-02 (work in progress), April 2006. [4] Livingood, J., "The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application for Infrastructure ENUM", draft-ietf-enum-infrastructure-00 (work in progress), April 2006. [5] Haberler, M. and R. Stastny, "Combined User and Carrier ENUM in the e164.arpa tree", draft-haberler-carrier-enum-02 (work in progress), March 2006. Lendl Expires November 17, 2006 [Page 5] Internet-Draft ENUM Branch Location Record May 2006 Author's Address Otmar Lendl enum.at GmbH Karlsplatz 1/9 Wien A-1010 Austria Phone: +43 1 5056416 33 Email: otmar.lendl@enum.at URI: http://www.enum.at/ Lendl Expires November 17, 2006 [Page 6] Internet-Draft ENUM Branch Location Record May 2006 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2006). 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Lendl Expires November 17, 2006 [Page 7]